This proxy statement and the accompanying proxy card are being made available to stockholders online at www.proxyvote.com. You may request copies of this proxy statement and any other publicly available information concerning Summit, without charge, from Innisfree M&A Incorporated, Summit’s proxy solicitor, by calling (877) 717-3904, (banks and brokers can call collect at (212) 750-5833). Our SEC filings are also available on our website, free of charge, at http://www.summit-materials.com as soon as reasonably practicable after they are filed with or furnished to the SEC, or from the SEC through the SEC website at www.sec.gov.

In order for Summit stockholders to receive timely delivery of the documents in advance of the Special Meeting to be held on [•], you must request the information by [•] (five business days prior to the date of the Special Meeting).

Throughout this proxy statement, references to “Summit Materials, Inc.” or “Summit” refer to Summit Materials, Inc., a Delaware corporation, and not its consolidated subsidiaries, and references to “we,” “us,” “our” and the “Company” refer collectively to Summit Materials, Inc. and its consolidated subsidiaries.

In addition, throughout this proxy statement, except as otherwise indicated:

This proxy statement includes “forward-looking statements” within the meaning of the federal securities laws, which involve risks and uncertainties. Forward-looking statements include all statements that do not relate solely to historical or current facts, and you can identify forward-looking statements because they contain words such as “believes,” “expects,” “may,” “will,” “outlook,” “should,” “seeks,” “intends,” “trends,” “plans,” “estimates,” “projects” or “anticipates” or similar expressions that concern our strategy, plans, expectations or intentions. All statements made relating to our estimated and projected earnings, margins, costs, expenditures, cash flows, growth rates and financial results are forward-looking statements. Such forward-looking statements include but are not limited to statements about the benefits of the proposed Transaction (as defined below), including future financial and operating results, the combined company’s plans, objectives, expectations and intentions, and other statements that are not historical facts. These forward-looking statements are subject to risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from future results, performance or achievements expressed or implied by such forward-looking statements.

We derive many of our forward-looking statements from our operating budgets and forecasts, which are based upon many detailed assumptions. While we believe that our assumptions are reasonable, it is very difficult to predict the effect of known factors, and, of course, it is impossible to anticipate all factors that could affect our actual results. In light of the significant uncertainties inherent in the forward-looking statements included herein, the inclusion of such information should not be regarded as a representation by us or any other person that the results or conditions described in such statements or our objectives and plans will be realized. Important factors could affect our results and could cause results to differ materially from those expressed in our forward-looking statements, including but not limited to the factors discussed in the section entitled “Risk Factors” in our Annual Report and any factors discussed in the section entitled “Risk Factors” in this proxy statement and in any of our subsequently filed SEC filings; and the following:

All subsequent written and oral forward-looking statements attributable to us, or persons acting on our behalf, are expressly qualified in their entirety by these cautionary statements. Any forward-looking statement that we make herein speaks only as of the date of this proxy statement. We undertake no obligation to publicly update or revise any forward-looking statement as a result of new information, future events or otherwise, except as required by law.

Stockholders will consider and vote upon the following items if each is properly presented at the Special Meeting:

The Board unanimously recommends that stockholders vote “FOR” the approval of the Common Stock Issuance Proposal, “FOR” the approval of the Preferred Stock Issuance Proposal and “FOR” the approval of the Adjournment Proposal.

For certain regulatory reasons, it is important that Cementos Argos’s voting interest is not involuntarily diluted below 25.01% of the Common Stock. As a result, Summit will issue the Preferred Share at the closing in order to provide Cementos Argos with a short window in which Cementos Argos will have the ability to purchase shares of Class A Common Stock in the market, in certain limited circumstances, to prevent Cementos Argos from being involuntarily diluted below 25.01%. The Preferred Share will entitle Cementos Argos to no economic rights whatsoever (and no dividends or other distributions will be declared or paid on the Preferred Share). See “The Transaction — The Transaction Agreement — Certificate of Designation; Preferred Share” for more information.

Pursuant to the Transaction Agreement, and upon the terms and subject to the conditions set forth therein, Summit will acquire all of the issued and outstanding equity interests of Argos USA.

As a result of the Transaction, the total number of issued shares of Class A Common Stock outstanding will increase by approximately 54,720,000 shares, which as of [•] was approximately [•].

As of immediately following the closing, the Board will be comprised of eleven or fewer directors, including three individuals designated by Cementos Argos as its nominees, who will be appointed to the Board at the closing. In addition, one current director of the Board will step down from his or her position as a board member. Following the closing, the Company will continue to be led by Anne P. Noonan, as Summit’s President and CEO.

If we increase the size of the Board following closing, Cementos Argos will be permitted to appoint additional nominees to the Board in an amount necessary to retain greater than 25.01% representation on the Board, for as long as Cementos Argos holds more than 25% of the outstanding Class A Common Stock of Summit.

In connection with the entry into the Transaction Agreement, Summit Materials, LLC entered into a commitment letter (as amended and restated, the “Debt Commitment Letter”) with Morgan Stanley Senior Funding, Inc., Goldman Sachs Bank USA, Royal Bank of Canada, Citigroup Global Markets Inc., Barclays Bank PLC, Capital One, National Association, PNC Bank, National Association and PNC Capital Markets LLC (the “Commitment Parties”), pursuant to which the Commitment Parties have committed, subject to customary terms and conditions, to provide Summit Materials, LLC with debt financing for the Transaction consisting of an up to $1,300 million senior 364-day term loan bridge facility (the “Debt Commitment Financing”). The amount of the Debt Commitment Financing available at closing is subject to reduction in accordance with the terms of the Debt Commitment Letter, including, but not limited to, reduction from certain debt issuances by Summit. The aggregate net proceeds contemplated by the Debt Commitment Financing, including the proceeds of any debt issuances contemplated thereby, will be used to pay the cash Consideration for the Transaction and pay related transaction costs. Certain of the Commitment Parties or their respective affiliates have provided, or may in the future provide, certain commercial banking, financing advisory, investment banking and other services in the course of business for the Company, its subsidiaries and certain of its affiliates, for which they have received customary fees and commissions.

There are a number of closing conditions set forth in the Transaction Agreement, including the expiration of the applicable waiting period under the HSR Act and the approval by Summit’s stockholders of the Common Stock Issuance Proposal and the Preferred Stock Issuance Proposal. For a summary of the conditions that must be satisfied or waived prior to completion of the Transaction, please see the section entitled “The Transaction — The Transaction Agreement — Conditions to Closing of the Transaction.”

The Special Meeting will be held at [8:00] [a.m.] Mountain Time on [day of week], [date] at 1801 California Street, [Suite 3500], Denver, CO 80202.

To attend the Special Meeting, you will need proof of ownership of Common Stock to enter the meeting. If your shares are in the name of your broker or bank or you received your materials electronically, you will need to bring evidence of your stock ownership, such as your most recent brokerage statement and a “legal proxy” from the bank, brokerage firm or other nominee that hold your shares. Everyone will be required to present a valid picture ID.

No cameras, recording equipment, laptops, tablets, cellular telephones, smartphones, or other similar equipment, electronic devices, large bags, briefcases or packages will be permitted, and security measures will be in effect to provide for the safety of attendees. As always, we encourage you to vote your shares prior to the Special Meeting.

You may vote if you held Class A Common Stock or Class B Common Stock at the close of business on [record date].

Each share of Class A Common Stock is entitled to one vote for each item to be voted on at the Special Meeting. All of the shares of our outstanding Class B Common Stock are currently held by our pre-IPO investors, including certain members of management that directly hold LP Units. A holder of Class B Common Stock is entitled, without regard to the number of shares of Class B Common Stock held by such holder, to a number of votes that is equal to the aggregate number of LP Units held by such holder. As of the record date, the total number of LP Units to which the voting power of the Class B Common Stock relates was [•].

If your shares are registered directly in your name with Summit’s transfer agent, Broadridge, you are considered the “stockholder of record” of those shares. The notice relating to the Special Meeting (the “Notice”), this proxy statement and accompanying materials have been sent to you directly by Broadridge.

If your shares are held in a stock brokerage account or by a bank or other holder of record, you are considered the “beneficial owner” of shares held in “street name.” The Notice, this proxy statement and accompanying materials have been forwarded to you by your broker, bank or other holder of record that is considered the “stockholder of record” of those shares. As the beneficial owner, you have the right to direct your broker, bank or other holder of record in voting your shares by using the voting instruction form (“VIF”) included in the mailing or by following the instructions from the holder of record. Please instruct your broker, bank or other holder of record how to vote your shares using the VIF you received from them. Please return your completed VIF to your broker, bank or other holder of record and contact the person responsible for your account so that your vote can be counted.

We encourage you to vote your shares in advance of the Special Meeting, even if you plan on attending the Special Meeting. If you have already voted prior to the Special Meeting, you may nevertheless change or revoke your vote at the Special Meeting.

Vote your shares as follows:

If you vote by submitting your proxy card, your shares will be voted as indicated on your properly completed, unrevoked proxy card. If you return your proxy card but do not indicate how your shares should be voted on a proposal, the shares represented by your properly completed, unrevoked proxy card will be voted as recommended by the Board with respect to such proposal. If you do not return a properly completed proxy card and do not vote by physically attending the Special Meeting, by telephone or on the Internet, your shares will not be voted.

In the case of internet or telephone voting, you should have your proxy card in hand and retain the card until you have completed the voting process. If you vote by internet or telephone, you do not need to return the proxy card by mail. Even if you plan to attend the meeting physically, we encourage you to vote by proxy as soon as possible.

If your shares are held by a broker, bank or other holder of record in “street name”, you should receive a VIF along with a copy of this proxy statement.

Your broker, bank or other holder of record (or designee thereof) will vote your shares in accordance with the instructions on your returned VIF. You may instruct the holder of record to vote your shares by completing the VIF as outlined in the instructions on the form and signing, dating and returning the VIF in the prepaid

envelope provided. You may also submit your vote by telephone or on the Internet if those options are made available to you by your broker, bank or other holder of record. Although most banks, brokers and other nominees offer these voting alternatives, availability and specific procedures vary. Please instruct your broker, bank or other holder of record how to vote your shares so that your vote can be counted. Please review your VIF for the date by which your instructions must be received in order for your shares to be voted.

You may also vote at the Meeting Location if you bring evidence of your stock ownership, such as your most recent brokerage statement and a “legal proxy” from the bank, brokerage firm or other nominee that hold your shares. Everyone will be required to present a valid picture ID to enter the Special Meeting.

See “Is my vote important and how are the votes counted?” below for the right of brokers, banks and other holders of record to vote on routine matters for which they have not received voting instructions.

If you are a stockholder of record, you may revoke your proxy before polls are closed at the Special Meeting by:

Physical attendance at the Special Meeting alone is not sufficient to revoke a prior properly submitted proxy.

If you are a beneficial owner of shares, you may submit new voting instructions by contacting your broker, bank or other holder of record.

This means that you have multiple accounts holding Summit shares. These may include accounts with Summit’s transfer agent, accounts with a broker, bank or other holder of record. In order to vote all of the shares held by you in multiple accounts, you will need to vote separately the shares held in each account. Please follow the voting instructions provided on each proxy card, direction card and/or VIF to ensure that all of your shares are voted.

You are encouraged to have all accounts registered in the same name and address whenever possible. You can do this by contacting Summit’s transfer agent, Broadridge, at 51 Mercedes Way, Edgewood, NY 11717, at its toll-free number 877-830-4936 or on its website at https://shareholder.broadridge.com. If you receive more than one VIF, please contact the broker, bank or other holder of record holding your shares to determine whether you can consolidate your accounts.

SEC rules permit us to deliver a single copy of our proxy statement to any household at which two or more stockholders reside if we believe the stockholders are members of the same family. This practice benefits both you and Summit, as it eliminates duplicate mailings and reduces our printing and mailing costs. Each stockholder will continue to receive a separate proxy card or voting instruction card.

Your household may have received a single copy of this proxy statement. If you prefer to receive your own copy, please request a duplicate set by phone at 1-866-540-7095, online at www.proxyvote.com, or by writing to Summit Materials, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717.

If you hold your stock in street name, you may receive some duplicate mailings. Certain brokers will eliminate duplicate account mailings on request. You may need to contact your broker directly if you want to discontinue duplicate mailings to your household. You can also register to receive all future stockholder communications electronically, instead of in print. This means that links to the proxy statement, and other correspondence will be delivered to you via e-mail. Holders in street name can register for electronic delivery directly with their bank, brokerage firm, or other nominee. Electronic delivery of stockholder communications helps save the Company money by reducing printing and postage costs.

If you are a beneficial owner whose shares are held of record by a broker, bank or other holder of record, you have the right to direct your broker, bank or other holder of record in voting your shares. If the beneficial owner does not provide voting instructions, the broker, bank or other holder of record cannot vote the shares with respect to “non-routine” matters, but can vote the shares with respect to “routine” matters. “Broker non-votes” occur when a beneficial owner of shares held in street name fails to provide instructions to the broker, bank or other holder of record as to how to vote on matters deemed “non-routine.”

We believe that each of the Common Stock Issuance Proposal, the Preferred Stock Issuance Proposal and the Adjournment Proposal are “non-routine” matters and, as a result, your broker, bank or other holder of record cannot vote your shares without your instruction on any of the proposals presented at the Special Meeting. If you do not provide instructions with your proxy, your broker, bank or other holder of record may deliver a proxy card expressly indicating that it is NOT voting your shares; this indication that a broker, bank or other holder of record is not voting your shares is referred to as a “broker non-vote.” Broker non-votes will not be counted for the purposes of determining the existence of a quorum or for purposes of determining the number of votes cast at the Special Meeting. Your bank, broker or other holder of record can vote your shares only if you provide instructions on how to vote. You should instruct your broker, bank or other holder of record to vote your shares in accordance with directions you provide.

At the close of business on the record date for the Special Meeting, there were [•] shares of Class A Common Stock outstanding and [•] shares of Class B Common Stock outstanding. The following are the voting requirements to approve the proposals presented in this proxy statement and the discretionary authority of brokers, banks or other holders of record with respect to each proposal:

For purposes of the approval of the proposals above, broker non-votes, if any, and the failure to vote are not votes that are present in person or by proxy and, accordingly, will have no effect on the outcome of such proposals. Broker non-votes will not be counted for the purpose of determining the existence of a quorum at the Special Meeting.

For purposes of the approval of the proposals above, abstentions will be counted in connection with the determination of whether a valid quorum is established, but an abstention will have the same effect as a vote “AGAINST” the Common Stock Issuance Proposal,“AGAINST” the Preferred Stock Issuance Proposal and “AGAINST” the Adjournment Proposal.

A quorum of Summit’s stockholders is necessary to hold a valid meeting. A quorum will be present at the Special Meeting if the holders of a majority of the voting power of Common Stock entitled to vote as of the close of business on the record date are present in person (which includes virtual attendance as a stockholder at the Special Meeting) or represented by proxy at the Special Meeting. Abstentions will be included in determining the presence of a quorum at the Special Meeting. Broker non-votes will not be included in determining the presence of a quorum at the Special Meeting.

Your vote is very important. Each share of Class A Common Stock that you own at the close of business on [record date], the record date for the Special Meeting, represents one vote. Each share of Class B Common Stock that you own at the close of business on [record date], the record date for the Special Meeting, represents, without regard to the number of shares of Class B Common Stock you hold, a number of votes that is equal to the aggregate number of LP Units you hold. If you do not vote your shares, you will not have a say on the important issues to be voted on at the meeting.

As of the date of this proxy statement, we do not know of any other matters that may be presented for action at the Special Meeting. However, should other matters properly come before the Special Meeting, the persons named as proxies will vote in a manner as they may, in their discretion, determine.

If the Special Meeting is postponed or adjourned, your proxy will still be valid and may be voted at the postponed or adjourned meeting. You will still be able to change or revoke your proxy until it is voted. See “May I change my vote?” above.

We do. We are soliciting proxies primarily by use of mail. However, we may also solicit proxies in person, by telephone, by facsimile, by courier or by electronic means. To the extent that our directors, officers or other employees participate in this solicitation, they will not receive any compensation for their participation, other than their normal compensation. Innisfree assists us with the solicitation for a fee of $40,000, plus reasonable out-of-pocket expenses. We also reimburse brokerage firms and other custodians, nominees and fiduciaries for their reasonable out-of-pocket expenses for sending proxy materials to stockholders and obtaining their proxies.

You may contact Summit’s Executive Vice President, Chief Legal Officer & Secretary by sending correspondence to: Summit Materials, Inc., 1801 California Street, Suite 3500, Denver, Colorado 80202, by [date].

If you have questions about the proposals or if you need additional copies of this proxy statement or the enclosed proxy card you should contact:

You may also contact Summit’s proxy solicitor at:

To obtain timely delivery, Summit stockholders must request the materials no later than five business days prior to the Special Meeting.

You may also obtain additional information about us from documents filed with the SEC by following the instructions in the section entitled “Where You Can Find Additional Information; Incorporation of Certain Documents by Reference.”

The SEC has an informational website that provides stockholders with general information about how to cast their vote and why voting should be an important consideration for stockholders. You may access that information at www.sec.gov/spotlight/proxymatters.shtml or at www.investor.gov.

You should carefully review and consider the following risk factors and the other information contained in this proxy statement, including the financial statements and notes to the financial statements included herein, in evaluating the Transaction and the proposals to be voted on at the Special Meeting. The occurrence of one or more of the events or circumstances described in these risk factors, alone or in combination with other events or circumstances, may have an adverse effect on the business, cash flows, financial condition and results of operations of the Company. You should also carefully consider the following risk factors in addition to the other information included in this proxy statement, including matters addressed in the section entitled “Cautionary Statement Regarding Forward-Looking Statements.” We, Cementos Argos and/or Argos USA may face additional risks and uncertainties that are not presently known to us, Cementos Argos and/or Argos USA, or that we, Cementos Argos and/or Argos USA currently deem immaterial, which may also impair our, Cementos Argos’s, and/or Argos USA’s business or financial condition. The following discussion should be read in conjunction with the financial statements and notes to the financial statements included herein.

Completion of the Transaction is subject to a number of conditions, including, among other things, obtaining the approval of Summit’s stockholders of the issuance of the shares of Class A Common Stock that constitute the Class A Consideration, the issuance of one share of preferred stock that constitutes the Preferred Share and the expiration of the applicable waiting period under the HSR Act. Such conditions, some of which are beyond our control, may not be satisfied or waived in a timely manner or at all and therefore make the completion and timing of the completion of the Transaction uncertain. In addition, the Transaction Agreement contains certain termination rights for both us and Cementos Argos, which, if exercised, will also result in the Transaction not being consummated. Furthermore, the governmental authorities from which the regulatory approvals are required may impose conditions on the completion of the Transaction or require changes to the terms thereof. Such conditions or changes and the process of obtaining regulatory approvals could have the effect of delaying or impeding consummation of the Transaction or of imposing additional costs or limitations on us, Cementos Argos or Argos USA following completion of the Transaction, any of which might have an adverse effect on us following completion of the Transaction.

If the Transaction is not completed, our ongoing business may be adversely affected and, without realizing any of the benefits of having completed the Transaction, we will be subject to a number of risks, including the following:

In addition to the above risks, if the Transaction Agreement is terminated and the Board seeks another acquisition, Summit’s stockholders cannot be certain that we will be able to find a party willing to enter into a transaction as attractive to us as the Transaction. Also, if the Transaction Agreement is terminated under certain specified circumstances, Summit would be required to pay Cementos Argos a Termination Fee.

Upon completion of the Transaction, Cementos Argos will become the holder of shares of Class A Common Stock and one Preferred Share convertible or exercisable into a certain number of Class A Common Stock. For additional information, please see “The Transaction — The Transaction Agreement — Certificate of Designation; Preferred Share.” The market price of shares of Common Stock may fluctuate significantly following completion of the Transaction and holders of Common Stock could lose some or all of the value of their investment in the Common Stock. In addition, the stock market has experienced significant price and volume fluctuations in recent times which, if they continue to occur, could have a material adverse effect on the market for, or liquidity of, the Common Stock, regardless of Summit's actual operating performance.

In connection with the pendency of the Transaction, it is possible that certain persons with whom we or any of the ANAC Companies have a business relationship may delay or defer certain business decisions or decide to seek to terminate, change or renegotiate their relationships with us or such ANAC Company, as the case may be, as a result of the Transaction, which could negatively affect our or Argos USA’s revenues, earnings and cash flows as well as the market price of Summit’s Class A Common Stock, regardless of whether the Transaction is completed. Also, our and Argos USA’s ability to attract, retain and motivate employees may be impaired until the Transaction is completed, and our ability to do so may be impaired for a period of time thereafter, as current and prospective employees may experience uncertainty about their roles within the Company following the Transaction.

Under the terms of the Transaction Agreement, we are subject to certain restrictions on the conduct of our business prior to the consummation of the Transaction, which may adversely affect our ability to execute certain of our business strategies. Among other restrictions, Summit is restricted, in certain cases, from amending its governing documents in certain ways, paying certain dividends or granting certain equity awards to its employees. Such limitations could negatively affect our businesses and operations prior to the completion of the Transaction.

We have incurred and are expected to continue to incur a number of non-recurring costs associated with the Transaction, combining the operations of Argos USA with ours and achieving desired synergies. These costs have been, and will continue to be, substantial and, in many cases, will be borne by us whether or not the Transaction is completed. A substantial majority of non-recurring expenses will consist of transaction costs and include, among others, fees paid to financial, legal, accounting and other advisors and employee retention, severance and benefit costs. We will also incur costs related to formulating and implementing integration plans. Although we expect that the elimination of duplicative costs, as well as the realization of synergies and efficiencies related to the integration of Argos USA, should allow us to offset these transaction costs over time, this net benefit may not be achieved in the near-term or at all.

Securities class action lawsuits and derivative lawsuits are often brought against public companies that have entered into acquisition, merger or other business combination or transaction agreements. Even if such a lawsuit is without merit, defending against these claims can result in substantial costs and divert management time and other resources. An adverse judgment could result in monetary damages, which could have a negative impact on our liquidity and financial condition.

Lawsuits that may be brought against us, Argos USA or our or its directors could also seek, among other things, injunctive relief or other equitable relief, including a request to enjoin us from consummating the Transaction. One of the conditions to the closing of the Transaction is that there is no law, judgement, decree, writ, injunction, stipulation, ruling, award, decision, subpoena, determination, verdict or order has been entered, issued, made or rendered by any governmental authority or legally binding arbitrator of competent jurisdiction that would prohibit, enjoin, restrain or make illegal the consummation of the Transaction or impose certain burdensome conditions. Consequently, if a plaintiff is successful in obtaining an order, award or judgment prohibiting completion of the Transaction, that order, award or judgment may delay or prevent the Transaction from being completed within the expected time frame or at all, which may adversely affect our business, financial position and results of operations.

The Transaction Agreement contains provisions that may discourage a third party from submitting an acquisition proposal to Summit or Argos USA that might result in greater value to Summit's, Cementos Argos’s or Grupo Argos's respective stockholders than the Transaction, or may result in a potential acquirer of Summit, or a potential competing acquirer of Argos USA, proposing to pay a lower per share price to acquire Summit or

Argos USA, respectively, than it might otherwise have proposed to pay. These provisions include a general prohibition on Summit and Cementos Argos, Argos USA and the Argos Parties from soliciting or, subject to certain exceptions relating to the exercise of fiduciary duties by the Board and entering into discussions with any third party regarding any acquisition proposal or offer for a competing transaction.

The unaudited pro forma condensed combined financial information in this proxy statement is presented for illustrative purposes only and is not necessarily indicative of what our actual financial position or results of operations would have been had the Transaction been completed on the dates indicated. Further, our actual results and financial position after the Transaction may differ materially and adversely from the pro forma information that is included in this proxy statement.

The unaudited pro forma condensed combined financial information has been prepared based upon the assumption that we will be identified as the acquirer under GAAP and reflects adjustments based upon preliminary estimates of the fair value of assets to be acquired and liabilities to be assumed.

On September 5, 2023, Morgan Stanley rendered its oral opinion, which was subsequently confirmed in writing, to the Board to the effect that, as of such date and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Morgan Stanley as set forth in its written opinion, the Consideration to be paid by Summit pursuant to the Transaction Agreement was fair from a financial point of view to Summit. Changes in the operations and prospects of Argos USA or Summit, general market and economic conditions and other factors that may be beyond our control, and on which the opinion of Morgan Stanley was based, may alter our or Argos USA’s value or the price at which shares of our common stock are traded by the time the Transaction is completed. We have not obtained, and we do not expect to request, an updated opinion from our financial advisor. Morgan Stanley’s opinion does not speak to the time when the Transaction will be completed or to any date other than the date of such opinion. As a result, the opinion does not and will not address the fairness, from a financial point of view, of the Consideration to be paid by us in the Transaction pursuant to the Transaction Agreement at the time the Transaction is completed or at any time other than the date when opinion was rendered. For a more complete description of the opinion that our Board received from our financial advisor and a summary of the material financial analyses Morgan Stanley provided to our Board in connection with rendering such opinion, please refer to “The Transaction — Certain Unaudited Financial Projections — Opinion of Financial Advisor to Summit” beginning on page 55 of this proxy statement and the full text of such written opinion included as Annex K to this proxy statement.

The Transaction involves numerous operational, strategic, financial, accounting, legal, tax and other risks, including potential liabilities associated with the acquired business. Difficulties in integrating the business of Argos USA and the Company's ability to manage the post-acquisition company may result in the post-acquisition company performing differently than expected, in operational challenges or in the delay or failure to realize anticipated expense-related efficiencies, and could have an adverse effect on the Company's financial condition, results of operations or cash flows. Potential difficulties that may be encountered in the integration process include, among other factors:

Additionally, the success of the Transaction will depend, in part, on the Company's ability to realize the anticipated benefits from combining Argos USA’s and the Company's businesses, including operational and other synergies that the Company believes the post-transaction company will achieve. The anticipated benefits of the Transaction may not be realized fully or at all, may take longer to realize than expected or could have other adverse effects that the Company does not currently foresee. Some of the assumptions that the Company has made, such as the achievement of operating synergies, may not be realized.

Immediately following the consummation of the Transaction, Cementos Argos will own, in the aggregate, approximately 31% of the outstanding Common Stock. As a result, Cementos Argos will have significant influence over us. Going forward, Cementos Argos’s degree of influence will depend on, among other things, its level of ownership of our common stock and its ability to exercise certain rights under the terms of the Stockholders Agreement that we will enter with Cementos Argos in connection with the Transaction and Transaction Agreement.

Under the Stockholders Agreement, for so long as Cementos Argos continues to beneficially own at greater than 25.0% of the then-outstanding shares of Class A Common Stock, neither Summit nor any of its subsidiaries may take any of the following actions without the prior written consent of Cementos Argos, such approval not to be unreasonably withheld, conditioned or delayed: (i) voluntarily incur “Indebtedness” (as defined in the Credit Agreement) if immediately following such incurrence, either Summit’s (1) Consolidated First Lien Net Leverage Ratio (as defined in the Credit Agreement), or any substantially equivalent term in the Credit Agreement, would exceed 6.00:1.00 or (2) Consolidated Total Net Leverage Ratio (as defined in the Credit Agreement), or any substantially equivalent term in the Credit Agreement, would exceed 8.00:1.00, (ii) enter into any material agreements or arrangements with affiliates of Summit or its subsidiaries providing for payments to such affiliates in excess of $20,000,000, subject to certain exceptions, (iii) fundamentally change the business of Summit and its subsidiaries, taken as a whole, in a manner that would constitute a significant departure from the construction materials industry or result in Summit and its subsidiaries, taken as a whole, ceasing to operate in the construction materials industry, (iv) voluntarily liquidate, dissolve or wind-up the business and affairs of the Company; or (v) authorize, agree or commit to do any of the foregoing.

Accordingly, Cementos Argos’s influence over us could have a negative impact on our business and business prospects and negatively impact the trading price of our common stock.

Following completion of the Transaction, the size of the Company’s business will increase significantly beyond its current size. The Company’s future success will depend, in part, on the Company’s ability to manage this expanded business, which poses numerous risks and uncertainties, including with respect to the need to integrate the operations and business of Argos USA into the Company’s existing business in an efficient and timely manner, to combine systems and management controls and to integrate relationships with customers, vendors and business partners.

Based on the number of outstanding shares of Class A Common Stock as of [record date], 2023, immediately after the Transaction is completed, it is expected that, on a fully-diluted basis, Summit’s current stockholders will collectively own approximately 69% and Cementos Argos will own approximately 31% of the outstanding shares of Class A Common Stock. As a result of the Transaction, Summit’s current stockholders will own a smaller percentage of Summit than they currently own, and as a result will have less influence over Summit’s management and policies.

Shares of Class A Common Stock that are issued to the Cementos Argos in connection with the Transaction will become freely tradable, following the Lock-Up Termination Date, once registered pursuant to the Registration Rights Agreement or sold in compliance with Rule 144 promulgated under the Securities Act (“Rule 144”). Pursuant to the Registration Rights Agreement, all of the shares of Class A Common Stock issued as Stock Consideration to any Investor Participant who is a party to the Registration Rights Agreement may be registered for resale. Once registered, the Class A Common Stock held by such Investor Participant will not be subject to any restrictions or require further registration under the Securities Act.

Cementos Argos may wish to dispose of some or all of their interests in Summit, and as a result may seek to sell their shares of Class A Common Stock. These sales (or the perception that these sales may occur), coupled with the increase in the number of outstanding shares of Class A Common Stock, may affect the market for, and the market price of, the Class A Common Stock in an adverse manner.

If the Transaction is completed and Summit’s stockholders, including the Investor Participants, sell substantial amounts of Class A Common Stock in the public market following the closing of the Transaction, the market price of the Class A Common Stock may decrease. These sales might also make it more difficult for Summit to raise capital by selling equity or equity-related securities at a time and price that it otherwise would deem appropriate.

You should read and consider risk factors specific to the Company’s businesses that will continue to affect the Company after the completion of the Transaction. These risks are described in the Annual Report, which is incorporated by reference herein.

The businesses of the Argos USA and the Company are subject to substantially similar risks and uncertainties. Argos USA’s business is, and will continue to be, subject to the risks described above. In addition, Argos USA’s business is, and will continue to be, subject to the business risks that the Company is subject to and that are described in the Annual Report, which is incorporated by reference herein.

The following is a description of the material aspects of the Transaction. While we believe that the following description covers the material aspects of the Transaction, the description may not contain all of the information that is important to you. We encourage you to carefully read this entire document, including the Transaction Agreement attached to this proxy statement as Annex A, for a more complete understanding of the Transaction. Please see the subsection entitled “— The Transaction Agreement” below for additional information and a summary of certain terms of the Transaction Agreement. You are urged to carefully read the Transaction Agreement in its entirety before voting on this proposal.

The terms of the Transaction Agreement, the Stockholder Agreement, the Registration Rights Agreement, the Restrictive Covenants Agreement, the Transition Services Agreement, the Support Services Agreement, the Cement Supply Agreement, the Intellectual Property License Agreement, the Logistics Agreement (Cartagena), the Master Purchase Agreement and the Logistics Agreement (International) are complex and only briefly summarized below. For further information, please see the full text of the Transaction Agreement, which is attached as Annex A hereto, the form of Stockholder Agreement, which is attached as Annex B hereto, the Registration Rights Agreement term sheet, which is attached as Exhibit B to the Stockholder Agreement attached as Annex B hereto, the Restrictive Covenants Agreement, which is attached as Annex C hereto, the Transition Services Agreement, which is attached as Annex D hereto, the Support Services Agreement, which is attached as Annex E hereto, the Cement Supply Agreement, which is attached as Annex F hereto, Intellectual Property License Agreement, which is attached as Annex G hereto, the Logistics Agreement (Cartagena) , which is attached as Annex H hereto, the Master Purchase Agreement, which is attached as Annex I hereto, and the Logistics Agreement (International) , which is attached as Annex J hereto. The discussion herein is qualified in its entirety by reference to such documents.

This subsection of the proxy statement describes the material provisions of the Transaction Agreement, but does not purport to describe all of the terms of the Transaction Agreement. The following summary is qualified in its entirety by reference to the complete text of the Transaction Agreement, which is attached as Annex A hereto. You are urged to read the Transaction Agreement in its entirety because it is the primary legal document that governs the Transaction.

The Transaction Agreement contains representations, warranties and covenants that the respective parties made to each other as of the date of the Transaction Agreement, as of the closing date, or as of other specific dates. The assertions embodied in those representations, warranties and covenants were made for purposes of the contract among the respective parties and are subject to important qualifications and limitations agreed to by the parties in connection with negotiating the Transaction Agreement. The representations, warranties and covenants in the Transaction Agreement are also modified in important part by the underlying disclosure schedules, which are not filed publicly and which are subject to a contractual standard of materiality different from that generally applicable to stockholders and were used for the purpose of allocating risk among the parties rather than establishing matters as facts.

On September 7, 2023, Summit entered into the Transaction Agreement with Argos USA, Cementos Argos, and the Argos Parties, pursuant to which, upon the terms and subject to the conditions set forth therein, Summit will acquire all of the outstanding equity interests of Argos USA from the Argos Parties. After giving effect to the Transaction, it is anticipated that Summit’s current stockholders will own approximately 69% of Summit and Cementos Argos will indirectly own, in the aggregate, approximately 31% of Summit.

Pursuant to the terms and conditions of the Transaction Agreement, the aggregate consideration to be paid to the Argos Parties in the Transaction will consist of (i) $1.2 billion of cash (subject to customary adjustments), (ii) 54,720,000 shares of Class A Common Stock and (iii) one Preferred Share of Summit. Adjustments to the Closing Consideration will be estimated on the closing date, with any upward or downward adjustments to the Closing Consideration to be made against the Cash Consideration. Unless there is a dispute with respect to Closing Consideration adjustments, the Closing Consideration adjustments will then be trued-up promptly following the closing to account for the actual amounts of such adjustments as of the closing. To the extent the final Closing Consideration after accounting for all adjustments is less than or greater than the estimated Closing

Consideration determined on the closing, such further adjustments will be made in cash. The Transaction Agreement contains customary representations and warranties, covenants and agreements.

In connection with the Transaction Agreement, Summit and Cementos Argos and/or certain of their affiliates will enter into certain related agreements, including the Stockholder Agreement, the Registration Rights Agreement, the Restrictive Covenant Agreements, the Transition Services Agreement, the Support Services Agreement, the Cement Supply Agreement, Intellectual Property License Agreement, Logistics Service Agreement (Cartagena), Master Purchase Agreement, and Logistics Support Agreement (International) and other agreements, documents, instruments and certificates contemplated by the Transaction Agreement to be executed in connection with the transactions contemplated thereby.

Under the Transaction Agreement, certain representations and warranties of Argos USA are qualified in whole or in part by a “Material Adverse Effect” standard for purposes of determining whether a breach of such representations and warranties has occurred. Pursuant to the Transaction Agreement, an “Argos USA Material Adverse Effect” means any event, change, circumstance, effect, occurrence, condition, state of facts or development (an “Effect”) that, individually or in the aggregate, has had or would reasonably be expected to have a material adverse effect on the condition (financial or otherwise), business, assets, financial condition or results of operations of the ANAC Companies, taken as a whole, excluding any event, change, circumstance, effect, occurrence, condition, state of facts or development to the extent arising or resulting from (A) Effects generally in financial or securities markets or in the general economic, political, regulatory or business conditions in the jurisdictions where the ANAC Companies have operations, (B) Effects generally affecting the industries in which the ANAC Companies operate, (C) Effects in applicable law or in GAAP (or interpretations or enforcement thereof), (D) Effects resulting from acts of war (whether or not declared), terrorism, civil disobedience, sabotage, military actions or the escalation of any of the foregoing, whether perpetrated or encouraged by a state or non-state actor or actors (including cyberattacks), any weather or natural disaster, or any outbreak or worsening of illness or other public health event (including COVID-19), any restrictions that relate to or arise out of any such illness or public health event (including any COVID-19 measures), (E) the public announcement, pendency or consummation of the Transaction Agreement or any of the other Transaction Documents or the Transaction, including the impact thereof on the relationships, contractual or otherwise, of any ANAC Company or the business, operations and activities of the ANAC Companies as conducted or operated during the 12-month period prior to the date of the Transaction Agreement (the “ANAC Business”) with customers, governmental authorities, employees, labor organizations, suppliers, distributors, financing sources, partners or others with similar relationships (provided that clause (E) will not apply to a breach of any representation, warranty or covenant to the extent the purpose of such representation, warranty or covenant is to address the consequences resulting from the announcement, pendency or consummation of the Transaction Agreement or any of the other Transaction Documents or the Transaction, including for the purposes of Article 9 of the Transaction Agreement (the parties’ conditions to closing of the Transaction)), (F) any actions not permitted to be taken by Cementos Argos, any Argos Party or any ANAC Company due to Section 6.01(b) of the Transaction Agreement (Argos USA’s interim operating covenants), for which Summit declines to provide its consent after Cementos Argos’s reasonable written request therefor (provided that clause (F) will not apply to a breach of any representation, warranty or covenant to the extent the purpose of such representation, warranty or covenant is to address the consequences resulting from the announcement or pendency of the Transaction Agreement or any of the other Transaction Documents or the consummation of the Transaction, including for the purposes of Article 9 of the Transaction Agreement (the parties’ conditions to closing of the Transaction)) or (G) any failure of any of the ANAC Companies to meet, with respect to any period or periods, any internal projections, forecasts, estimates of earnings or revenues or business plans (but not the underlying facts, basis or circumstances giving rise to such failure to meet projections, forecasts, estimates of earnings or revenues or business plans, which may be taken into account in determining whether there has been or would reasonably be expected to be an Argos USA Material Adverse Effect); provided, however, that if any Effect described in any of clauses (A) through (D) has a disproportionate and adverse effect on the ANAC Companies, taken as a whole, relative to other participants in the industry in which the ANAC Companies operate, the impact thereof will be taken into account in determining whether there has been, or would reasonably be expected to be, an Argos USA Material Adverse Effect but solely to the extent of such disproportionate and adverse effect, and then only to the extent otherwise permitted by this definition.

Under the Transaction Agreement, certain representations and warranties of Summit are qualified in whole or in part by a “Material Adverse Effect” standard for purposes of determining whether a breach of such representations and warranties has occurred. Pursuant to the Transaction Agreement, a “Summit Material Adverse Effect” means any Effect that, individually or in the aggregate, has had or would reasonably be expected to have a material adverse effect on the condition (financial or otherwise), business, assets, financial condition or results of operations of Summit or any of its subsidiaries, taken as a whole, excluding any event, change, circumstance, effect, occurrence, condition, state of facts or development to the extent arising or resulting from (A) Effects generally in financial or securities markets or in the general economic, political, regulatory or business conditions in the jurisdictions where Summit or any of its subsidiaries have operations, (B) Effects generally affecting the industries in which Summit or any of its subsidiaries operate, (C) Effects in applicable law or in GAAP (or interpretations or enforcement thereof), (D) Effects resulting from acts of war (whether or not declared), terrorism, civil disobedience, sabotage, military actions or the escalation of any of the foregoing, whether perpetrated or encouraged by a state or non-state actor or actors (including cyberattacks), any weather or natural disaster, or any outbreak or worsening of illness or other public health event (including COVID-19), any restrictions that relate to or arise out of any such illness or public health event (including any COVID-19 measures), (E) the public announcement, pendency or consummation of the Transaction Agreement or any of the other Transaction Documents or the Transaction, including the impact thereof on the relationships, contractual or otherwise, Summit or any of its subsidiaries with customers, governmental authorities, employees, labor organizations, suppliers, distributors, financing sources, partners or others with similar relationships (provided that clause (E) will not apply to a breach of any representation, warranty or covenant to the extent the purpose of such representation, warranty or covenant is to address the consequences resulting from the announcement, pendency or consummation of the Transaction Agreement or any of the other Transaction Documents or the Transaction, including for purposes of Article 9 of the Transaction Agreement (the parties’ conditions to closing of the Transaction), (F) any actions not permitted to be taken by Summit due to Section 6.02(b) of the Transaction Agreement (Summit’s interim operating covenants), for which Cementos Argos declines to provide its consent after Summit’s reasonable written request therefor (provided that clause (F) will not apply to a breach of any representation, warranty or covenant to the extent the purpose of such representation, warranty or covenant is to address the consequences resulting from the announcement or pendency of the Transaction Agreement or any of the other Transaction Documents or the consummation of the Transaction, including for purposes of Article 9 of the Transaction Agreement (the parties’ conditions to closing of the Transaction)), or (G) any failure of any of Summit to meet, with respect to any period or periods, any internal or public projections, forecasts, estimates of earnings or revenues or business plans (but not the underlying facts, basis or circumstances giving rise to such failure to meet projections, forecasts, estimates of earnings or revenues or business plans, which may be taken into account in determining whether there has been or would reasonably be expected to be a Summit Material Adverse Effect); provided, however, that if any Effect described in any of clauses (A) through (D) has a disproportionate and adverse effect on Summit and its subsidiaries, taken as a whole, relative to other participants in the industry in which Summit or any of its subsidiaries operate, the impact thereof will be taken into account in determining whether there has been, or would reasonably be expected to be, a Summit Material Adverse Effect but solely to the extent of such disproportionate and adverse effect, and then only to the extent otherwise permitted by this definition.

The closing of the Transaction is scheduled to take place in New York, NY at the offices of Davis Polk, or remotely by the electronic exchange of documents as soon as possible but in any event no later than the third business day after the conditions described below under the subsection “— Conditions to Closing of the Transaction” have been satisfied, or, to the extent permitted under applicable law, waived in writing by the party to the Transaction Agreement entitled to the benefit of the same (other than those conditions which by their terms are required to be satisfied at closing, but subject to the satisfaction or, to the extent permitted under applicable law, waiver in writing of such conditions by the party or parties entitled to the benefit of such conditions) or on such other date as Summit and Cementos Argos mutually agree in writing.

The obligations of the parties to consummate the closing of the Transaction is subject to the satisfaction of the following conditions (or, to the extent permitted by applicable law, waiver by each of (i) Summit and (ii) Cementos Argos, on behalf of Cementos Argos, the Argos Parties and Argos USA):

The obligations of Summit to consummate the closing of the Transaction is subject to the satisfaction (or, to the extent permitted by applicable law, waiver by Summit) of the following further conditions:

The obligation of Cementos Argos, Argos USA and the Argos Parties to consummate the closing of the Transaction is subject to the satisfaction (or, to the extent permitted by applicable law, waiver by Cementos Argos on behalf of Cementos Argos, Argos USA and the Argos Parties) of the following further conditions:

Under the Transaction Agreement, Argos USA made customary representations and warranties relating to: existence and power, authorization, government authorization, noncontravention, capitalization, financial statements, absence of certain changes, no undisclosed liabilities, material contracts, taxes, title to and sufficiency of assets, litigation, compliance with laws and court orders, properties, intellectual property, data privacy and security, insurance coverage, licenses and permits, finders’ fees, environmental matters, employees and labor matters, employee benefits, affiliate transactions, FCPA and compliance with office of foreign assets control, accounts receivable, accounts payable and inventory, working capital, trade allowances, product liability, disclosure documents and mineral rights.

Under the Transaction Agreement, the Argos Parties made customary representations and warranties relating to: existence and power, authorization, governmental authorization, noncontravention, ownership of purchased shares, litigation and governmental orders, investment intent, accredited investor and independent investigation, no reliance and disclosure documents.

Under the Transaction Agreement, the Summit parties made customary representations and warranties relating to: existence and power, authorization, governmental authorization, capitalization, noncontravention, litigation, finders’ fees, issuance of shares, absence of certain changes, public filings, financing, financial statements, no undisclosed liabilities, compliance with laws and court orders, FCPA and compliance with office of foreign assets control, taxes and disclosure documents.

Cementos Argos and the Argos Parties, in each case, solely to the extent related to the ANAC Business, and Argos USA made certain covenants under the Transaction Agreement, including, except as required by applicable law or under the Transaction Agreement, set forth in the underlying disclosure schedule or as consented to by Summit in writing (such consent not to be unreasonably withheld, conditioned or delayed), that, prior to the closing of the Transaction, Cementos Argos, the Argos Parties and Argos USA will, and will cause each of its subsidiaries to (i) use their reasonable best efforts to conduct the ANAC Business in the ordinary course in all material respects and, to the extent consistent with the foregoing clause (i), and (ii) use their reasonable best efforts to (A) preserve intact the present business organization of the ANAC Companies and the ANAC Business and (B) keep available the services of the directors and officers of Argos USA, and (C) maintain existing relationships with the customers, lenders, suppliers, lessors and others having material business relationships with the ANAC Business.

Prior to the closing of the Transaction, except as required by applicable law or under the Transaction Agreement, set fort in the underlying disclosure schedule or as consented to by Summit in writing (such consent not to be unreasonably withheld, conditioned or delayed) Argos USA may not, and will cause its subsidiaries not to (and Cementos Argos and the Argos Parties, in each case, solely to the extent related to the ANAC Business, will cause the ANAC Companies not to):

Prior to the closing of the Transaction, except as required by applicable law or under the Transaction Agreement, set forth in the underlying disclosure schedule or as consented to by Cementos Argos in writing (such consent not to be unreasonably withheld, conditioned or delayed), Summit made certain covenants under the Transaction Agreement, including covenants that Summit will, and will cause each of its subsidiaries to (i) use their reasonable best efforts to conduct its business in the ordinary course in all material respects and (ii) use their reasonable best efforts to (A) preserve intact its present business organization and (B) keep available the services of the directors and officers of Summit, and (C) maintain existing relationships with the customers, lenders, suppliers, lessors and others having material business relationships with it.

Subject to certain exceptions, prior to the closing of the Transaction, except as required by applicable law, or under the Transaction Agreement, or as consented to by Cementos Argos in writing (such consent not to be unreasonably withheld, conditioned or delayed), Summit may not, and will cause its subsidiaries not to:

Additionally, until the earlier of the closing of the Transaction and the termination of the Transaction Agreement pursuant to its terms, Summit may not and must cause its subsidiaries not to, consummate or enter into any agreement providing for any investment, acquisition, or other business combination that would reasonably be expected to prevent, enjoin or materially delay the consummation of the closing of the Transaction.

In addition to the above covenants, Summit made certain non-solicitation covenants in respect of a Summit Acquisition Proposal and a Superior Proposal (each as defined below).

During the period from the date of the Transaction Agreement and continuing until the earlier of the termination of the Transaction Agreement pursuant to its terms or the closing, Summit will not, will cause its subsidiaries not to and will instruct its and their respective representatives not to, directly or indirectly:

Prior to the earlier of the termination of the Transaction Agreement pursuant to its terms and the closing of the Transaction, Summit must (i) notify Cementos Argos promptly (and in any event no later than 24 hours) (A) of the receipt by Summit of any Summit Acquisition Proposal (including any bona fide offer, inquiry, proposal or indication of interest with respect to thereto) or any amendment or modification to the material terms of any Summit Acquisition Proposal and such notice must include, to the extent then known to Summit, the identity of the person making the applicable Summit Acquisition Proposal (or bona fide offer, inquiry, proposal or indication of interest with respect to thereto) and the material terms and conditions thereof (along with unredacted copies of all material proposed transaction agreements and other material documents provided in connection therewith) and (B) of any request for nonpublic information relating to Summit or any of its subsidiaries or for access to the business, properties, assets, books or records or personnel of Summit or any of its subsidiaries by any third party that has notified Summit that it is considering making, or has made, a Summit Acquisition Proposal and (ii) keep Cementos Argos reasonably informed on a reasonably current basis (and, in any event, within 24 hours) of any changes to the status and material terms and conditions (along with unredacted copies of all material proposed transaction agreements and other material documents provided in connection therewith, including any amendments thereto) of any Summit Acquisition Proposal (or bona fide offer, inquiry, proposal or indication of interest with respect to thereto).

A “Summit Acquisition Proposal” means, other than the Transaction, any offer or proposal from any third party person or group, relating to, in a single transaction or a series of related transactions, (i) any acquisition or purchase, directly or indirectly, of 20% or more of the consolidated assets of Summit and its subsidiaries or 20% or more of any class of equity or voting securities of Summit and its subsidiaries whose assets, individually or in the aggregate, constitute 20% or more of the consolidated assets of Summit and its subsidiaries, (ii) any tender offer or exchange offer that, if consummated, would result in such third party person or group beneficially owning 20% or more of any class of equity or voting securities of Summit and its subsidiaries whose assets, individually or in the aggregate, constitute 20% or more of the consolidated assets of Summit and its subsidiaries, or (iii) a merger, consolidation, amalgamation, share exchange, business combination, sale of substantially all of the assets, reorganization, recapitalization, liquidation, dissolution or other similar transaction involving Summit and its subsidiaries whose assets, individually or in the aggregate, constitute 20% or more of the consolidated assets of Summit and its subsidiaries.

A “Superior Proposal” means an unsolicited, bona fide, written Summit Acquisition Proposal (but substituting “70%” for all references to “20%” in the definition of such term) that the Board determines in good faith, after consultation with its outside legal counsel and financial advisor, is more favorable from a financial point of view to Summit’s stockholders than the transactions, in each case, taking into consideration (i) all relevant factors, including the identity of the counterparty, the terms and conditions of such Summit Acquisition Proposal (including the transaction consideration, conditionality, timing, certainty of financing and regulatory approvals and the expected timing and likelihood of consummation) and such other factors as determined by the Board in good faith to be relevant and (ii) if applicable, any changes to the terms of the Transaction Agreement proposed by Cementos Argos (pursuant to the non-solicitation provisions of the Transaction Agreement) that, if accepted by Summit, would be binding upon Cementos Argos.

Prior to the Stockholder Approval:

Following the date of the Transaction Agreement, Summit will, and will use reasonable best efforts to cause its subsidiaries and representatives to, immediately cease and cause to be terminated any existing activities, discussions or negotiations with any person conducted with respect to any Summit Acquisition Proposal, or proposal that would reasonably be expected to lead to a Summit Acquisition Proposal.

Each of Cementos Argos, Argos USA, the Argos Parties and Summit will use their respective reasonable best efforts to take, or cause to be taken, all actions and to do, or cause to be done, all things necessary, proper or advisable under applicable laws to consummate the transactions contemplated by the Transaction Agreement, including using reasonable best efforts in:

As promptly after the date of the Transaction Agreement as reasonably practicable, but within 10 business days, each of Summit, Cementos Argos, the Argos Parties and Argos USA will make:

Each Party must (i) keep the other apprised of the status of matters relating to the completion of the transaction and the other transactions contemplated by the Transaction Agreement and work cooperatively in connection with obtaining all required approvals; (ii) promptly notify the other parties of any written communication to that party from the FTC, the Antitrust Division, any State Attorney General or any other governmental authority, and, subject to applicable law, permit the other parties to review and discuss in advance, and consider in good faith the views of the other party in connection with, any proposed written communication to any of the foregoing; (iii) promptly provide all documents requested by the FTC, the Antitrust Division, any State Attorney General or any other governmental authority to the extent reasonably necessary or advisable to obtain as promptly as practicable all required approvals; (iv) promptly consult with the other party to the Transaction Agreement to provide any necessary information with respect to (and, in the case of correspondence, provide the other party (or their counsel) copies of) all filings made by such party with any governmental authority and furnish the other party with such necessary information and reasonable assistance as the other party may reasonably request in connection with its preparation of filings or submissions of information to any such governmental authority; (v) not agree to participate in any substantive meeting or discussion with any governmental authority in respect of any filings, investigation or inquiry concerning any competition or antitrust matters in connection with the Transaction Agreement or the closing of the Transaction unless it consults with the other parties in advance and, to the extent permitted by such governmental authority, gives the other parties the opportunity to attend and participate thereat; and (vi) furnish the other parties with copies of all correspondence, filings, and communications (and memoranda setting forth the substance thereof) between them and their affiliates and their respective representatives on the one hand, and any governmental authority or members or their respective staffs on the other hand, with respect to any competition or antitrust matters in connection with the Transaction Agreement.

The parties to the Transaction Agreement have also (i) agreed to take certain actions with respect to tax matters and (ii) made certain covenants related to, among other things, (a) employee matters, (b) Summit's obligation to use its reasonable best efforts to consummate the Debt Financing (as defined in the Transaction Agreement) and (c) the filing of a proxy statement relating to the Stockholder Approval.

In conjunction with the entry into the Transaction Agreement, Summit entered into a binder agreement for a representation and warranty insurance policy (the “R&W Insurance Policy”), which will be bound by Illinois Union Insurance Company and the other excess insurers at the closing of the Transaction. The R&W Insurance Policy is subject to a limit of liability of $175,000,000 in the aggregate, a retention amount of $16,000,000 in the aggregate for all claims except for certain exclusions, deductibles and other terms and conditions set forth therein.

Subject to the limitations set forth below under “—Survival of Representations,” and subject to the subrogation rights of the Argos Parties under the Transaction Agreement and the R&W Insurance Policy at and after the closing, Cementos Argos and the Argos Parties will, jointly and severally, indemnify Summit, each ANAC Company and each of their respective officers, directors, employees, affiliates and agents and each of their respective successors and permitted assigns (collectively, the “Summit Indemnified Parties”) against and agrees to defend and hold each of them harmless from any and all damages, incurred or suffered by any Summit Indemnified Party (regardless of whether the damages arise as a result of the negligence, strict liability, or other liability under any theory of law or equity of any person and whether involving a third-party claim or claims solely between the parties) arising out of, relating to or resulting from or under:

Except with respect to claims of Fraud, the maximum aggregate amount of indemnifiable damages that may be recovered from Cementos Argos or any Argos Party pursuant to these indemnification provisions is $3,170,000,000.

Under the Transaction Agreement, Summit will indemnify Cementos, each Argos Party and each of their respective officers, directors, employees, affiliates (other than the ANAC Companies) and agents and each of their respective successors and permitted assigns (collectively, the “Argos Party Indemnified Parties”) against and will defend hold each of them harmless from any and all damages, incurred or suffered by such Argos Party Indemnified Party (regardless of whether such damages arise as a result of the negligence, strict liability, or other liability under any theory of law or equity of any Person and whether involving a third-party claim or claims solely between the Parties) arising out of, relating to or resulting from or under:

Except with respect to claims of Fraud, the maximum aggregate amount of indemnifiable damages that may be recovered from Summit pursuant to these indemnification provisions is $3,170,000,000.

The Transaction Agreement may be terminated notwithstanding any approval of the Transaction Agreement by the equityholders of Argos USA or the stockholders of Summit, as follows:

The Transaction Agreement provides for certain payments if the Transaction Agreement is terminated for specified reasons, including:

While Cementos Argos may pursue both a grant of specific performance and the payment of the Summit Termination Fee, Cementos Argos is not permitted or entitled to receive both a grant of specific performance that results in the closing and any money damages, including all or any portion of the Summit Termination Fee.

Summit and Cementos Argos agree that (a) irreparable damage would occur if any provision of the Transaction Agreement were not performed in accordance with the terms thereof, (b) the parties will be entitled to an injunction or injunctions to prevent breaches or threated breaches of the Transaction Agreement or to enforce specifically the performance of the terms and provisions thereof in the Delaware Court of Chancery and any state appellate court therefrom within the State of Delaware, in addition to any other remedy to which they are entitled at law or in equity, (c) the provisions of Section 11.03 of the Transaction Agreement would not adequately compensate the non-breaching party for the harm that would result from a breach of the Transaction Agreement by the breaching party and will not be construed to diminish or otherwise impair in any respect any party’s right to an injunction, specific performance and other equitable relief and (d) the right to specific performance is an integral part of the Transaction Agreement and without that right, neither party would have entered into the Transaction Agreement.

For certain regulatory reasons, it is important that Cementos Argos’s voting interest is not involuntarily diluted below 25.01% of the Common Stock. As a result, Summit agreed to issue the Preferred Share at the closing in order to provide Cementos Argos with a short window in which Cementos Argos will have the ability to purchase shares of Class A Common Stock in the market, in certain limited circumstances, to prevent Cementos Argos from being involuntarily diluted below 25.01%. Pursuant to the terms and conditions of the Transaction Agreement, Summit will prepare a Certificate of Designation, in a form reasonably satisfactory to Cementos Argos, for the Preferred Share. The Certificate of Designation will include, among other rights, privileges and restrictions, that the Preferred Share:

“Preferred Voting Window” means the period commencing on the date immediately preceding the consummation of an M&A Issuance (as defined below) and ending 90 Trading Days (as defined below)

thereafter, but only if (i) at all times following the closing date until immediately prior to the consummation of such M&A Issuance, Investor Anchor maintained a voting interest in excess of 25.00%, or at any time Investor Anchor did not, had Top-Up Rights (as defined below) that would allow Investor Anchor to exceed the 25.00% Threshold during any associated Trading Period, (ii) the M&A issuance identified in the Transaction Notice (as defined below) would reasonably be expected to result in Grupo Argos being deemed, on or about the date of the Triggering Event (as defined below), an “investment company” for purposes of the Investment Company Act of 1940 (the “Investment Company Act”) (taking into account any exemptions or exceptions that may be available thereunder, including the exception set forth in Rule 3a-2 thereunder but excluding any exemption under Section 3(b) of the Investment Company Act), (iii) Investor Anchor has present intent to purchase additional shares of Class A Common Stock after the closing of the transaction contemplated in the Transaction Notice, in order to ensure that its voting interest will be in excess of 25.00%, but subject to the other limitations set forth in the Stockholder Agreement, and (iv) Summit does not make an M&A Anti-Dilution Offer (as defined below) in accordance with the applicable section of the Stockholder Agreement; provided that, the Preferred Voting Window shall immediately and automatically terminate, with no further action on the part of any person, if Investor Anchor Transfers (as defined in the Stockholder Agreement, but without giving effect to clause (iii) in the proviso thereof), any Voting Securities at any time from the date on which the Board approves the M&A Issuance until the date that is the end of such Preferred Voting Window.

This section describes certain additional agreements to be entered into pursuant to the Transaction Agreement, but does not purport to describe all of the terms thereof. The following summary is qualified in its entirety by reference to the complete text of each of the agreements. Forms of the Stockholder Agreement, the Registration Rights Agreement term sheet, the Restrictive Covenants Agreement, the Transition Services Agreement, the Support Services Agreement, the Cement Supply Agreement, the Intellectual Property License Agreement, the Logistics Agreement (Cartagena), the Master Purchase Agreement and the Logistics Agreement (International) are attached hereto as Annexes B through J. You are urged to read such agreements in their entirety prior to voting on the proposals presented at the Special Meeting.

Subject to and effective upon the consummation of the Transaction, Summit will enter into the Stockholder Agreement with Cementos Argos, Argos SEM, Valle Cement and, solely for the purpose of specified sections of the Stockholder Agreement, Grupo Argos.

Pursuant to the Stockholder Agreement, as of immediately following the closing of the Transaction, the Board will be comprised of eleven or fewer directors, including three Investor Nominees designated by Cementos Argos, who will be appointed to the Board at the closing; provided that, in each case, such nominee is an “Acceptable Person” (as defined in the Stockholder Agreement).

Pursuant to the Stockholder Agreement, Summit will agree, at any Stockholder Meeting, to nominate:

From the closing until the date on which Investor Anchor beneficially owns fewer than 5% of the then-outstanding shares of Class A Common Stock (such date, the “Board Designation Expiration Date”), Summit will take all “Necessary Actions” (as defined in the Stockholder Agreement) to cause the Board to reflect the Board composition contemplated by the Stockholder Agreement, including the following:

Neither Summit nor the Board will be under any obligation to nominate or appoint to the Board, or solicit votes for, any person that (i) is not an Acceptable Person, or (ii) to the extent such person is nominated by Cementos Argos as an Independent Director, any such Person that is not an Independent Director. If at any time following an Investor Nominee’s appointment to the Board, any of the events specified in clause (i) or (ii) or the immediately preceding sentence, then Cementos Argos will cause such Investor Nominee to promptly resign from the Board. Without limiting the applicable rights of Cementos Argos under the Stockholder Agreement, Cementos Argos will consult in good faith with the chairman of the Governance and Sustainability Committee regarding Summit’s efforts to maintain an overall board composition, including in respect of any minority groups, that complies with any best practices or guidelines contained in Summit’s governance guidelines or issued by proxy advisor firms of recognized national standing (e.g. Glass Lewis & Co., LLC and Institutional Stockholder Services Inc.).

If Summit amends its certificate of incorporation to provide that the Board will be classified into separate classes of directors, then proper provision will be made such that the designees of Cementos Argos will be distributed as evenly as possible among such classes of directors in order to preserve the designation rights of Cementos Argos in accordance with the Stockholder Agreement.

If Summit increases the size of the Board such that the Board has greater than eleven directors and Investor Anchor continues to beneficially own shares of Class A Common Stock equal to or greater than the 25% Threshold, the number of Investor Nominees that Cementos Argos will be entitled to designate will be increased to the minimum extent necessary so that Investor Nominees constitute more than 25% of the total number of directors on the Board; provided, that Summit will use its commercially reasonable efforts to appoint any additional Investor Nominees that Cementos Argos will be entitled to designate simultaneously with the Board size expansion and concurrently with Summit’s appointment of any other director to the Board.

Following the Board Designation Expiration Date, (i) Cementos Argos will not have the right to designate any Investor Nominee to the Board, and (ii) Summit will not be obligated to nominate Investor Nominees to the Board at any Stockholder Meeting and will have no further obligations under Article III of the Stockholder Agreement (relating to corporate governance and board committee representation).

At any time Investor Anchor beneficially owns greater than 5.0% of the then-outstanding shares of Class A Common Stock (the “5% Threshold”), each committee of the Board (other than any special committee formed solely for the purpose of evaluating a transaction with or primarily involving Grupo Argos, Cementos Argos or any of its affiliates) will include, at Cementos Argos’s election, at least (i) one Investor Nominee selected by Cementos Argos serving as a member of such committee, in each case, subject to any limitations or guidelines imposed by applicable law, Summit’s governance guidelines, any stock exchange rules, including, in the case of the Human Capital and Compensation Committee, Audit Committee and Governance and Sustainability Committee, the requirement that the members of such committee consist solely of Independent Directors, or

(ii) one Investor Nominee selected by Cementos Argos participating as a non-voting observer of such committee; provided that, if the Investor Nominee is not an Independent Director and the inclusion of such Investor Nominee on the Audit Committee would reasonably be expected to have an adverse impact on Summit (including as a result of a negative response from any governmental entities), implementation of the foregoing rights will be subject to the parties’ good faith discussion of an alternative arrangement to ensure that Investor Nominees have the opportunity to provide input on the matters addressed by such committees.

In connection with any search for new candidates to serve as the Chief Executive Officer and Chief Financial Officer of Summit, the Board will create a three person search committee (the “Search Committee”), and the composition of the Search Committee will comply with the applicable terms of the Stockholder Agreement. Any selection of a candidate or other action by the Search Committee will require the affirmative vote of a majority of the directors on the Search Committee.

Pursuant to the Stockholder Agreement, for any Stockholder Meeting following the closing at which Cementos Argos seeks to elect an Investor Nominee, Cementos Argos will provide written notice to Summit of its proposed Investor Nominees no later than 35 days prior to the advance notice deadline (such deadline, the “Advance Notice Deadline”) set forth in Article II, Section 3, of Summit’s Third Amended and Restated Bylaws (the “Bylaws”), as amended from time to time; provided that, if Cementos Argos fails to provide such written notice by the Advance Notice Deadline, Summit will nominate the Investor Nominees then serving on the Board, so long as they continue to qualify as Acceptable Persons and have consented to serve on the Board and be named in Summit’s proxy statement for such Stockholder Meeting.

Promptly following the end of a period beginning on the trading day following a Top-Up Event (as defined below) and ending on the date following which at least 90 trading days have occurred (a “Trading Period”) after a Top-Up Event, Cementos Argos will cause the applicable number of Investor Nominees (if any) to promptly tender their resignations from the Board and any committee of the Board on which such Investor Nominees then sit to the extent necessary to ensure that the number of Investor Nominees then serving on the Board do not exceed the number of Investor Nominees that Cementos Argos would then be entitled to designate for nomination.

“Top-Up Event” means (i) any issuance of voting securities by Summit that results in a reduction of Investor Anchor’s voting interest (for the avoidance of doubt, excluding any sale, disposal or transfer of shares of voting securities by Anchor Investor) (an “Involuntary Top-Up Event”) or (ii), (a) at any time Investor Anchor beneficially owns shares of Class A Common Stock in excess of the 25% Threshold, any sale, disposal, or transfer by Investor Anchor that results in Investor Anchor beneficially owning greater than 20% of the then-outstanding shares of Class A Common Stock but less than or equal to the 25% Threshold, (b) at any time Investor Anchor beneficially owns shares of Class A Common Stock in excess of the 17.5% Threshold (but less than the 25% Threshold), any sale, disposal, or transfer by Investor Anchor that results in Investor Anchor beneficially owning greater than 12.5% of the then-outstanding shares of Class A Common Stock but less than or equal to the 17.5% Threshold and (c) at any time Investor Anchor beneficially owns shares of Class A Common Stock in excess of the 5% Threshold (but less than the 17.5% Threshold), any sale, disposal, or transfer by Investor Anchor that results in Investor Anchor beneficially owning any then-outstanding shares of Class A Common Stock but less than or equal to the 5% Threshold (a “Voluntary Top-Up Event”).

Should any Investor Nominee resign from the Board or be rendered unable to, or refuse to, be nominated or appointed to, or to serve on, the Board, whether due to the death, retirement, disqualification or removal from office as a member of the Board or otherwise, (i) Cementos Argos will be entitled to designate a replacement who is an Acceptable Person for each such Investor Nominee (and if such proposed designee is not an Acceptable Person, Investor shall be entitled to continue designating a replacement until such proposed designee is an Acceptable Person) (a “Replacement”), and (ii) Summit will take all Necessary Action to fill any such vacancy with such Replacement as promptly as reasonably practicable (and in any event no later than the second regularly scheduled Board meeting following the time the Investor designates a Replacement), including appointing such Replacement to the Board in place of the resigning Investor Nominee. Summit and the Board will have no obligation to reschedule any Board meeting or to otherwise delay any Board action on any matter prior to such appointment.

Each Investor Nominee will be entitled to the same expense reimbursement and advancement, exculpation and indemnification in connection with his or her role as a director as the other members of the Board, as well as reimbursement for reasonable and documented out-of-pocket expenses incurred in attending meetings of the Board or any committee of the Board of which such Investor Nominee is a member, if any, in each case to the same extent as the other members of the Board. Each Investor Nominee will also be entitled to any retainer, equity compensation or other fees or compensation paid to the non-employee directors of Summit for their services as a director, including any service on any committee of the Board. Each Investor Nominee will be entitled to the same directors’ and officers’ insurance coverage as the other directors of the Board. Summit will promptly enter into an indemnification agreement with each Investor Nominee in the same form and substance as those of the other directors of the Board, and will offer to enter into any amendments or successor arrangements with each Investor Nominee on a non-discriminatory basis to the extent offered to other directors of the Board.

From and after the date of the Stockholder Agreement until the date that no Investor Nominee is entitled to serve on the Board (the “Standstill Period”), without Summit’s prior written consent, Grupo Argos, Cementos Argos and each Investor Participant will not, and will cause each of their respective controlled affiliates and will direct their representatives acting on their behalf not to, directly or indirectly:

Notwithstanding anything to the contrary in Stockholder Agreement, (i) no action or activity required or otherwise expressly contemplated to be taken by Cementos Argos or its affiliates or an Investor Nominee under the Stockholder Agreement or the Transaction Agreement or any exhibit thereto will be or be deemed to be restricted by or subject to the prohibitions set forth in the Stockholder Agreement; (ii) the Stockholder Agreement will not prevent or restrict the ability of Cementos Argos or any of its affiliates from (A) making any confidential proposal to Summit or the Board, so long as the making or receipt of such proposal would not reasonably be expected to require Summit, Grupo Argos, Cementos Argos or any of their respective affiliates to make any public disclosure; and (B) participating as a potential purchaser (on the same terms, and subject to the same conditions, as other potential purchasers) in any process, bilateral negotiation or otherwise pursuant to which Summit provides confidential information to, or enters into negotiations with, a third party relating to a change of control on the terms and conditions established by the Board for such process; it being understood that (x) Cementos Argos will provide prompt written notice (a “Sale Process Notice”) to Summit of Cementos Argos’s intent to participate in such process or negotiation (as applicable) within fifteen business days of Cementos Argos’s receipt of Summit’s notice in respect of any such process or negotiation, and (y) the restrictions set forth in the applicable section of the Stockholder Agreement will remain in effect notwithstanding Summit’s entry into a process or negotiation with a third party relating to a change of control, including if Summit executes a definitive agreement relating to such change of control and/or recommends to the stockholders of Summit any third party tender offer or exchange offer for equity securities that would result in a change of control. If Cementos Argos provides a Sale Process Notice to Summit, Cementos Argos will, and will cause any Investor Nominee to (as applicable), (x) promptly recuse themselves from any Board (or any committee thereof) meeting involving or relating to such process or negotiation (as applicable), and (y) except at the invitation of the Board, not communicate with, participate in, or otherwise seek to affect the outcome of, discussions and votes of the Board (or any committee thereof) with respect to any matters coming before it in respect of such process or negotiation (as applicable). Notwithstanding anything to the contrary provided in the Stockholder Agreement, Cementos Argos, Grupo Argos and their respective controlled affiliates will not be restricted from making any disclosure that such party determines in good faith, and on the advice of counsel, is required pursuant to applicable law.

If after the date the Stockholder Agreement is executed, any Top-Up Event occurs:

Notwithstanding anything to the contrary, nothing in the Stockholder Agreement will (x) restrict a party with Top-Up Rights from simultaneously or consecutively exercising such Top-Up Rights arising out of a Voluntary Top-Up Event and an Involuntary Top-Up Event, or (y) permit any person to exercise Top-Up Rights to the extent Investor Anchor would beneficially own equity securities or derivative instruments in excess of the Cap.

From and after the date of execution of the Stockholder Agreement until the date that no Investor Nominee is entitled to serve on the Board, Cementos Argos and each Investor Participant will (and Cementos Argos will cause each such Investor Participant to) cause all equity securities beneficially owned by Cementos Argos, each Investor Participant and their respective affiliates, as of the record date for any Stockholder Meeting, including for the avoidance of doubt all shares of Class A Common Stock that may be taken into account for purposes of calculating an applicable threshold, to be present for quorum purposes and to be voted, at all such Stockholder Meetings or at any adjournments or postponements thereof, (i) in favor of all directors nominated by the Board in all non-contested director elections, so long as Summit complies with its obligations under Article III of the Stockholder Agreement, (ii) in all contested director elections, at the election of Cementos Argos, either (A) in favor of directors nominated by the Board, or (B) in the same proportion as all other votes cast (such proportion determined without inclusion of the votes cast by Grupo Argos, Cementos Argos, each Investor Participant and their respective affiliates), and (iii) for all other matters, in their discretion, except that, to the extent Grupo Argos, Cementos Argos, each Investor Participant and their respective affiliates beneficially own voting interests representing more than 25.01%, such persons will vote such excess in the same proportion as all other votes cast (such proportion determined without inclusion of the votes cast by Grupo Argos, Cementos Argos, each Investor Participant and their respective affiliates).

Except to the extent expressly contemplated by the applicable section of the Stockholder Agreement, following the execution of the Stockholder Agreement and at any time when the 25% Threshold is satisfied, without the prior written consent of Cementos Argos (not to be unreasonably withheld, conditioned, or delayed), Summit and its subsidiaries will not:

The parties to the Stockholder Agreement acknowledge and agree that Summit may obtain any consent required pursuant to the Stockholder Agreement by sending written notice (email being sufficient), which will include the request and reasonable explanation therefor, to the Chief Executive Officer and the Chief Legal Officer of Cementos Argos in accordance with the Stockholder Agreement. Cementos Argos will cause such persons to promptly respond in writing to any such written notice. If Summit does not receive a written response from such persons within five business days of Summit’s delivery of any written notice, Cementos Argos will be deemed to have consented to any matter set forth in such written notice.

Summit’s annual budget will be reviewed and approved by the Board.

From the date of the Stockholder Agreement until such time as the 5% Threshold is not satisfied, Cementos Argos will have the right to purchase up to its voting interest of any equity securities that Summit may from time to time propose to issue or sell, for cash or cash equivalents (a “Capital Raising Transaction”), to any person (any such securities proposed to be issued or sold to any person, the “Proposed Securities”) at a purchase price per Proposed Security equal to the exercise price and on the same economic terms and conditions and with the same voting rights as such Proposed Securities are sold to others by delivering a written notice to Summit (the “Capital Raising Anti-Dilution Right”).

Summit will give written notice to Cementos Argos (an “Issuance Notice”) of any proposed issuance or sale of Proposed Securities no later than (i) in the case of a Capital Raising Transaction that is an underwritten public offering or a private offering made to “Qualified Institutional Buyers” (as such term is defined in Rule 144A under the Securities Act) or “non-U.S. Persons” (as such term is defined under Rule 902(k) under the Securities Act) for resale pursuant to Rule 144A or Regulation S under the Securities Act, twenty business days prior to the launch of such offering and (ii) in the case of any other Capital Raising Transaction, no later than twenty business days prior to the proposed issuance or sale date. The Issuance Notice will set forth the following terms and conditions of the proposed issuance or sale:

Cementos Argos’s pre-emptive right will be exercisable by delivery of a written notice by Cementos Argos to Summit no later than the tenth business day following receipt of any Issuance Notice (the “Capital Raising Issuance Deadline”), specifying the number of Proposed Securities to be purchased by Cementos Argos in connection with such Capital Raising Transaction, which written notice will, except to the extent expressly contemplated by the Stockholder Agreement, constitute a binding agreement of Cementos Argos to purchase such number of Proposed Securities at the exercise price and on the same economic terms and conditions as such Proposed Securities are sold to others (the “Capital Raising Acceptance Notice”).

In the event that a definitive agreement or any amendment thereof executed by Summit providing for any Capital Raising Transaction (a “Capital Raising Definitive Agreement”) contains a different exercise price or a material difference in any other material term or condition set forth in the Issuance Notice, then Summit will deliver to Cementos Argos on the date that Summit executes such Capital Raising Definitive Agreement an updated Issuance Notice, which will include a reasonable description of such differences and, in that case, the Capital Raising Issuance Deadline will be forty-eight hours following the date on which Cementos Argos receives such updated Issuance Notice.

The closing of any purchase by Cementos Argos will be consummated concurrently with the consummation of the Capital Raising Transaction; provided, that any such closing will be extended beyond the closing of the Capital Raising Transaction to the extent necessary (i) to obtain any required approval of a governmental entity or (ii) to the extent stockholder approval is required under the applicable stock exchange rules, in which case Summit and Cementos Argos will use their respective reasonable best efforts to obtain any such approval(s). If Cementos Argos will not have delivered a Capital Raising Acceptance Notice to Summit by the Capital Raising Issuance Deadline, Cementos Argos will be deemed to have waived all of its rights under the applicable section of the Stockholder Agreement with respect to the purchase of the Proposed Securities in such Capital Raising Transaction.

In the event that Cementos Argos fails to exercise the Capital Raising Anti-Dilution Right by the Capital Raising Issuance Deadline, Summit will thereafter be entitled during the period of ninety days following the conclusion of the applicable prescribed period (the “Sale Period”) to sell the equity securities not elected to be purchased by Cementos Argos (i) at a price that is not 10% less than the exercise price and (ii) upon other terms and conditions (such terms and conditions, other than price, the “Terms and Conditions”) not materially more favorable in the aggregate to the purchasers of such equity securities than those offered to Cementos Argos, as determined in good faith by the Board (a “Third Party Issuance”). In the event Summit has not sold such Equity Securities within the Sale Period, Summit will not thereafter issue or sell such equity securities without first offering such equity securities to Cementos Argos in the manner provided in the Stockholder Agreement. If such Third Party Issuance is subject to regulatory approval, the Sale Period in respect of such Third Party Issuance will be extended until the expiration of five Business Days after all such approvals have been received, but in no event later than 270 days from the date of the Issuance Notice.

The pre-emptive rights provided for in the Stockholder Agreement will not apply to any issuances of equity securities by Summit (i) to its directors or employees for compensatory purposes pursuant to an equity incentive plan approved by the Board, (ii) as consideration in a bona fide direct or indirect merger, acquisition, strategic transaction, partnership or alliance or similar transaction that is approved by the Board or any other strategic or commercial transaction that is approved by the Board in which Summit issues equity securities, or (iii) in connection with any pro rata stock split, combination, stock dividend, recapitalization, reorganization or any similar transaction in each case, in which the voting and economic rights of the shares of Class A Common Stock are preserved.

From the date of the execution of the Stockholder Agreement until the date that no Investor Nominee is entitled to serve on the Board, the Board will take Necessary Action to cause the exemption of the exercise of the Capital Raising Anti-Dilution Right and the “M&A Anti-Dilution Right” (as defined below) by Cementos

Argos or any of its affiliates or any other acquisitions of equity securities by Cementos Argos or any of its affiliates from Summit or any of its subsidiaries that are permitted by the terms of the Stockholder Agreement from the liability provisions of Section 16(b) of the Exchange Act pursuant to Rule 16b-3.

If Summit or any of its subsidiaries proposes to enter into or consummate any holding company reorganization or other similar transaction that would reasonably be expected to frustrate the purpose of the Capital Raising Anti-Dilution Right, Summit and Cementos Argos will negotiate in good faith to modify the terms of the Capital Raising Anti-Dilution Right to the extent necessary to preserve their intent and purpose.

Notwithstanding the foregoing, in connection with any issuance of equity securities by Summit (but solely at a time when the 5% Threshold is satisfied) (such issuance, the “M&A Issuance”), Summit will give written notice to Cementos Argos of any such proposed issuance upon the earlier of (1) four business days after the announcement of such transaction and (2) thirty (30) days prior to the date of the proposed issuance (a “Transaction Notice”), which written notice will contain the information set forth in the applicable section of the Stockholder Agreement. Following the issuance of equity securities contemplated by such Transaction Notice, Investor Anchor will not be prohibited from acquiring, agreeing to acquire, proposing or offering to acquire, or seeking to acquire any shares of Class A Common Stock, and each such person will be expressly permitted to take such actions, with respect to a sufficient number of shares of Class A Common Stock in order to reverse the effect of any dilution to the voting interest of Investor Anchor resulting from the issuance of the equity securities contemplated by the Transaction Notice (the “Open Market Purchase Right”). Solely to the extent (a) Summit’s issuance of equity securities specified (or that should have been specified) in a Transaction Notice could reasonably be expected to cause Investor Anchor to beneficially own fewer shares of Class A Common Stock than the 25% Threshold (after giving effect to such issuance), assuming for this purpose that Investor Anchor had exercised all Top-Up Rights for each prior Top-Up Event for which the applicable Trading Period has not yet ended as of such time, (b) Cementos Argos has determined that, based on the advice of counsel, the issuance of equity securities contemplated by the transaction identified in the Transaction Notice would reasonably be expected to result in Grupo Argos being deemed, on or about the date of the Triggering Event (as defined below), an “investment company” for purposes of the Investment Company Act (taking into account any exemptions or exceptions that may be available thereunder, including the exception set forth in Rule 3a-2 thereunder but excluding any exemption under Section 3(b) of the Investment Company Act), and (c) Investor Anchor has the present intent to purchase additional shares of Class A Common Stock after the closing of the transaction contemplated in order to ensure that its voting interest will be in excess of 25%, but subject to the other limitations set forth herein ((a), (b) and (c) together, a “Triggering Event”), Cementos Argos may, within five business days following delivery of a Transaction Notice, deliver notice to Summit, certified to by an officer of Cementos Argos solely in their capacity as such, that a Triggering Event has occurred (a “Triggering Notice”). Summit may, in its sole discretion, deliver a written offer to Cementos Argos to sell to Cementos Argos the number of shares of Class A Common Stock needed in order to cause Investor Anchor to have a voting interest of at least 25.01%, or, if Summit and Investor Anchor agree, to reverse the effect of any dilution to the voting interest of Investor Anchor resulting from the issuance of the equity securities contemplated by the Transaction Notice (“M&A Dilution Issuance”), at a purchase price equal to the volume-weighted average trading price of a share of Class A Common Stock on the NYSE (as reported by Bloomberg L.P.) for the 30 trading days immediately prior to the day that is two business days prior to the closing of such issuance on an as-is where-is basis, with representations from Summit limited to customary fundamental representations as to corporate power and authority and transfer of good and valid title to the shares of Class A Common Stock being sold (the “M&A Anti-Dilution Right”). Cementos Argos may exercise its M&A Anti-Dilution Right to purchase all, but not less than all, of the M&A Dilution Issuance by delivery of written notice by Cementos Argos to Summit no later than 10 business days following the delivery of an M&A Anti-Dilution Offer.

To the extent that, with respect to any anticipated M&A Issuance, stockholder approval is required under the applicable stock exchange rules and/or governmental entity approval is required, each of Summit and Investor Anchor will use reasonable best efforts to obtain such approval(s) prior to the closing of the M&A Issuance, which reasonable best efforts will include, in the case of Investor Anchor, causing (i) all shares of Class A Common Stock beneficially owned by Investor Anchor to be present for quorum purposes at any Stockholder Meeting or any adjournments or postponements thereof at which approval in respect of the M&A Issuance and/or the M&A Dilution Issuance is sought, and (ii) to be voted, at such Stockholder Meetings or at any adjournments or postponements thereof, in favor of any proposal in respect of the M&A Issuance and/or the M&A Dilution Issuance. Summit will use reasonable best efforts to ensure that the closing of any M&A Dilution Issuance will

be consummated concurrently with the consummation of the M&A Issuance. Following the timely delivery of an M&A Anti-Dilution Offer, if Cementos Argos does not deliver a written notice exercising Cementos Argos’s M&A Anti-Dilution Right to Summit within the time period specified above or otherwise materially breaches the applicable terms and conditions of the Stockholder Agreement, then (x) the M&A Anti-Dilution Right in respect of such M&A Issuance is deemed to be waived, and (y) the Triggering Event will be deemed to have not occurred solely for purposes of the Summit preferred stock.

If Investor Anchor ceases to beneficially own, in the aggregate, Class A Common Stock equal to or greater than the 25% Threshold and no longer has Top-Up Rights that would allow it to exceed the 25% Threshold, notwithstanding anything contained in the applicable section of the Stockholder Agreement, Summit may issue equity securities without first complying with the applicable provisions of the Stockholder Agreement; provided that (i) Summit gives prompt written notice to Cementos Argos specifying the material terms of the issuance, and (ii) Summit takes all steps reasonably necessary to enable Cementos Argos to effectively exercise its rights under the Stockholder Agreement with respect to the purchase of its voting interest of the Proposed Securities issued as promptly as reasonably practicable (and in any event within 60 days) following such issuance on the terms specified in the Stockholder Agreement.

Investor Anchor agrees to use reasonable best efforts to provide written notice to Summit promptly (and in any event within five business days) following Investor Anchor’s use of the exception set forth in Rule 3a-2 of the Investment Company Act of 1940.

Summit agrees to use reasonable best efforts to provide written notice to Cementos Argos and, if it is part of Investor Anchor, Grupo Argos promptly following the last day of each calendar month stating the number of voting securities outstanding as of the last trading day of each calendar month, based on the information then-available from Summit’s transfer agent.

From the execution date of the Stockholder Agreement until such time as Investor Anchor ceases to beneficially own any shares of Class A Common Stock, if Summit initiates any share repurchase program or offer to repurchase any shares of Class A Common Stock for a price per share of Class A Common Stock equal to or in excess of the closing price per share of Class A Common Stock on the closing date (such price to be equitably adjusted to the extent necessary to provide the parties the same economic effect as contemplated prior to any stock split, reverse stock split, stock dividend, reorganization, reclassification, combination, recapitalization or other like change), including pursuant to (i) any tender offer or exchange offer subject to Section 13(e) or Section 14(e) of the Exchange Act, or (ii) any other offer available to substantially all holders of shares of Class A Common Stock to purchase or exchange their shares, then, (x) if not participating in such share repurchase would result in Grupo Argos, Cementos Argos, each Investor Participant and each of their respective affiliates beneficially owning equity securities or derivative instruments in excess of the Cap, and (y) the Board has taken such actions as may be reasonably necessary to exempt such share purchase under Rule 16-3(e) under the Exchange Act as contemplated below, Grupo Argos, Cementos Argos, each Investor Participant and each of their respective affiliates will participate in any such share repurchase and tender any shares of Class A Common Stock beneficially owned by such persons in order to maintain their voting interest as of immediately prior to such share repurchase (an “Investor Share Repurchase”); provided, that if Summit determines that withholding is required (including, for the avoidance of doubt, pursuant to Section 1445 of the Code) from amounts otherwise payable to Grupo Argos, Cementos Argos, each Investor Participant and each of their respective affiliates pursuant to an Investor Share Repurchase, then at least five business days prior to making any such deduction or withholding, Summit will provide notice to Cementos Argos of the amounts subject to withholding and will cooperate with Grupo Argos, Cementos Argos, each Investor Participant and each of their respective affiliates, as applicable, to eliminate or minimize to the greatest extent practicable the basis for such deduction or withholding. In connection with any Investor Share Repurchase, the Board will take such actions as may be reasonably necessary to exempt such Investor Share Repurchase under Rule 16b-3(e) under the Exchange Act.

Under the Stockholder Agreement, none of Grupo Argos, Cementos Argos or any of their respective affiliates (including any Investor Participant) will (and Grupo Argos and Cementos Argos will cause any such person not to), transfer any shares of Class A Common Stock (the “Covered Shares”) without Summit’s prior written consent prior to the Lock-Up Termination Date, other than Transfers pursuant to the Stockholder Agreement.

Notwithstanding the foregoing, the restrictions set forth above will not apply to (i) transfers to Grupo Argos or any controlled affiliate of Grupo Argos or Cementos Argos, in each case, that has agreed to be bound by the terms of the Stockholder Agreement as an Investor Participant by executing and delivering a counterpart to the Stockholder Agreement in the form attached thereto as Exhibit A prior to such transfer (provided that, the transferor will continue to be liable under the Stockholder Agreement for any failure of the transferee to comply with any provisions of the Stockholder Agreement), and (ii) any transfers made in connection with (A) any tender offer or exchange offer, in each case, unless the Board recommends against such offer or (B) any merger, consolidation or other similar transaction approved by the Board or Summit.

Following the Lock-Up Termination Date, any Investor Participant may transfer all or any portion of the Covered Shares without Summit’s prior written consent (i) to (a) any person that is not engaged in the construction materials industry with substantial construction materials business or operations in the “Restricted Territory” (as defined in the Stockholder Agreement), or (b) any person, if such person would beneficially own more than 10% of the issued and outstanding shares of Class A Common Stock (together with any other equity securities or derivative instruments of Summit) after giving effect to such transfer (collectively, a “Restricted Transferee”), (ii) to any registered institutional investor principally engaged in the business of managing investment funds for unaffiliated securities investors that is an “accredited investor” within the meaning of Regulation D of the Securities Act, (iii) in connection with a widely-distributed underwritten public offering of any shares of Class A Common Stock or (iv) in sales pursuant to Rule 144 in which such Investor Participant does not have knowledge that the counterparty is a Restricted Transferee.

Subject to the exercise of any rights contemplated by the applicable section of the Stockholder Agreement, the restrictions set forth above will no longer apply on the first date immediately following the end of the Trading Period beginning on the date that no Investor Nominee is entitled to serve on the Board.

Notwithstanding anything else to the contrary in the Stockholder Agreement, neither Cementos Argos, Grupo Argos, nor their respective affiliates may assign any rights, remedies, obligations or liabilities specifically granted to such person under the Stockholder Agreement (including any consent rights and any board designation rights) to any person other than to Grupo Argos or any of its controlled affiliates, and no such rights, remedies, obligations and liabilities will inure to the benefit of any such person, in each case, other than any successors of Cementos Argos or its controlled affiliates. For the avoidance of doubt, no person other than Cementos Argos and any of its controlled affiliates) may exercise any rights or remedies under the Stockholder Agreement.

Except to the extent expressly contemplated by the Stockholder Agreement, the Stockholder Agreement will terminate one year after the first date on which Investor Anchor ceases to beneficially own greater than 5% of the then-outstanding shares of Class A Common Stock, subject to certain exceptions.

Subject to and effective upon the consummation of the Transaction, Summit, Cementos Argos and each Investor Participant will enter into a Registration Rights Agreement, pursuant to which, among other matters, subject to certain limited exceptions, Cementos Argos and each Investor Participant will be granted certain customary shelf, demand and “piggy-back” registration rights with respect to their shares of Class A Common Stock.

Pursuant to the Registration Rights Agreement, following the Lock-Up Termination Date and no later than 60 days after a written request by Cementos Argos or an Investor Participant, Summit will (i) prepare and file with the SEC a shelf registration for the Registrable Securities (as defined in the Registration Rights Agreement) on (a) Form S-3 or a successor form (any such form, a “Form S-3”), if Summit is then eligible to file a registration statement on Form S-3 (“S-3 Eligible”), or (b) if Summit is not then S-3 Eligible, any other appropriate form under the Securities Act for the type of offering contemplated by Cementos Argos or (ii) use an existing Form S-3 filed with the SEC, in each case providing for an offering to be made on a delayed or continuous basis pursuant to Rule 415 under the Securities Act or any successor rule thereto, which in each case of (i) and (ii) covers all Registrable Securities then outstanding held by Cementos Argos, its affiliates and their

permitted assignees for an offering to be made on a delayed or continuous basis pursuant to Rule 415 under the Securities Act or any successor rule thereto. If at the time of such request Summit is a well-known seasoned issuer, such shelf registration shall, upon the approval of the Board, cover an unspecified number of registrable securities to be sold thereunder.

Each of Cementos Argos and each Investor Participant will be entitled to four demand registrations on Form S-1 (and an unlimited number on Form S-3, but any underwritten registration on Form S-3 will count as a demand registration on Form S-1 by any such person if undertaken as an underwritten offering at its demand at a time when Form S-3 is available to Summit); provided that Cementos Argos and each Investor Participant is limited to no more than two underwritten demand registrations in any calendar year without the consent of the other parties and Summit.

If Summit proposes to register any of its equity securities under the Securities Act either for Summit’s own account or any of its stockholders (other than pursuant to registrations on Form S-4 or any successor form, on Form S-8 or any successor form relating solely to securities issued pursuant to any benefit plan, an offering of securities solely to then-existing stockholders of Summit, a dividend reinvestment plan, an exchange offer or a registration on any registration form which does not permit secondary sales or does not include substantially the same information as would be required to be included in a Registration Statement) (each such registration not withdrawn or abandoned prior to the effective date thereof being herein called a “Piggyback Registration”), Summit will give written notice to Investor of such proposal not later than the twentieth day prior to the anticipated filing date of such Piggyback Registration.

The foregoing description of the Registration Rights Agreement does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Registration Rights Agreement Term Sheet, a copy of which is attached as Exhibit B to the Stockholder Agreement, which is attached hereto as Exhibit A to the Transaction Agreement, and the terms of which are incorporated herein by reference.

Subject to and effective upon the consummation of the Transaction, Summit will enter into a Restrictive Covenant Agreement with Grupo Argos and Cementos Argos, pursuant to which Grupo Argos and Cementos Argos will be bound by certain non-compete restrictions until the fifth anniversary of the closing date, providing that Grupo Argos and its controlled affiliates and Cementos Argos and its affiliates may not own any interest, operate, manage, join, control or acquire any business that competes with the Restricted Business within British Columbia, Canada and within certain states in the United States, set forth on an exhibit to the Restrictive Covenant Agreement, and which such exhibit reflects the combined footprint in Canada and the United States of Summit and Argos USA’s activities relating to the Restricted Business as of the date of the Transaction Agreement.

Additionally, pursuant to the Restrictive Covenant Agreement, for a period beginning upon the consummation of the Transaction and continuing until the fifth anniversary of the closing date, Grupo Argos (and its controlled affiliates) and Cementos Argos (and its affiliates) will grant a right of first offer to Summit for any Potential Cementitious Opportunity, Potential RMC Opportunity and any Potential Aggregates Opportunity (in each case, as defined in the Restrictive Covenant Agreement).

Pursuant to the Restrictive Covenant Agreement, for a period beginning upon the consummation of the Transaction and continuing until the second anniversary of the closing date, Grupo Argos, Cementos Argos and Summit, and their respective affiliates, will be bound by customary non-solicit and no-hire provisions, pursuant to which the parties may not solicit for employment or hire certain specified service providers of the other party, subject to certain customary exceptions.

Subject to and effective upon the consummation of the Transaction, Summit will enter into a Transition Services Agreement with Cementos Argos, pursuant to which Cementos Argos will provide certain transition services to Argos USA and its subsidiaries in order to effect the orderly transfer of Argos USA from Cementos

Argos to Summit, including with respect to certain finance, business development, software development, environmental sustainability and supply chain functions. The term of the Transition Services Agreement will be from the closing date until the earlier of (i) the date that is the last day prior to the month that includes the day falling six months after the closing date and (ii) the earlier termination of all services provided thereunder in accordance with the terms thereof, subject to up to three potential six-month extensions for services for which a transition has not been completed by such time. In consideration for the provision of each service, Summit will pay to Cementos Argos a monthly fee on a service-by-service basis, as well as reimburse Cementos Argos for other reasonable and necessary out-of-pocket costs incurred by Cementos Argos with respect to third parties in connection with the provision of such services.

Subject to and effective upon the consummation of the Transaction, Summit will enter into a Support Services Agreement with Summa, pursuant to which Summa will provide certain services to Argos USA, including with respect to certain finance, human resources, software development, cybersecurity and information technology functions. The term of the Support Services Agreement will be from the closing date until the earlier of (i) the last end date specified for each service and (ii) the earlier termination of all services provided thereunder in accordance with the terms thereof, subject to up to four potential six-month or three-month extensions for certain services at the request of Summit. In consideration for the provision of each service, Summit will pay to Summa a monthly fee on a service-by-service basis, as well as reimburse Summa for other reasonable and necessary out-of-pocket costs incurred by Summa with respect to third parties in connection with the provision of such services.

Subject to and effective upon the consummation of the Transaction, Argos USA will enter into a Cement Supply Agreement with Zona Franca, an affiliate of Cementos Argos that owns the Cartagena Plant, with an initial term lasting until December 31, 2028, subject to extension by mutual agreement of the parties. Pursuant to the Cement Supply Agreement, Argos USA will purchase a specified minimum volume of cement during each full calendar year during the initial term, subject to Argos USA’s right to reduce such amount by up to 15%. From the closing date through December 31^st of the calendar year in which the closing date falls, Argos USA will purchase an amount of cement based on the amount of cement agreed between Zona Franca and Argos USA for such calendar year under a pre-existing supply arrangement between Zona Franca and Argos USA (which arrangement will be terminated as of the closing date). Argos USA’s purchases under the Cement Supply Agreement will be at import parity prices determined annually based on third-party quotes and will be delivered to Argos USA pursuant to the Logistics Service Agreement (Cartagena), as described below. The Cement Supply Agreement obligates Zona Franca to supply cement from the Cartagena Plant or from an alternate source in certain events of unavailability. Whether or not Argos USA takes delivery of, or Zona Franca delivers, the minimum volume for each year, each of Argos USA and Zona Franca will pay, as applicable, for an annual tonnage of cement as further specified in the Cement Supply Agreement.

Subject to and effective upon the consummation of the Transaction, Summit and Argos USA will enter into an Intellectual Property License Agreement with Cementos Argos, pursuant to which the parties will grant each other various intellectual property licenses. For purposes of the Intellectual Property License Agreement, the following terms will have the following meanings:

Pursuant to the Intellectual Property License Agreement, Cementos Argos will grant to Summit perpetual, royalty-free licenses under certain intellectual property rights owned or licensable by Cementos Argos or any of

its subsidiaries as of the closing date that, as applicable, would otherwise be infringed by, or that are practiced, used or embodied by, (i) the conduct of the Business as conducted as of the closing date, or (ii) the products and services sold or otherwise commercially provided by Argos USA and its subsidiaries as of the closing date in the conduct of the Business, to make, sell and otherwise commercially exploit products and services in the Licensed Field in the United States and Canada. Such licenses will be exclusive (including with respect to Cementos Argos and its subsidiaries) until the fifth anniversary of the closing date, or, if sooner, until certain change of control events occur with respect to either Summit or Argos USA, and non-exclusive thereafter.

Cementos Argos will also grant to Summit a perpetual, royalty-bearing license under certain calcined clay-related intellectual property rights to make, sell and otherwise commercially exploit products and services in the Licensed Field in the United States and Canada (such license, the “Calcined Clay IP License”). The Calcined Clay IP License will be exclusive (even as to Cementos Argos and its subsidiaries) until the seventh anniversary of the closing date, or, if sooner, until certain change of control events occur with respect to either Summit or Argos USA. Prior to the closing date, the parties will negotiate in good faith the terms and conditions of a potential option for Summit to extend the exclusivity period of the Calcined Clay IP License for an additional five years. If the parties are unable to reach an agreement regarding the terms and conditions of such option, the exclusivity period of the Calcined Clay IP License will automatically terminate per the terms summarized above, and the Calcined Clay IP License will be non-exclusive thereafter. During and after the exclusivity period, Summit will be required to pay a royalty to Cementos Argos in an amount to be negotiated by the parties in good faith prior to the closing date or otherwise an agreed default royalty. Cementos Argos will also grant to Summit a non-exclusive, perpetual, royalty-free license under certain microalgae-related intellectual property rights, solely for use at a certain Argos USA cement plant and solely in the Licensed Field, of certain technology developed by Cementos Argos at such plant.

For a period of five years following the closing date, Cementos Argos will also grant to Summit an exclusive (even as to Cementos Argos and its subsidiaries), royalty-free license to use and display the ARGOS name and other related trademarks (i) in legal identifiers of Summit or any of its subsidiaries and (ii) in the Licensed Field, in each case in the United States and Canada. Summit may request that the parties negotiate in good faith for a royalty-bearing extension of such license.

Lastly, Argos USA will grant to Cementos Argos a worldwide, non-exclusive, perpetual, royalty-free license under certain intellectual property rights owned or licensable by Argos USA or any of its subsidiaries as of immediately prior to the closing date that relate to the business of Cementos Argos and its affiliates as conducted as of the closing date, or that cover or claim any improvements to certain calcined clay products and technology developed by Summit or any of its subsidiaries after the closing date but prior to the occurrence of certain change of control events with respect to Summit or Argos USA, to make, sell and otherwise commercially exploit any and all products and services.

Subject to and effective upon the consummation of the Transaction, in connection with the Cement Supply Agreement, Argos USA will enter into a Logistics Service Agreement with TACC, pursuant to which Argos USA will delegate to TACC the hiring of a pneumatic vessel and open hatch/conventional vessels to transport the cement purchased from Zona Franca under the Cement Supply Agreement to terminals designated by Argos USA in the United States. TACC’s chartering services (other than with respect to pneumatic port terminals, for which Argos USA will assume the actual costs of delivery on a pass-through basis) will be subject to an address commission payable by Argos USA to TACC.

Subject to and effective upon the consummation of the Transaction, Argos USA will enter into a Master Purchase Agreement with BVI, pursuant to which Argos USA will hire BVI to, on its behalf and at its request, negotiate and coordinate supply agreements with international suppliers for the purchase of cement, cementitious materials, clinker or other raw materials and ancillary equipment to be imported into the United States and Canada. The initial term of the Master Purchase Agreement will run from the closing date until December 31, 2025, at which point the agreement will automatically renew for subsequent one-year terms unless notice of non-renewal is provided by either party. Argos USA will agree that, during the initial term, BVI will be the exclusive agent of Argos USA and its affiliates with respect to the negotiation of supply agreements with

international suppliers for the purchase of cement, cementitious materials, clinker and other raw materials and ancillary equipment to be imported into the United States and Canada. Products purchased under the Master Purchase Agreement will be subject to an address commission payable by Argos USA to BVI.

Subject to and effective upon the consummation of the Transaction, Argos USA will enter into an International Logistics Service Agreement with TACC, pursuant to which Argos USA will hire TACC to, on its behalf and at its request, negotiate and coordinate international maritime transportation, including of cement, cementitious materials, clinker or other raw materials and ancillary equipment purchased by Argos USA under the Master Purchase Agreement. The initial term of the International Logistics Service Agreement will run from the Closing Date until December 31, 2025, at which point the agreement will automatically renew for subsequent one-year terms unless notice of non-renewal is provided by either party. Argos USA will agree that, during the initial term, TACC will be the exclusive logistics service provider of Argos USA and its affiliates in the United States and Canada with respect to international maritime transportation of cement, cementitious materials, clinker and other raw materials and ancillary equipment. Products shipped under the International Logistics Service Agreement will be subject to an address commission payable by Argos USA to TACC.

As part of the ongoing evaluation of the strategic direction of Summit, the Board and management of Summit regularly evaluate Summit’s historical performance, competitive position, future growth prospects and overall strategic positioning in light of the then-current business and economic environments, as well as developments in the industries in which Summit operates, and the opportunities and challenges facing participants in its industry. These ongoing reviews have included consideration of, and discussions with other companies from time to time regarding, industry developments and potential strategic alternatives, including business combinations and other strategic transactions. In connection with these ongoing reviews, Summit has relied on a team of legal, financial and other advisors with an extensive understanding of Summit’s business, including Morgan Stanley.

Between 2018 and mid-2019, members of the management teams of Summit and Cementos Argos held several preliminary conversations regarding a potential business combination between the two companies, but these conversations were abandoned when news of a potential business combination between the two companies was leaked to the market.

On April 19, 2021, following discussion with the Board, Anne Noonan, the president and chief executive officer of Summit, Brian Harris, the executive vice president and chief financial officer of Summit, at the time, Chris Gaskill, the executive vice president, chief legal officer and secretary of Summit, Trent Musso, the senior vice president, head of business development of Summit, Alejandro Piedrahita, the chief financial officer of Grupo Argos, Juan Camilo Martínez Pérez, then the director of strategy and M&A of Grupo Argos and now the strategic projects manager of Cementos Argos, and Felipe Aristizábal, then the strategy and M&A head of Grupo Argos and now the chief financial officer of Cementos Argos, held a call to informally explore a potential business combination of Summit and Argos USA.

On April 22, 2021, Summit and Grupo Argos entered into a mutual confidentiality agreement with a two year term, which included a customary two year reciprocal standstill provision (with customary fall-away provisions) (the “Confidentiality Agreement”).

Between April 2021 and July 2021, Summit continued to have discussions with Grupo Argos and Cementos Argos regarding a potential transaction. During this period, the Board continued to meet with members of Summit management and its legal and financial advisors to review the ongoing discussions with Grupo Argos and Cementos Argos. Members of Summit management also held regular meetings with representatives of Morgan Stanley to discuss a potential transaction.

Over the course of the following six months, Summit focused on internal opportunities, as well as other strategic opportunities, and did not hold any discussions with Grupo Argos and Cementos Argos with respect to a potential transaction. During this period, Summit continued to meet with Morgan Stanley to discuss strategic opportunities, including a potential business combination of Summit and Argos USA.

On February 15, 2022, Ms. Noonan and Mr. Harris attended meetings in Colombia with members of Grupo Argos. At the meeting, the parties held general business discussions and continued to explore whether there was a potential strategic fit between their two organizations.

On April 8, 2022, members of management of Summit, Grupo Argos and Cementos Argos and representatives of Morgan Stanley and J.P. Morgan Securities LLC, the financial advisor to Cementos Argos (“JP Morgan”), held a meeting. At the meeting, Summit shared its preliminary valuation metrics for a potential business combination, which proposed that the aggregate consideration to be paid by Summit in a potential transaction would consist of (i) approximately $1.25 billion in cash consideration (subject to working capital and net indebtedness adjustments) and (ii) stock consideration representing a pro forma ownership of Summit in the range of 28-32%.

Over the course of the following six months, Summit continued to evaluate a potential business combination with Argos USA to ensure that the proposed transaction fit within Summit’s broader company strategy.

During the month of October 2022, Ms. Noonan and Jorge Mario Velásquez, the Chief Executive Officer of Grupo Argos, held several discussions to further explore a potential combination of Summit and Argos USA. During this period, representatives of Morgan Stanley and JP Morgan, also held discussions regarding a potential transaction.

On December 2, 2022, Summit, Grupo Argos and Cementos Argos amended the Confidentiality Agreement to (i) add Cementos Argos as a party thereto, including for purposes of the reciprocal standstill and non-solicit, and (ii) extend the term of the agreement, the standstill and non-solicit to December 6, 2024.

On January 17, 2023, the Board held a meeting, which was attended by members of Summit management and representatives of Morgan Stanley. At the meeting, the representatives of Morgan Stanley provided an update to the Board on the recent meetings and conversations held with Grupo Argos and Cementos Argos. Following discussion, the Board authorized Summit management to continue to explore a potential business combination of Summit and Argos USA.

On February 2, 2023, members of management of Summit, Grupo Argos, Cementos Argos and Argos USA and representatives of Morgan Stanley and J.P. Morgan participated in reciprocal management presentations relating to a potential business combination of Summit and Argos USA.

On February 14, 2023, Ms. Noonan and Mr. Velásquez discussed next steps in connection with a potential combination of Summit and Argos USA.

On February 23, 2023, the Board held a meeting, which was attended by members of Summit management and representatives of Morgan Stanley. At the meeting, the representatives of Morgan Stanley provided an update to the Board on the recently held reciprocal management presentations and conversations held with Grupo Argos and Cementos Argos. Following discussion, the Board agreed to continue to explore a potential business combination of Summit and Argos USA.

On March 9, 2023, Summit, Grupo Argos, Cementos Argos and Argos USA entered into a mutual clean team agreement in order to facilitate the sharing of limited, particularly sensitive, non-public, confidential and proprietary information regarding each party’s business. Shortly thereafter, Summit provided Grupo Argos, Cementos Argos and its advisors with access to a virtual data room to perform due diligence on Summit and Grupo Argos and Cementos Argos provided Summit and its advisors with access to a virtual data room to perform due diligence on Argos USA.

Between March 2023 and August 2023, Summit, Grupo Argos, Cementos Argos and their respective advisors conducted reciprocal due diligence. During this period, the parties held numerous telephonic due diligence sessions attended by employees from each company, covering a variety of financial, legal and operational matters. Over the course of due diligence, Cementos Argos provided Summit with information that was prepared in connection with a potential initial public offering of Argos USA. In addition, the parties participated in numerous reciprocal site visits during the months of June 2023 and July 2023.

On May 5, 2023, Ms. Noonan provided Mr. Velásquez with meeting materials in advance of a previously scheduled meeting, which proposed that the aggregate consideration to be paid by Summit in a potential transaction would consist of (i) approximately $1.27 billion in cash consideration (subject to working capital and net indebtedness adjustments) and (ii) an amount of Class A Common Stock that would provide Cementos Argos with an implied pro forma ownership of Summit in the range of 19-24%. Summit’s proposal was based on the

financial information that had been made available by Grupo Argos as of that date and Summit noted that, if Summit was provided with additional financial information that could be validated during its due diligence, Summit would reconsider its proposal. After reviewing the meeting materials, Grupo Argos instructed JP Morgan to share certain incremental financial information with Morgan Stanley that could be incorporated into Summit’s proposal.

On May 12, 2023, Ms. Noonan, Kekin Ghelani, the executive vice president, chief strategy and growth officer of Summit, Mr. Velásquez and Juan Esteban Calle, the Chief Executive Officer of Cementos Argos, attended a meeting in New York, New York to discuss the terms and conditions of a potential transaction between the parties. Also in attendance were representatives of Morgan Stanley and JP Morgan. At the meeting, Summit proposed that the aggregate consideration to be paid by Summit in a potential transaction would consist of (i) approximately $1.22 billion in cash consideration (subject to working capital and net indebtedness adjustments) and (ii) an amount of Class A Common Stock that would provide Cementos Argos with an implied pro forma ownership of Summit in the range of 23-28%. In addition, with respect to governance arrangements, Summit proposed that Cementos Argos (i) would have the right to appoint 1 or 2 directors to the Board and (ii) would be subject to a customary lock-up, standstill and voting agreement in respect of the stock consideration received in the transaction. Cementos Argos pushed back on the right to appoint only 1 or 2 directors to the Board. Following discussion, the parties agreed to a tentative pre-diligence pro forma ownership target range of 30-32%, subject to agreeing on various other matters, including governance. On the basis of this tentative agreement, the parties agreed to advance reciprocal confirmatory due diligence to validate assumptions regarding potential synergies and operational and financial performance in order to determine if mutually agreeable transaction terms could be developed.

On May 19, 2023, Ms. Noonan and Mr. Velásquez exchanged correspondence regarding the current status of the potential transaction and a mutual commitment to explore it further.

On May 25, 2023, the Board held a meeting, which was attended by members of Summit management and representatives of Morgan Stanley. At the meeting, the representatives of Morgan Stanley led a discussion regarding, among other things, (i) the recent meetings and conversations held with Grupo Argos and Cementos Argos, including the key terms discussed at the May 12, 2023 meeting, (ii) the proposed transaction structure and (iii) preliminary financial analyses regarding the proposed transaction.

On June 14, 2023, representatives of Davis Polk and Sullivan & Cromwell held an initial video conference meeting to discuss the proposed transaction and initial high level issues that had been shared between the parties. During the meeting, Sullivan & Cromwell raised their client’s concern with potentially becoming an investment company under Investment Company Act rules by virtue of their significant beneficial ownership stake in Summit, which would represent a substantial portion of their asset base. Sullivan & Cromwell noted that, in order to avoid becoming an investment company under the Investment Company Act, Grupo Argos and Cementos Argos would need an unspecified number of governance rights to qualify for the “primarily controlled company” exception under the Investment Company Act. Davis Polk and Sullivan & Cromwell also discussed the structure of the proposed transaction, which Sullivan & Cromwell proposed (i) would be a public company style transaction with no surviving representations, warranties, pre-closing covenants or indemnification, (ii) would include a sharing of Cementos Argos’s transaction expenses and (iii) would not include a purchase price adjustment for working capital, cash and indebtedness.

On June 26, 2023, the management and operations teams of Summit and Argos USA attended all-day due diligence meetings regarding ready-mixed concrete.

On June 27, 2023, the management and operations teams of Summit and Argos USA attended all-day due diligence meetings regarding cement.

On June 30, 2023, members of management of Summit, Grupo Argos and Cementos Argos and representatives of Morgan Stanley and JP Morgan held a meeting in Denver, Colorado. At the meeting, Summit provided its proposed governance terms for the Class A Common Stock that Cementos Argos would receive in a potential business combination.] Under Summit’s proposed governance terms, Cementos Argos would receive, among other things, (i) the right to designate [3] directors of an expanded [12] person board of directors of Summit, subject to certain fall-away provisions (including proportionate step-downs in the right to designate directors as Cementos Argos decreases its beneficial ownership in Summit), and (ii) customary registration rights. In addition, Cementos Argos would be subject to, among other things, (a) a “standstill” obligation that would

apply until six months after the date on which Cementos Argos owned less than 5% of the outstanding shares of Class A Common Stock, (b) a two-year lock-up, after which, for as long as Cementos Argos beneficially owned 5% or more of the outstanding shares of Class A Common Stock, Cementos Argos would be restricted from transferring shares of Class A Common Stock that would result in a transferee owning more than 5% of the outstanding shares of Class A Common Stock and (c) certain voting requirements for Cementos Argos to vote its shares in favor of certain Board actions. Summit’s proposed governance terms did not include any stockholder approval or consent rights.

On July 7, 2023, representatives of Morgan Stanley, as directed by Summit, delivered to representatives of JP Morgan Summit’s proposed transaction terms for the proposed business combination. Under Summit’s proposed transaction terms, Summit proposed, among other things, that (i) the purchase price for all of the outstanding equity interests of Argos USA would be a combination of a to-be-agreed-upon amount of cash and Class A Common Stock, subject to a one-way customary purchase price adjustment for Argos USA’s cash, debt and debt-like items, working capital (relative to an agreed upon target) and transaction expenses, (ii) both parties would be subject to reciprocal no-shop covenants, (iii) Cementos Argos would receive a termination fee of 2% of the purchase price of the transaction if Summit’s board of directors changed its recommendation or if Summit terminated the transaction to enter into a superior proposal, (iv) both parties would be required to use reasonable best efforts to obtain regulatory approvals, subject to certain limitations, and (v) both parties would provide customary indemnities to the other party and that the representations, warranties and pre-closing covenants of the parties would survive the closing of the Transaction.

On August 8, 2023, Cementos Argos responded to Summit’s proposed transaction terms. Cementos Argos proposed, among other things, that (i) the purchase price adjustment would be limited to cash, borrowed money debt and working capital (relative to an agreed upon target), (ii) Cementos Argos would receive a termination fee of 4% of the implied equity value of Summit and it would be payable under certain additional circumstances, (iii) Summit would reimburse Cementos Argos for all of Cementos Argos’s expenses incurred in pursuit of the transaction up to 1% of the implied equity value of Summit, (iv) the “burdensome condition” closing condition relating to regulatory matters would be mutual and defined as a material adverse effect on the combined company and (v) that there would be no indemnification for representations, warranties, pre-closing covenants, pre-closing taxes, indebtedness or transaction expenses and the representations, warranties, pre-closing covenants would not survive the closing of the transaction.

On August 10, 2023, representatives of Summit, Cementos Argos and each of their respective legal and financial advisors held a video conference call to discuss the proposed terms of the transaction. During the call, Summit proposed, among other things, that the Cementos Argos termination fee be decreased to 3% of the purchase price of the transaction. Summit also rejected Cementos Argos’s proposal for expense reimbursement and a no indemnity transaction.

On August 12, 2023, Sullivan & Cromwell delivered to Davis Polk an initial draft of the Stockholder Agreement proposed to be entered into with respect to the proposed transaction. Under the proposed draft of the Stockholder Agreement, the parties would agree, among other things, that (i) Cementos Argos would have the right to designate 4 directors, with proportionate step-downs in such right between 25% and 5% of Cementos Argos’s beneficial ownership of Class A Common Stock, (ii) at least one Cementos Argos director would serve on each committee of the board so long as Cementos Argos and its affiliates beneficially own greater than 12.5% of the outstanding Class A Common Stock, (iii) so long as Cementos Argos and its affiliates beneficially own greater than 25% of the outstanding Class A Common Stock, Summit and its subsidiaries would not (a) incur indebtedness over a specified leverage ratio, (b) enter into any material agreements or arrangements with affiliates of Summit or its subsidiaries in excess of an unspecified amount, (c) fundamentally change the business or material investments of Summit to an extent that would constitute a significant departure from Summit’s existing business or (d) voluntarily liquidate, dissolve or wind-up Summit or any of its material subsidiaries, (iv) so long as Cementos Argos and its affiliates beneficially own greater than 12.5% of the outstanding Class A Common Stock (and for any 12 month period after they fall below such threshold), Cementos Argos would have the right to purchase up to its pro rata portion of any equity securities that Summit may from time to time propose to issue or sell to any person, including in circumstances where Summit issues equity to the sellers in an unrelated, ordinary course M&A transaction and (v) so long as Cementos Argos and its affiliates beneficially own greater than 25% of the outstanding Class A Common Stock, Cementos Argos would provide managerial support to Summit with respect to manufacturing, financial, marketing and other areas as needed and requested

by management of Summit, in each case, on commercially reasonable terms and conditions to be agreed in writing by Cementos Argos and Summit. The draft of the Stockholder Agreement also proposed a narrower standstill obligation than the standstill initially proposed by Summit, including a number of fall-away events under which the standstill would no longer be in force or effect.

On August 15, 2023, the Board held a meeting, which was attended by members of Summit management and representatives of Davis Polk and Morgan Stanley. At the meeting, the members of Summit management led a discussion regarding the status of the due diligence process run by management. The representatives of Morgan Stanley then led a discussion regarding Morgan Stanley’s preliminary financial analyses. Following discussion, the representatives of Davis Polk then led a discussion regarding the legal and regulatory considerations in connection with the proposed transaction with Argos USA and the Summit directors’ fiduciary duties, including in connection with the proposed transaction.

Between August 16, 2023 and August 18, 2023, members of management of Summit and Cementos Argos met to negotiate the terms and conditions of the commercial agreements proposed to be entered into with respect to the proposed transaction.

Between August 22, 2023 and August 25, 2023, members of management of Summit, Cementos Argos and Grupo Argos met to finalize governance and financial terms. At the conclusion of these meetings, the parties agreed that the aggregate consideration to paid in the transaction would consist of (i) $1.2 billion in cash consideration (subject to working capital and net indebtedness adjustments) and (ii) 54,720,000 Class A Common Stock.

On August 31, 2023, Davis Polk delivered to Sullivan & Cromwell an initial draft of the Transaction Agreement.

Between August 31, 2023 and the execution of the Transaction Agreement on September 7, 2023, representatives of Summit, Grupo Argos, Cementos Argos, Davis Polk and Sullivan & Cromwell held multiple meetings to negotiate the terms of the Transaction Agreement and ancillary documents.

On September 5, 2023, the Board held a meeting, which was attended by representatives of Davis Polk and Morgan Stanley. At the meeting, Davis Polk led a discussion with the Board regarding the fiduciary duties of the Board members in connection with the proposed transaction. Davis Polk then provided the Board with a summary of the key terms and conditions of the Transaction Agreement and the Stockholder Agreement. Mr. Gaskill then provided the Board with an update on the negotiations of the key terms and conditions of the other commercial and transaction agreements to be entered into in connection with the proposed transaction. Morgan Stanley then reviewed with the Board its financial analyses with respect to the proposed transactions. Representatives of Morgan Stanley rendered to the Board an oral opinion, which was subsequently confirmed by delivery of a written opinion dated September 5, 2023, that, as of such date, based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Morgan Stanley as set forth in its written opinion, the Consideration to be paid by Summit pursuant to the Transaction Agreement was fair from a financial point of view to Summit. For a detailed discussion of Morgan Stanley’s opinion, please see “The Transaction — Opinion of Summit’s Financial Advisor.” After discussion, the Board unanimously (i) determined that the terms of the Transaction Agreement and the transactions contemplated by the Transaction Agreement and the other Transaction Documents were fair to and in the best interests of Summit and the Summit Stockholders, (ii) approved and declared advisable the Transaction Agreement and the transactions contemplated by the Transaction Agreement and the other Transaction Documents, (iii) directed that the issuance of Summit Common Stock and Summit Preferred Stock comprising the Stock Consideration be submitted to the Summit Stockholders for approval (the “Proposals”), and (iv) resolved, subject to the no solicitation provision of the Transaction Agreement, to recommend that the Summit Stockholders vote in favor of the Proposals.

On September 7, 2023, before the markets opened, Summit announced that it had entered into the Transaction Agreement.

On October 6, 2023, the Board received an indicative, non-binding proposal from a representative of Company A (the “Company A Proposal Letter”) to acquire 100% of the fully diluted equity interests in Summit for $37.50 per share of Class A Common Stock payable in cash. On October 11, 2023, Summit received a draft agreement and plan of merger from Company A (together with the Company A Proposal Letter, the “Company A Proposal”).

On October 12, 2023, the Board held a meeting, which was attended by members of Summit management and representatives of Davis Polk and Morgan Stanley. At the meeting, the Board carefully reviewed and

considered the Company A Proposal with its advisors. Following such review and consideration, the Board was not able to determine that the Company A Proposal would reasonably be likely to constitute or lead to a Superior Proposal and, as a result, the Company was unable to engage with Company A at that time on the Company A Proposal (the restrictions on the Company’s ability to discuss alternative transactions with third parties are described in the section titled “No Solicitations by the Company” beginning on page 25 of this proxy statement).

On October 14, 2023, the Chairman of the Board notified Company A of the Board’s determination with respect to the Company A Proposal.

On October 18, 2023, the Board received a revised proposal from a representative of Company A to acquire 100% of the fully diluted equity interests in Summit for $38.00 per share of Class A Common Stock payable in cash (the “Revised Company A Proposal”). Later that same day, the Board held a meeting, which was attended by members of Summit management and representatives of Davis Polk and Morgan Stanley. At the meeting, the Board carefully reviewed and considered the Revised Company A Proposal with its advisors. Following such review and consideration, the Board was not able to determine that the Revised Company A Proposal would reasonably be likely to constitute or lead to a Superior Proposal and, as a result, the Company is unable to engage with Company A at this time on the Revised Company A Proposal (the restrictions on the Company’s ability to discuss alternative transactions with third parties are described in the section titled “No Solicitations by the Company” beginning on page 25 of this proxy statement).

Also on October 18, 2023, the Chairman of the Board notified Company A of the Board’s determination with respect to the Revised Company A Proposal.

On September 5, 2023, the Board unanimously (i) determined that the terms of the Transaction Agreement and the transactions contemplated by the Transaction Agreement and the other Transaction Documents were fair to and in the best interests of Summit and the Summit Stockholders, (ii) approved and declared advisable the Transaction Agreement and the transactions contemplated by the Transaction Agreement and the other Transaction Documents, (iii) directed that the issuance of Summit Common Stock and Summit Preferred Stock comprising the Stock Consideration be submitted to the Summit Stockholders for approval, and (iv) resolved, subject to the no solicitation provision of the Transaction Agreement, to recommend that the Summit Stockholders vote in favor of the Proposals.

Accordingly, the Board recommends that you vote “FOR” the Common Stock Issuance Proposal, “FOR” the Preferred Stock Issuance Proposal and “FOR” the Adjournment Proposal.

In reaching its recommendation, the Board consulted with and received the advice of its independent financial and legal advisors and discussed certain matters with Summit’s management team. The following are some of the significant factors that supported the Board’s recommendation that the Board approve the Transaction Agreement and the transactions contemplated thereby (which are not necessarily presented in order of relative importance):

The Board, in consultation with its legal, financial and other advisors, also considered the following specific aspects of the Transaction Agreement and the Transaction Documents (which are not necessarily presented in order of relative importance):

In the course of its deliberations, the Board also considered a variety of risks, uncertainties and other potentially negative factors, including the following (which are not necessarily presented in order of relative importance):

The Board considered all of these factors as a whole and concluded that the uncertainties, risks and potentially negative factors relevant to the transactions were outweighed by the potential benefits that it expected Summit Stockholders would achieve as a result of the Transaction. The foregoing discussion of the information and factors considered by the Board is not exhaustive. In view of the wide variety of factors considered by the Board in connection with its evaluation of the Transaction and the complexity of these matters, the Board did not consider it practical to, nor did it attempt to, quantify, rank or otherwise assign relative weights to the specific factors that it considered in reaching its decision. In considering the factors described above and any other factors, the individual members of the Board may have viewed factors differently or given different weight or merit to different factors.

The foregoing discussion of the information and factors considered by the Board is forward-looking in nature. This information should be read in light of the factors described in the section entitled “Cautionary Statement Concerning Forward-Looking Information.”

Summit does not, as a matter of course, make public long-term projections as to future revenues, earnings or other results due to, among other reasons, the uncertainty, unpredictability and subjectivity of the underlying assumptions and estimates. However, in connection with the evaluation of the Transaction, the management of Summit prepared certain non-public financial projections (i) for Summit on a standalone basis for the calendar years 2023 through 2028 (the “Summit financial projections”) and (ii) for Argos USA and its subsidiaries for the

calendar years 2023 through 2028 (the “Argos USA financial projections” and together with the Summit financial projections, the “financial projections”), which were provided to the Summit board of directors for its evaluation of the Transaction and to Morgan Stanley, Summit’s financial advisor, for its use in advising Summit and reliance in connection with its preparation of its financial analyses and opinion as described in the section entitled “—Opinion of Financial Advisor to Summit.”

A summary of the financial projections is not being included in this proxy statement to influence your decision whether to vote for or against the Common Stock Issuance Proposal or the Preferred Stock Issuance Proposal, but is being included because such financial projections were made available to the Summit board of directors and Summit’s financial advisor. The inclusion of this information should not be regarded as an indication that the Summit board of directors, Summit (or any of its affiliates, officers, directors, advisors or other representatives), Morgan Stanley or any other person considered, or now considers, the financial projections to be necessarily predictive of actual future events or results of Summit’s or Argos USA’s respective operations and should not be relied upon as such. The assumptions used by the management of Summit in developing the Summit financial projections and the Argos USA financial projections, are subjective in many respects. There can be no assurance that the projections contained in the financial projections will be realized or that actual results will not vary materially than those forecasted. The financial projections cover multiple years and such information by its nature becomes less predictive with each successive year. As a result, the financial projections summarized in this proxy statement should not be relied on as necessarily predictive of actual future events.

In addition, neither the Summit financial projections nor the Argos USA financial projections were prepared with a view to publicly disclosing such information or to complying with GAAP, published guidelines of the SEC or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of forecasted financial information. Neither Summit’s independent registered public accounting firm, nor any other independent accountants, have audited, compiled, examined or performed any procedures with respect to the financial projections summarized in this proxy statement, nor have they expressed any opinion or provided any other form of assurance with respect to such information or the achievability of the projections contained therein.

The management of Summit developed the Summit financial projections and the Argos USA financial projections utilizing reasonably available estimates and judgments at the time of its preparation. The Summit financial projections and the Argos USA financial projections are based on numerous variables and assumptions that were deemed to be reasonable as of the date on which such projections were finalized. However, such assumptions are inherently uncertain and difficult or impossible to predict or estimate and most of them are beyond Summit’s control. The material assumptions made by the management of Summit in developing the internal financial forecasts upon which the Summit financial projections and Argos USA financial projections are based, respectively, include, without limitation: (i) no unannounced acquisitions, (ii) non-adverse weather-related conditions with unusual intensity and/or during abnormal periods in the forward-looking periods, (iii) ongoing investments in Summit’s and Argos USA’s existing entities for maintenance, integrity and other capital expenditures and (iv) no material fluctuations in interest rate assumptions over the forward-looking periods. The financial projections also reflect assumptions regarding the continuing nature of certain business decisions that, in reality, are subject to change. The Argos USA financial projections and the Summit financial projections are generally based on information known to Summit management as of August 2023.

Important factors that may affect actual results and cause the projections contained in the financial projections not to be achieved include, but are not limited to: (i) risks and uncertainties relating to Summit’s and Argos USA’s businesses (including the ability to achieve strategic and financial objectives and risks associated with Summit’s and Argos USA’s existing and future technologies, intellectual property, products, services and business models), (ii) the timing and risks associated with the integration of Argos USA and Summit, (iii) the retention of key employees of Argos USA and Summit, (iv) industry performance, (v) the legal and regulatory environment, (vi) general business and economic conditions and (vii) other factors described in this proxy statement or described or referenced in Summit’s filings with the SEC, including the Annual Report, subsequent quarterly reports on Form 10-Q and current reports on Form 8-K. The financial projections summarized in this proxy statement constitute “forward-looking statements” and actual results may differ materially and adversely from those projected. For more information, please see the section entitled “Cautionary Statement Regarding Forward-Looking Statements.” In addition, the summaries of the financial projections reflect assumptions that are

subject to change and do not reflect revised prospects for Summit’s or Argos USA’s respective businesses, changes in general business or economic conditions or any other transaction or event that has occurred or that may occur and that was not anticipated at the time the financial projections were prepared.

Neither Summit nor Argos USA, or any of their respective affiliates, officers, directors, advisors or other representatives, can give any assurance that actual results will not differ from the Summit financial projections or the Argos USA financial projections, nor does any such party undertake any obligation to update or otherwise revise or reconcile the financial projections to reflect circumstances existing, or developments or events occurring, after the date on which the financial projections were finalized, or that may occur in the future, even if any or all of the assumptions underlying the financial projections turn out to be incorrect. Summit does not intend to make available publicly any update or other revision to the financial projections, except as otherwise required by applicable law. None of Summit or any of its affiliates, officers, directors, advisors or other representatives has made or makes any representation to any Summit stockholder or any other person regarding the ultimate performance of Summit or Argos USA compared to the information contained in the financial projections, or that the projections contained in the financial projections will be achieved.

In light of the foregoing factors as well as the uncertainties inherent in the financial projections, and given that the Special Meeting will be held several months after the financial projections were prepared, Summit stockholders are cautioned not to place undue, if any, reliance on the information presented in this summary of the financial projections, and Summit urges all Summit stockholders to review Summit’s most recent SEC filings for a description of Summit’s reported financial results. The inclusion of this information in this proxy statement does not constitute an admission or representation by Summit or its advisors or representatives or any other person that the information is material, particularly in light of the inherent risks and uncertainties associated with such forecasts.

The Summit financial projections are made on a stand-alone basis, assuming Summit would continue as an independent company, and do not give effect to the Transaction or any changes to Summit’s operations or strategy that may be implemented after the consummation of the Transaction, including potential synergies to be realized as a result of the Transaction, or to any costs incurred in connection with the Transaction. Furthermore, the Summit financial projections do not take into account the effect of any failure of the Transaction to be completed and should not be viewed as accurate or continuing in that context.

The following table presents a summary of the Summit financial projections:

The following table presents a summary of the Summit unlevered free cash flow projections:

The Argos USA financial projections include two different sets of projections – referred to as the “Argos Base Case” and the “Synergized Case.” The Argos Base Case, representing Summit’s view (informed by Argos USA’s management) of the status quo case for Argos USA’s business without any improvements beyond Argos USA’s committed capital expenditures, is made on a stand-alone basis, assuming Argos USA would continue as an independent company, and does not give effect to the Transaction or any changes to Argos USA’s operations or strategy that may be implemented after the consummation of the Transaction, including potential synergies to be realized as a result of the Transaction, or to any costs incurred in connection with the Transaction. The Synergized Case projections are based on the Argos Base Case, plus adjustments reflecting the impact to each of calendar years 2024-2028 of operational excellence and cost combination benefits (i.e. synergies) net, of cost to achieve and incremental capital expenditures. The Argos USA financial projections do not take into account the effect of any failure of the Transaction to be completed and should not be viewed as accurate or continuing in that context.

The following tables present a summary of the Argos USA financial projections:

The following tables present a summary of the Argos USA unlevered free cash flow projections:

Adjusted EBITDA, net capital expenditures and unlevered free cash flow are non-GAAP financial measures. Non-GAAP financial measures should not be considered a substitute for, or superior to, financial measures determined or calculated in accordance with GAAP and may not be comparable with similar measures presented by other companies.

SUMMIT DOES NOT INTEND TO UPDATE OR OTHERWISE REVISE THE ABOVE FINANCIAL PROJECTIONS TO REFLECT CIRCUMSTANCES EXISTING AFTER THE DATE ON WHICH SUCH

FINANCIAL PROJECTIONS WERE FINALIZED OR TO REFLECT THE OCCURRENCE OF FUTURE EVENTS, EVEN IF ANY OR ALL OF THE ASSUMPTIONS UNDERLYING SUCH UNAUDITED FINANCIAL AND OPERATING FORECASTS ARE NO LONGER APPROPRIATE, EXCEPT AS MAY BE REQUIRED BY APPLICABLE LAW.

Morgan Stanley was retained by Summit to act as its financial advisor and to render a fairness opinion in connection with the proposed Transaction. Summit selected Morgan Stanley to act as its financial advisor based on Morgan Stanley’s qualifications, expertise and reputation, its knowledge of and experience in recent transactions in Summit’s industry and its knowledge of Summit’s business and affairs. On September 5, 2023, Morgan Stanley rendered its oral opinion, which was subsequently confirmed in writing, to the Board to the effect that, as of such date and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Morgan Stanley as set forth in its written opinion, the Consideration to be paid by Summit pursuant to the Transaction Agreement was fair from a financial point of view to Summit.

The full text of Morgan Stanley’s written opinion to the Board, dated September 5, 2023, is attached to this proxy statement as Annex K and is incorporated by reference into this proxy statement in its entirety. Summit stockholders should read the opinion in its entirety for a discussion of the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of review undertaken by Morgan Stanley in rendering its opinion. This summary is qualified in its entirety by reference to the full text of such opinion. Morgan Stanley’s opinion was directed to the Board and addressed only the fairness from a financial point of view to Summit, as of the date of the opinion, of the Consideration to be paid by Summit pursuant to the Transaction Agreement. Morgan Stanley’s opinion did not address any other aspects of the proposed Transaction and did not and does not constitute a recommendation as to how the stockholders of Summit should vote at the stockholders’ meeting to be held in connection with the proposed Transaction.

In arriving at its opinion, Morgan Stanley:

In arriving at its opinion, Morgan Stanley assumed and relied upon, without independent verification, the accuracy and completeness of the information that was publicly available or supplied or otherwise made available to Morgan Stanley by Summit, and formed a substantial basis for its opinion. With respect to the financial projections provided by the managements of Argos USA and Summit, including information relating to certain strategic, financial and operational benefits anticipated from the proposed Transaction, Morgan Stanley assumed that they were reasonably prepared on bases reflecting the best currently available estimates and judgments of the respective managements of Argos USA and Summit. Morgan Stanley relied upon, without independent verification, the assessment by the management of Summit of: (i) the strategic, financial and other benefits expected to result from the proposed Transaction; (ii) the timing and risks associated with the integration of Argos USA and Summit; (iii) their ability to retain key employees of Argos USA and Summit, respectively and (iv) the validity of, and risks associated with, Argos USA and Summit’s existing and future technologies, intellectual property, products, services and business models. In addition, Morgan Stanley assumed that the proposed Transaction will be consummated in accordance with the terms set forth in the Transaction Agreement without any waiver, amendment or delay of any terms or conditions, including, among other things, that Summit will obtain financing in accordance with the terms set forth in the Debt Commitment Letter, and that the definitive Transaction Agreement would not differ in any material respect from the draft thereof furnished to Morgan Stanley. Morgan Stanley assumed that in connection with the receipt of all the necessary governmental, regulatory or other approvals and consents required for the proposed Transaction, no delays, limitations, conditions or restrictions will be imposed that would have a material adverse effect on the contemplated benefits expected to be derived in the proposed Transaction. Morgan Stanley is not a legal, tax or regulatory advisor. Morgan Stanley is a financial advisor only and relied upon, without independent verification, the assessment of Summit and Argos USA and their legal, tax or regulatory advisors with respect to legal, tax or regulatory matters. Morgan Stanley expressed no opinion with respect to the fairness of the amount or nature of the compensation to any of the Argos USA’s officers, directors or employees, or any class of such persons, relative to the consideration to be paid to Cementos Argos or received by the holders of shares of Argos USA common stock in the proposed Transaction. Morgan Stanley did not make any independent valuation or appraisal of the assets or liabilities of Argos USA or Summit, nor was Morgan Stanley furnished with any such valuations or appraisals. Morgan Stanley’s opinion did not address the relative merits of the transactions contemplated by the Transaction Agreement as compared to other business or financial strategies that might be available to Summit, nor did it address the underlying business decision of Summit to enter into the Transaction Agreement or proceed with any other transaction contemplated by the Transaction Agreement. Morgan Stanley did not express any view on, and Morgan Stanley’s opinion did not address, any other term or aspect of the Transaction Agreement or the transactions contemplated thereby or any term or aspect of any other agreement or instrument contemplated by the Transaction Agreement or entered into or amended in connection therewith. Morgan Stanley’s opinion was necessarily based on financial, economic, market and other conditions as in effect on, and the information made available to Morgan Stanley as of September 5, 2023. Events occurring after such date may affect Morgan Stanley’s opinion and the assumptions used in preparing it, and Morgan Stanley did not assume any obligation to update, revise or reaffirm its opinion.

The following is a summary of the material financial analyses performed by Morgan Stanley in connection with the preparation of its oral opinion and written opinion delivered to the Board on September 5, 2023. The following summary is not a complete description of Morgan Stanley’s opinion or the financial analyses performed and factors considered by Morgan Stanley in connection with its opinion, nor does the order of analyses described represent the relative importance or weight given to those analyses. In connection with arriving at its opinion, Morgan Stanley considered the results of all analyses undertaken and assessed as a whole, and did not draw, in isolation, conclusions from or with regard to any one factor or method of analyses.

Considering any portion of such analyses and factors considered, without considering all analyses and factors as a whole, could create a misleading or incomplete view of the process underlying Morgan Stanley’s opinion. Some of the financial analyses summarized below include information presented in tabular format. In order to fully understand the financial analyses used by Morgan Stanley, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial analyses, and mathematical analyses (such as determining the average or median) is not in itself a meaningful method of using the data referred to below.

Unless stated otherwise, the following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before September 1, 2023, the last trading day prior to the date of the meeting of the Board at which Morgan Stanley rendered its oral opinion and is not necessarily indicative of current market conditions. Capitalization information for Summit, including fully-diluted number of shares outstanding and balance sheet information, was provided on September 1, 2023 by Summit management to Morgan Stanley, and was approved by Summit management for Morgan Stanley’s use in its financial analyses.

In performing its financial analyses summarized below and in arriving at its opinion, Morgan Stanley used and relied upon the Argos USA financial projections, the Summit financial projections and estimates of certain strategic, financial and operational benefits, including synergies, projected by the management of Summit.

For purposes of the analyses summarized below, the implied value of the Consideration to be paid by Summit was assumed to be $3.3 billion, consisting of $1.2 billion in cash consideration (assuming for such purposes that the adjustments to the cash consideration provided for in the Transaction Agreement would be equal to zero) and $2.1 billion in stock consideration, based on 54,720,000 shares of Class A Common Stock issued multiplied by the $38.37 per share closing price of Class A Common Stock on September 1, 2023.

Morgan Stanley performed a discounted cash flow, which we refer to as DCF, analysis for Argos USA, which is designed to provide an implied value of a company by calculating the present value of the estimated future cash flows and terminal value of a company.

Morgan Stanley calculated ranges of implied enterprise values for Argos USA based on the estimated cash flows contained in each of the Synergized Case (including the effect of synergies) and the Argos Base Case (which did not give effect to synergies).

For purposes of its DCF analyses, Morgan Stanley calculated a terminal value for Argos USA (based on each of the Synergized Case and the Argos Base Case) as of December 31, 2028, by applying a range of perpetual growth rates of 2.0% to 3.0%, selected based on Morgan Stanley’s experience and professional judgment, to the terminal year unlevered free cash flows and, for the Synergized Case, adjusting for the full potential run-rate synergies to be achieved after the forecast period. The unlevered free cash flows from calendar years 2024 to 2028 and the terminal value were then discounted to present values as of December 31, 2023 using a range of discount rates of 8.8% to 10.3% (which Morgan Stanley derived based on Argos USA’s assumed weighted average cost of capital using its experience and professional judgment), to calculate an implied aggregate value for Argos USA.

Based on the above-described analyses, Morgan Stanley derived an enterprise value range of Argos USA of $3.4 billion to $4.8 billion based on the Argos Base Case, and an enterprise value range of $4.2 billion to $6.0 billion based on the Synergized Case. Morgan Stanley compared these ranges to the implied value of the Consideration of $3.3 billion, consisting of $1.2 billion in cash consideration and $2.1 billion in stock consideration, based on 54,720,000 shares of Class A Common Stock issued multiplied by the $38.37 per share closing price of Class A Common Stock on September 1, 2023.

Morgan Stanley performed a comparable company trading analysis, which attempts to provide an implied value of a company by comparing it to similar companies that are publicly traded. Morgan Stanley reviewed and compared, using publicly available information, certain future financial information for Argos USA with corresponding future financial information, ratios and public market multiples for publicly traded companies in the heavy building materials space that shared certain similar business and operating characteristics to Argos USA.

These companies were chosen based on Morgan Stanley’s knowledge of the industry and because they have businesses that may be considered similar to Argos USA’s business. Although none of such companies are identical or directly comparable to Argos USA, these companies are publicly traded companies with operations and/or other criteria, such as lines of business, markets, business risks, growth prospects, maturity of business and size and scale of business, that, for purposes of its analysis, Morgan Stanley considered similar to Argos USA.

For purposes of this analysis, for each of the selected publicly traded companies listed below, Morgan Stanley analyzed the ratio of the aggregate value, which we refer to as AV, which Morgan Stanley defined as fully diluted market capitalization plus net debt, of such company to its estimated earnings before interest, taxes, depreciation and amortization, which we refer to as EBITDA, for each of calendar years 2023 and 2024. Morgan Stanley calculated the estimated enterprise value of Argos USA based on (i) the AV/EBITDA multiples for each of the selected companies for calendar year 2023, multiplied by Argos USA’s estimated EBITDA of $309 million for calendar year 2023, based on the Argos Base Case, and (ii) the AV/EBITDA multiples for each of the selected companies for calendar year 2024, multiplied by Argos USA’s estimated EBITDA of $357 million for calendar year 2024, also based on the Argos Base Case. The statistics for each of the selected companies and the corresponding estimated enterprise value of Argos USA are summarized as follows:

Morgan Stanley compared the estimated enterprise values to the implied value of the Consideration of $3.3 billion, consisting of $1.2 billion in cash consideration and $2.1 billion in stock consideration, based on 54,720,000 shares of Class A Common Stock issued multiplied by the $38.37 per share closing price of Class A Common Stock on September 1, 2023.

No company utilized in the comparable company analysis is identical to Argos USA. In evaluating comparable companies, Morgan Stanley made judgments and assumptions with regard to industry performance, general business, economic, market and financial conditions, and other matters, many of which are beyond the control of Argos USA or Summit. These include, among other things, comparable company growth, the impact of competition on the businesses of Summit and the industry generally, industry growth and the absence of any adverse material change in the financial condition and prospects of Argos USA or the industry, or in the financial markets in general. Mathematical analysis (such as determining the mean) is not in itself a meaningful method of using comparable company data.

Morgan Stanley performed a selected precedent transactions analysis, which is designed to imply a value of a company based on publicly available financial terms of selected transactions. Morgan Stanley selected certain transactions involving the acquisition of heavy building materials companies since 2015 for which relevant financial information was publicly available.

For these transactions, Morgan Stanley reviewed the consideration paid and calculated the ratio of the AV of each transaction to the EBITDA of the target company for the last twelve months, which we refer to as LTM EBITDA, based on publicly available financial information. Morgan Stanley reviewed the following transactions in connection with this analysis:

These transactions varied significantly based upon company scale, product mix, and geography. Based on its professional judgment and taking into consideration, among other things, (i) the observed multiples for the selected transactions listed above (which indicated a median AV / LTM EBITDA multiple of 11.6x), (ii) the different business, financial and operating characteristics of the companies in such transactions as compared to Argos USA and (iii) the prevailing market trends for the valuation and performance of heavy building materials companies at the time of each transaction as compared to the current prevailing market trends, Morgan Stanley selected a representative range of AV/LTM EBITDA multiples from 10.0x to 12.0x and applied this range of financial multiples to Argos USA’s LTM EBITDA as of September 30, 2023 of $295 million, based on actual results from October 1, 2022 through June 30, 2023 and forecast projections of Summit management from July 1, 2023 through September 30, 2023. Based on this analysis, Morgan Stanley derived a range of enterprise values of Argos USA of $3.0 billion to $3.5 billion. Morgan Stanley compared this range to the implied value of the Consideration of $3.3 billion, consisting of $1.2 billion in cash consideration and $2.1 billion in stock consideration, based on 54,720,000 shares of Class A Common Stock issued multiplied by the $38.37 per share closing price of Class A Common Stock on September 1, 2023.

No company or transaction utilized in the precedent transaction analysis is identical to Argos USA or the proposed Transaction. In evaluating the selected precedent transactions, Morgan Stanley made judgments and assumptions with regard to general business, market and financial conditions and other matters, that are beyond the control of Argos USA, such as the impact of competition on the business of Argos USA or the industry generally, industry growth and the absence of any adverse material change in the financial condition of Argos USA or the industry or in the financial markets in general, which could affect the public trading value of the companies and the aggregate value of the transactions to which they are being compared.

Morgan Stanley performed a DCF analysis for Summit, which is designed to provide an implied value of a company by calculating the present value of the estimated future cash flows and terminal value of a company.

Morgan Stanley calculated a range of implied equity values per share of common stock based on the estimated cash flows contained in the Summit financial projections.

For purposes of its DCF analyses, Morgan Stanley calculated a terminal value for Summit as of December 31, 2028, by applying a range of perpetual growth rates of 2.0% to 3.0%, selected based on Morgan Stanley’s experience and professional judgment, to the terminal year unlevered free cash flow. The unlevered free cash flows from calendar years 2024 to 2028 and the terminal value were then discounted to present values as of

December 31, 2023 using a range of discount rates of 8.8% to 10.3% (which Morgan Stanley derived based on Summit’s assumed weighted average cost of capital using its experience and professional judgment), and adjusted by Summit’s estimated net debt as of December 31, 2023, as provided by Summit’s management. Morgan Stanley divided the resulting equity value by the number of fully diluted shares of Summit common stock outstanding, as provided by Summit’s management, and added back between $2.54 to $2.66 per share, based on the same range of discount rates noted above, to reflect the per-share value of certain tax attributes and structuring, net of payments under Summit’s tax receivables agreement, in each case as provided by Summit’s management.

Based on the above-described analysis, Morgan Stanley derived a range of implied equity values per share of Summit common stock of $30.50 per share to $46.25 per share, rounded to the nearest $0.25 per share.

Morgan Stanley compared this equity value per share range to the closing trading price of Class A Common Stock on September 1, 2023, the last trading day prior to the date of Morgan Stanley’s presentation to the Board, of $38.37.

Morgan Stanley performed a discounted equity value analysis, which is designed to provide insight into a theoretical estimate of the future implied value of a company’s common equity as a function of such company’s estimated future earnings and a theoretical range of trading multiples. The resulting estimated future implied value is subsequently discounted back to the present day at the company’s cost of equity in order to arrive at an illustrative estimate of the present value for the company’s theoretical future implied stock price.

As part of this analysis, Morgan Stanley calculated future ranges of implied equity values per share of Summit common stock as of each of January 1, 2026, January 1, 2027 and January 1, 2028, respectively, and subsequently discounted each such theoretical future value range to arrive at an illustrative present value range of implied share prices for Class A Common Stock as of December 31, 2023.

To calculate the future ranges of implied equity values, Morgan Stanley applied a range of next twelve months, which we refer to as NTM, AV/EBITDA multiples of 8.5x to 10.5x, derived by Morgan Stanley using its experience and professional judgment, to Summit’s estimated NTM EBITDA as of each of January 1, 2026, January 1, 2027 and January 1, 2028, in each case based on the Summit financial projections, and then subtracted the amount of Summit’s estimated net debt as of each date, respectively, as provided by Summit’s management. Morgan Stanley then divided the resulting implied equity values by Summit’s fully diluted shares outstanding, as provided by Summit’s management, to derive ranges of future implied equity values per share. Morgan Stanley then discounted the resulting implied equity values per share to December 31, 2023 at a discount rate equal to 11.0%, which discount rate was selected by Morgan Stanley based upon its professional judgment and taking into account Summit’s assumed cost of equity of 11.0%.

Based on this analysis, Morgan Stanley derived a range of implied equity values per share of Class A Common Stock of $35.25 to $46.25, rounded to the nearest $0.25 per share.

Morgan Stanley compared this equity value per share range to the closing trading price of Class A Common Stock on September 1, 2023, the last trading day prior to the date of Morgan Stanley’s presentation to the Board, of $38.37.

Morgan Stanley performed a comparable company trading analysis, which attempts to provide an implied value of a company by comparing it to similar companies that are publicly traded. Morgan Stanley reviewed and compared, using publicly available financial information, certain future financial information for Summit with corresponding future financial information, ratios and public market multiples for publicly traded companies in the heavy building materials space that shared certain similar business and operating characteristics to Summit.

These companies were chosen based on Morgan Stanley’s knowledge of the industry and because they have businesses that may be considered similar to Summit’s business. Although none of such companies are identical or directly comparable to Summit, these companies are publicly traded companies with operations and/or other criteria, such as lines of business, markets, business risks, growth prospects, maturity of business and size and scale of business, that, for purposes of its analysis, Morgan Stanley considered similar to Summit.

For purposes of this analysis, for each of the selected publicly traded companies listed below, Morgan Stanley analyzed the ratio of the AV of such company to its EBITDA for each of calendar years 2023 and 2024. Morgan Stanley calculated the estimated implied equity value of Summit based on (i) the AV/EBITDA multiples for each of the selected companies for calendar year 2023, multiplied by Summit’s estimated EBITDA for calendar year 2023 of $582 million, based on the Summit financial projections, and of $560 million, based on the median estimate as of September 1, 2023 per Thomson consensus projections, and (ii) the AV/EBITDA multiples for each of the selected companies for calendar year 2024, multiplied by Summit’s estimated EBITDA for calendar year 2024 of $641 million, based on the Summit financial projections, and of $616 million, based on the median estimate as of September 1, 2023 per Thomson consensus projections, as adjusted by Summit’s estimated net debt as of December 31, 2023, as provided by Summit’s management. Morgan Stanley then divided the resulting implied equity values by Summit’s fully diluted shares outstanding, as provided by Summit’s management, to derive implied equity values per share of Summit. The statistics for each of the selected companies and the corresponding estimated implied value per share (rounded to the nearest $0.25 per share) are summarized as follows:

Morgan Stanley compared these estimated implied values per share to the closing trading price of Class A Common Stock on September 1, 2023, the last trading day prior to the date of Morgan Stanley’s presentation to the Board, of $38.37.

No company utilized in the comparable company analysis is identical to Summit. In evaluating comparable companies, Morgan Stanley made judgments and assumptions with regard to industry performance, general business, economic, market and financial conditions, and other matters, many of which are beyond the control of Summit. These include, among other things, comparable company growth, the impact of competition on the businesses of Summit and the industry generally, industry growth and the absence of any adverse material change in the financial condition and prospects of Summit or the industry, or in the financial markets in general. Mathematical analysis (such as determining the mean) is not in itself a meaningful method of using comparable company data.

For reference purposes only, and not as a component of its fairness analysis, Morgan Stanley reviewed the historical trading data of shares of Class A Common Stock for the 52-week period ending September 1, 2023, and noted that, during such period, the highest intraday trading price per share of Class A Common Stock was $39.56 and the lowest intraday trading price per share of Class A Common Stock was $22.80.

For reference purposes only, and not as a component of its fairness analysis, Morgan Stanley reviewed the undiscounted price targets for shares of Class A Common Stock as of September 1, 2023 prepared by 14 equity

research analysts, as published in Capital IQ. These targets generally reflect each analyst’s estimate of the future public market trading price of shares of Class A Common Stock. The range of equity analyst undiscounted price targets for Class A Common Stock was $37.00 per share to $50.00 per share. Morgan Stanley also noted that the median of equity analyst undiscounted price targets for Class A Common Stock was $43.00 per share of Class A Common Stock.

The price targets published by equity research analysts do not necessarily reflect current market trading prices for Class A Common Stock and these estimates are subject to uncertainties, including the future financial performance of Summit and future financial market conditions.

Morgan Stanley calculated the estimated implied ownership percentage range for Cementos Argos implied by the discounted cash flow analyses described above under “— Analyses Relating to Summit — Discounted Cash Flow Analysis” and “— Analyses Relating to Argos USA — Discounted Cash Flow Analysis.” Morgan Stanley calculated the low end of the implied ownership percentage range by dividing the lowest implied enterprise value for Argos USA based on the Argos Base Case, less the estimated $1.2 billion of cash consideration to be paid to Argos USA stockholders at the completion of the Transaction, by the highest implied equity value for Summit. Morgan Stanley calculated the high end of the implied ownership percentage range by dividing the highest implied enterprise value for Argos USA based on the Argos Base Case, less the estimated $1.2 billion of cash consideration to be paid to Argos USA stockholders at the completion of the Transaction, by the lowest implied equity value for Summit. This analysis resulted in an implied cash adjusted ownership percentage range for Cementos Argos (rounded to one decimal place) of 28.2% to 49.1%, which Morgan Stanley compared to the cash-adjusted ownership percentage for Cementos Argos implied by the Consideration of 31.0%.

Morgan Stanley conducted a DCF analysis of Summit pro forma for the proposed Transaction, which is referred to in this section of the proxy statement as the pro forma DCF, using the projections for Summit and Argos USA and other information and data for each of Summit and Argos USA as described above and provided by Summit. The pro forma DCF analysis reflected (i) the mid-point of the ranges of stand-alone DCF values derived for each of Summit and Argos USA (based on the Argos Base Case), in each case as described above under “—Analyses Relating to Summit—Discounted Cash Flow Analysis” and “—Analyses Relating to Argos USA—Discounted Cash Flow Analysis,” respectively, plus (ii) the incremental value of net combination benefits as reflected by the mid-point of the range of the DCF values of Argos USA (based on the Synergized Case), minus (iii) the estimated $1.2 billion of cash consideration to be paid to Argos USA stockholders at the completion of the Transaction. Morgan Stanley then divided the resulting implied total equity value ranges by Summit’s pro forma fully diluted shares outstanding, calculated as Summit’s fully diluted shares outstanding, as provided by Summit’s management, as adjusted for newly issued shares in the Transaction. Based on the above-described analysis, Morgan Stanley derived a pro forma implied equity value per share of Class A Common Stock of $46.47. Morgan Stanley compared the pro forma implied equity value per share of Class A Common Stock to the stand-alone implied equity values per share of Class A Common Stock, as described above under “— Analyses Relating to Summit — Discounted Cash Flow Analysis.” Based on this analysis, the proposed Transaction would be accretive to Summit’s DCF equity value per share at the value implied by the DCF analysis.

Morgan Stanley also performed a discounted equity value analysis pro forma for the proposed Transaction. As part of this analysis, Morgan Stanley calculated future ranges of implied equity values per share of Class A Common Stock pro forma for the proposed Transaction as of each of January 1, 2026, January 1, 2027 and January 1, 2028, respectively, and subsequently discounted each such theoretical future value range to arrive at an illustrative present value range of implied share prices for Class A Common Stock pro forma for the proposed Transaction as of December 31, 2023.

To calculate the future ranges of pro forma implied equity values, Morgan Stanley applied a range of NTM AV/EBITDA multiples of 8.5x to 10.5x, derived by Morgan Stanley using its experience and professional judgment, to Summit’s estimated NTM AV/EBITDA, pro forma for the proposed Transaction, as of each of January 1, 2026, January 1, 2027 and January 1, 2028, in each case based on the Summit financial projections and the Argos USA financial projections (based on the Synergized Case), and then subtracted the amount of

Summit’s estimated net debt pro forma for the proposed transaction as of each date, respectively, as provided by Summit’s management. Morgan Stanley then divided the resulting pro forma implied equity values by Summit’s pro forma fully diluted shares outstanding (as adjusted for newly issued shares in the Transaction) to derive ranges of future pro forma implied equity values per share. Morgan Stanley then discounted the resulting pro forma implied equity values per share to December 31, 2023 at a discount rate equal to 11.0%, which discount rate was selected by Morgan Stanley based upon its professional judgment and taking into account Summit’s assumed cost of equity of 11.0%.

Based on this analysis, Morgan Stanley derived a range of pro forma implied equity values per share of Class A Common Stock of $40.01 to $54.13.

Morgan Stanley compared this pro forma implied equity value per share range to the stand-alone implied equity values per share of Class A Common Stock, as described above under “— Analyses Relating to Summit — Discounted Equity Value Analysis.” Based on this analysis, the proposed Transaction would be accretive to Summit’s discounted equity value per share at the value implied by the discounted equity value analysis.

In connection with the review of the proposed Transaction by the Board, Morgan Stanley performed a variety of financial and comparative analyses for purposes of rendering its opinion. The preparation of a financial opinion is a complex process and is not necessarily susceptible to a partial analysis or summary description. In arriving at its opinion, Morgan Stanley considered the results of all of its analyses as a whole and did not attribute any particular weight to any analysis or factor it considered. Morgan Stanley believes that selecting any portion of its analyses, without considering all analyses as a whole, would create an incomplete view of the process underlying its analyses and opinion. In addition, Morgan Stanley may have given various analyses and factors more or less weight than other analyses and factors and may have deemed various assumptions more or less probable than other assumptions. As a result, the ranges of valuations resulting from any particular analysis described above should not be taken to be Morgan Stanley’s view of the actual value of Argos USA or Summit. In performing its analyses, Morgan Stanley made numerous assumptions with respect to industry performance, general business, economic, market and financial conditions and other matters, many of which are beyond the control of Argos USA or Summit. Any estimates contained in Morgan Stanley’s analyses are not necessarily indicative of future results or actual values, which may be significantly more or less favorable than those suggested by such estimates.

Morgan Stanley conducted the analyses described above solely as part of its analysis of the fairness from a financial point of view to Summit of the Consideration to be paid by Summit pursuant to the Transaction Agreement and in connection with the delivery of its opinion, dated September 5, 2023, to the Board. These analyses do not purport to be appraisals or to reflect the prices at which shares of Class A Common Stock might actually trade.

The Consideration to be paid by Summit pursuant to the Transaction Agreement was determined through arm’s-length negotiations between Argos USA and Summit and was unanimously approved by the Board. Morgan Stanley provided advice to the Board during these negotiations but did not, however, recommend any specific consideration to Summit or the Board or that any specific consideration constituted the only appropriate consideration for the Transaction.

Morgan Stanley’s opinion and its presentation to the Board was one of many factors taken into consideration by the Board in deciding to approve, adopt and authorize the Transaction Agreement and the transactions contemplated thereby. Consequently, the analyses described above should not be viewed as determinative of the opinion of the Board with respect to the Consideration pursuant to the Transaction Agreement or of whether the Board would have been willing to agree to different consideration. Morgan Stanley’s opinion was approved by a committee of Morgan Stanley investment banking and other professionals in accordance with Morgan Stanley’s customary practice.

The Board retained Morgan Stanley based upon Morgan Stanley’s qualifications, experience and expertise. Morgan Stanley is a global financial services firm engaged in the securities, investment management and individual wealth management businesses. Morgan Stanley’s securities business is engaged in securities underwriting, trading and brokerage activities, foreign exchange, commodities and derivatives trading, prime brokerage, as well as providing investment banking, financing and financial advisory services. Morgan Stanley,

its affiliates, directors and officers may at any time invest on a principal basis or manage funds that invest, hold long or short positions, finance positions, and may trade or otherwise structure and effect transactions, for their own account or the accounts of their customers, in debt or equity securities or loans of Argos USA, Summit, or any other company, or any currency or commodity, that may be involved in the proposed Transaction, or any related derivative instrument.

Under the terms of its engagement letter, Morgan Stanley provided the Board with financial advisory services and a fairness opinion, described in this section and attached to this proxy statement as Annex K, in connection with the proposed Transaction, and Summit has agreed to pay Morgan Stanley a fee for its services of $30 million, $7.5 million of which was payable as of Morgan Stanley’s delivery of its fairness opinion and the remainder of which is payable if the Transaction is consummated. Summit has also agreed to reimburse Morgan Stanley for certain of its expenses, including reasonable fees of outside counsel and other professional advisors, incurred in connection with its engagement. In addition, Summit has agreed to indemnify Morgan Stanley and its affiliates, their respective officers, directors, employees and agents, and each other person, if any, controlling Morgan Stanley or any of its affiliates against certain losses, claims, damages and liabilities, including liabilities under the federal securities laws, related to or arising out of Morgan Stanley’s engagement. Affiliates of Morgan Stanley are also entitled to receive fees in connection with the transactions contemplated by the commitment letter for the debt financing relating to the Transaction.

Morgan Stanley holds an aggregate interest of less than 1% in the common stock of each of Summit, Cementos Argos, Grupo Argos, and Grupo de Inversiones Suramericana S.A., which interests are held in connection with Morgan Stanley’s (i) investment management business, (ii) wealth management business, including client discretionary accounts, or (iii) ordinary course trading activities, including hedging activities. In the two years prior to the date of its opinion, Morgan Stanley and its affiliates (i) have provided certain financing services to Summit and have received aggregate fees of less than $1 million in connection with such services and (ii) have not received any fees from Argos USA, Cementos Argos, Grupo Argos and the majority-controlled affiliates and portfolio companies of Grupo Argos that Morgan Stanley have been able to identify, for financial advisory or financing services. Morgan Stanley and its affiliates may in the future also seek to provide other financial advisory and financing services to Summit, Argos USA and their respective affiliates, and would expect to receive fees for the rendering of these services.

Upon completion of the Transaction, 54,720,000 shares of Class A Common Stock and one share of Preferred Stock will be issued to the Cementos Argos as partial consideration for the Purchased Shares to be acquired by Summit pursuant to the Transaction Agreement. As such, it is anticipated that Summit’s current stockholders will own approximately 69% of Summit and Cementos Argos will own, in the aggregate, approximately 31% of Summit after the closing of the Transaction.

Appraisal rights are not available to Summit’s stockholders in connection with the Transaction.

The Transaction will be accounted for using the acquisition method of accounting for business combinations. The allocation of the preliminary estimated Closing Consideration is based upon management’s estimates of and assumptions related to the fair value of assets to be acquired and liabilities to be assumed. Summit expects to finalize its allocation of the Closing Consideration as soon as practicable after completion of the Transaction, but Summit is not required to finalize such allocation for one year from the closing date of the Transaction. For U.S. federal income tax purposes, the Transaction will be treated as a stock purchase such that Summit’s tax basis in the Argos USA assets will initially be valued at carryover basis.

Under the HSR Act and the rules that have been promulgated thereunder by the FTC, certain transactions may not be consummated unless information has been furnished to the Antitrust Division and the FTC and certain waiting period requirements have been satisfied. The Transaction is subject to these requirements and may not be completed until the expiration of a 30-day waiting period following the filing of the required Notification

and Report Forms with the Antitrust Division and the FTC. If the FTC or the Antitrust Division makes a request for additional information or documentary material related to the Transaction (a “Second Request”), the waiting period with respect to the Transaction will be extended for an additional period of 30 calendar days, which will begin on the date on which Summit and Argos USA each certify compliance with the Second Request. Complying with a Second Request can take a significant period of time. On September 21, 2023, Summit and Argos USA filed the required forms under the HSR Act with the Antitrust Division and the FTC. The 30-day waiting period with respect to the Transaction, which cannot expire on a Saturday, Sunday or a U.S. federal holiday, expires at 11:59 p.m. Eastern Time on October 23, 2023 unless the FTC and the Antitrust Division, unless otherwise extended or terminated.

At any time before or after consummation of the Transaction, notwithstanding expiration of the waiting period under the HSR Act, the applicable competition authorities could take such action under applicable antitrust laws as each deems necessary or desirable in the public interest, including seeking to enjoin the consummation of the Transaction. Private parties may also seek to take legal action under the antitrust laws under certain circumstances. We cannot assure you that the Antitrust Division, the FTC, any state attorney general or any other government authority will not attempt to challenge the Transaction on antitrust grounds, and, if such a challenge is made, we cannot assure you as to its result.

Under the deferred prosecution agreement (the “DPA”) between Argos USA and the Department of Justice (the “DOJ”), dated January 4, 2021, notification to and consent of the Antitrust Division is required in connection with the Transaction. Under a compliance agreement between Argos USA LLC and the Federal Highway Administration, dated June 13, 2023, notification to the Federal Highway Administration is required in connection with the Transaction.

Neither Summit nor the Argos Parties is aware of any material regulatory approvals or actions that are required for completion of the Transaction other than the expiration of the waiting period under the HSR Act. It is presently contemplated that if any such additional regulatory approvals or actions are required, those approvals or actions will be sought. There can be no assurance, however, that any additional approvals or actions will be obtained.

A portion of the consideration to be paid to Cementos Argos (on behalf of the Argos Parties) in connection with the Transaction will be the Stock Consideration, which consists of (i) the Class A Consideration and (ii) the Preferred Share.

Summit’s stockholders are being asked to approve the issuance of the Class A Consideration pursuant to the terms of the Transaction Agreement in connection with the Transaction. Summit’s stockholders should carefully read this proxy statement in its entirety for more detailed information concerning the Transaction Agreement, which is attached as Annex A to this proxy statement. Please see the section entitled “The Transaction” above for additional information and a summary of certain terms of the Transaction Agreement. You are urged to carefully read the Transaction Agreement in its entirety before voting on this proposal.

We may consummate the Transaction only if this Common Stock Issuance Proposal is approved by the affirmative vote of a majority of the voting power of the outstanding shares of our Common Stock present in person or represented by proxy and entitled to vote at the Special Meeting.

Summit is seeking stockholder approval in order to comply with NYSE Listing Rule 312.03. Under NYSE Listing Rule 312.03, stockholder approval is required prior to the issuance of common stock or other securities convertible into or exercisable for common stock, in connection with any transaction or series of related transactions if (i) the common stock has, or will have upon issuance, voting power equal to or in excess of 20% of the voting power outstanding before the issuance of such stock or of securities convertible into or exercisable for common stock; or (ii) the number of shares of common stock to be issued is or will be equal to or in excess of 20% of the number of shares of common stock outstanding before the issuance of the common stock or of securities convertible into or exercisable for common stock.

Pursuant to the terms and conditions of the Transaction Agreement, the aggregate consideration to be paid to the Argos Parties in the Transaction will consist of (i) $1.2 billion of cash (subject to customary adjustments), (ii) 54,720,000 shares of Class A Common Stock and (iii) one share of Preferred Stock. For more information on the closing adjustments to the Cash Consideration, please see the section above entitled “The Transaction — The Transaction Agreement.” Because the Stock Consideration constitutes voting power of Summit that exceeds 20% of the voting power outstanding before the Transaction and includes a number of shares to be issued that exceeds 20% of the number of shares of Common Stock outstanding before the Transaction, NYSE Listing Rule 312.03 requires Summit to obtain stockholder approval before completing the Transaction.

If the Common Stock Issuance Proposal is presented at the Special Meeting and is not approved by Summit’s stockholders, the chair of the Special Meeting may adjourn or postpone the Special Meeting to a later date only to the extent Summit believes in good faith that adjournment or postponement is reasonably necessary (i) to ensure that any required supplement or amendment to this Proxy Statement is delivered to the holders of Class A Common Stock and Class B Common Stock within a reasonable amount of time in advance of the Summit Stockholders Meeting, (ii) to allow reasonable additional time to solicit additional proxies necessary to obtain the Stockholder Approval (including after commencement of a Summit Acquisition Proposal that is a tender offer or exchange offer to the extent necessary to obtain the Stockholder Approval), (iii) to ensure that there are sufficient number of holders of Class A Common Stock and Class B Common Stock represented (either in person or by proxy) and voting to constitute a quorum necessary to conduct the business of the Summit stockholder meeting or (iv) otherwise where required to comply with applicable law following consultation with outside legal counsel.

If the Common Stock Issuance Proposal is adopted, 54,720,0000 shares of Class A Common Stock will be issued to Cementos Argos pursuant to the Transaction Agreement. The issuance of such shares would result in significant dilution to Summit’s stockholders, and would afford Summit’s stockholders a smaller percentage interest in the voting power, liquidation value and aggregate book value of the Company.

This Common Stock Issuance Proposal (and consequently, the Transaction and the transactions contemplated thereby) will be adopted and approved by the affirmative vote of a majority of the voting power of the outstanding shares of our Common Stock present in person or represented by proxy and entitled to vote at the Special Meeting, assuming a quorum is present. A stockholder’s failure to vote by proxy or to vote in person at the Special Meeting, as well as any broker non-vote with regard to the Common Stock Issuance Proposal, will have no effect on the outcome of the Common Stock Issuance Proposal. Abstentions will be counted in connection with the determination of whether a valid quorum is established, but will have the effect of a vote “AGAINST” the Common Stock Issuance Proposal.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT SUMMIT’S STOCKHOLDERS VOTE “FOR” THE COMMON STOCK ISSUANCE PROPOSAL.

A portion of the consideration to be paid to Cementos Argos (on behalf of the Argos Parties) in connection with the Transaction will be the Stock Consideration, which consists of (i) the Class A Consideration and (ii) the Preferred Share.

Summit’s stockholders are being asked to approve the issuance of the Preferred Share pursuant to the terms of the Transaction Agreement in connection with the Transaction. Summit’s stockholders should carefully read this proxy statement in its entirety for more detailed information concerning the Transaction Agreement, which is attached as Annex A to this proxy statement. Please see the section entitled “The Transaction” above for additional information and a summary of certain terms of the Transaction Agreement. You are urged to carefully read the Transaction Agreement in its entirety before voting on this proposal.

We may consummate the Transaction only if this Preferred Stock Issuance Proposal is approved by the affirmative vote of a majority of the voting power of the outstanding shares of our Common Stock present in person or represented by proxy and entitled to vote at the Special Meeting.

Summit is seeking stockholder approval in order to comply with NYSE Listing Rule 312.04. Under NYSE Listing Rule 312.04, stockholder approval is required prior to the issuance of stock or other securities convertible into or exercisable for common stock, in connection with any transaction or series of related transactions if  (i) the common stock has, or will have upon issuance, voting power equal to or in excess of 20% of the voting power outstanding before the issuance of such stock or of securities convertible into or exercisable for common stock; or (ii) the number of shares of common stock to be issued is or will be equal to or in excess of 20% of the number of shares of common stock outstanding before the issuance of the common stock or of securities convertible into or exercisable for common stock.

Pursuant to the terms and conditions of the Transaction Agreement, the aggregate consideration to be paid to the Argos Parties in the Transaction will consist of (i) $1.2 billion of cash (subject to customary adjustments), (ii) 54,720,000 shares of Class A Common Stock and (iii) one share of Preferred Stock. For more information on the closing adjustments to the Cash Consideration, please see the section above entitled “The Transaction — The Transaction Agreement.” Because the Stock Consideration includes one share of Preferred Stock that is convertible into or exercisable for Class A Common Stock which, together with the Class A Consideration, is in excess of 20% of the voting power outstanding before the Transaction, NYSE Listing Rule 312.04 requires Summit to obtain stockholder approval before completing the Transaction.

If the Preferred Stock Issuance Proposal is presented at the Special Meeting and is not approved by Summit’s stockholders, the chair of the Special Meeting may adjourn or postpone the Special Meeting to a later date only to the extent Summit believes in good faith that adjournment or postponement is reasonably necessary (i) to ensure that any required supplement or amendment to this Proxy Statement is delivered to the holders of Class A Common Stock and Class B Common Stock within a reasonable amount of time in advance of the Summit Stockholders Meeting, (ii) to allow reasonable additional time to solicit additional proxies necessary to obtain the Stockholder Approval (including after commencement of a Summit Acquisition Proposal that is a tender offer or exchange offer to the extent necessary to obtain the Stockholder Approval), (iii) to ensure that there are sufficient number of holders of Class A Common Stock and Class B Common Stock represented (either in person or by proxy) and voting to constitute a quorum necessary to conduct the business of the Summit stockholder meeting or (iv) otherwise where required to comply with applicable law following consultation with outside legal counsel.

If the Preferred Stock Issuance Proposal is adopted, the Preferred Share will be issued to Cementos Argos pursuant to the Transaction Agreement. The issuance of the Preferred Share, together with the Class A Consideration, would, if converted or exercised into Class A Common Stock, result in significant dilution to Summit’s stockholders, and would afford Summit’s stockholders a smaller percentage interest in the voting power, liquidation value and aggregate book value of the Company.

This Preferred Stock Issuance Proposal (and consequently, the Transaction and the transactions contemplated thereby) will be adopted and approved by the affirmative vote of a majority of the voting power of the outstanding shares of our Common Stock present in person or represented by proxy and entitled to vote at the Special Meeting, assuming a quorum is present. A stockholder’s failure to vote by proxy or to vote in person at the Special Meeting, as well as any broker non-vote with regard to the Preferred Stock Issuance Proposal, will have no effect on the outcome of the Preferred Stock Issuance Proposal. Abstentions will be counted in connection with the determination of whether a valid quorum is established, but will have the effect of a vote “AGAINST” the Preferred Stock Issuance Proposal.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT SUMMIT’S STOCKHOLDERS VOTE “FOR” THE PREFERRED STOCK ISSUANCE PROPOSAL.

The Adjournment Proposal will only be presented to our stockholders at the Special Meeting in the event that there are insufficient votes for, or otherwise in connection with, the approval of the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal.

If Summit’s stockholders approve the Adjournment Proposal, the chair of the Special Meeting, at the direction of the Board, could adjourn the Special Meeting, and any adjourned session of the Special Meeting, and use the additional time to solicit additional votes, including from Summit’s stockholders that have previously submitted proxies, to approve the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal. If the Adjournment Proposal is approved, the Special Meeting may be adjourned in the absence of a quorum by the affirmative vote of Common Stock present in person or by proxy. Even if a quorum is present, the Special Meeting could be adjourned in order to provide more time to solicit additional votes in favor of approval of the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal if a majority of votes are cast in favor of the Adjournment Proposal. Among other things, approval of the Adjournment Proposal could mean that, even if we had received proxies representing a sufficient number of votes to defeat the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal, we could adjourn the Special Meeting without a vote on the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal and seek to convince our stockholders to change their proxies in favor of the Common Stock Issuance Proposal and/or the Preferred Stock Issuance Proposal.

If the Special Meeting is adjourned, no notice of the adjourned meeting is required to be given to Summit’s stockholders, other than an announcement at the Special Meeting of the time and place to which the Special Meeting is adjourned. If, after the adjournment, a new record date is set for the adjourned meeting, a notice of the adjourned meeting must be given to each stockholder of record entitled to vote at the Special Meeting. If the Special Meeting is adjourned, stockholders who have already submitted their proxies will be able to revoke them at any time before their use.

If the Adjournment Proposal is presented at the Special Meeting and is not approved by Summit's stockholders, the chair of the Special Meeting may adjourn or postpone the Special Meeting to a later date only to the extent Summit believes in good faith that adjournment or postponement is reasonably necessary (i) to ensure that any required supplement or amendment to this Proxy Statement is delivered to the holders of Class A Common Stock and Class B Common Stock within a reasonable amount of time in advance of the Summit Stockholders Meeting, (ii) to allow reasonable additional time to solicit additional proxies necessary to obtain the Stockholder Approval (including after commencement of a Summit Acquisition Proposal that is a tender offer or exchange offer to the extent necessary to obtain the Stockholder Approval), (iii) to ensure that there are sufficient number of holders of Class A Common Stock and Class B Common Stock represented (either in person or by proxy) and voting to constitute a quorum necessary to conduct the business of the Summit stockholder meeting or (iv) otherwise where required to comply with applicable law following consultation with outside legal counsel.

The approval of the Adjournment Proposal requires the affirmative vote of a majority of the voting power of the outstanding shares of Common Stock present in person or represented by proxy and entitled to vote at the Special Meeting. Accordingly, a stockholder's failure to vote by proxy or to vote in person at the Special Meeting, as well as any broker non-vote with regard to the Adjournment Proposal, will have no effect on the outcome of the Adjournment Proposal. Abstentions will be counted in connection with the determination of whether a valid quorum is established, but will have the effect of a vote “AGAINST” the Adjournment Proposal.

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT SUMMIT’S STOCKHOLDERS VOTE “FOR” THE ADJOURNMENT PROPOSAL.

The presentation of Argos USA’s results of operations has been conformed for purposes of presenting comparable results. For full historical financial statements of Argos USA for the periods presented, please see the financial statements appearing elsewhere in this proxy statement.

Argos USA is the largest cement producer by total installed capacity in its areas of operations and among the leaders in sustainability within the heavy construction materials industry. Argos USA operates a robust, vertically integrated business model in the cement and ready-mix concrete segments, supported by an interconnected and efficient logistics platform of ports and terminals across the East and Gulf Coast regions of the United States.

Argos USA believes that its strong commitment to sustainability, combined with its rights in proprietary technology and experience in the production of low carbon cements and supplementary cementitious materials (“SCMs”) allows it to lead the industry in reducing emissions. It is one of the fastest growing companies in the industry, based on its Adjusted EBITDA growth since 2019, and is well positioned to capitalize on industry dynamics that are expected to drive long-term demand for its products. In 2022, it sold 6.1 million tons of cement and 5.8 million cubic yards of ready-mix concrete, which accounted for 49% and 51% of its revenue, respectively. In the six months ended June 30, 2023, it sold 3 million tons of cement and 2.8 million cubic yards of ready-mix concrete, which accounted for 50% and 50% of its revenue, respectively. In 2022, its net income and Adjusted EBITDA were $51.3 million and $203.0 million, respectively, and its cement and ready-mix concrete business generated $217.0 million and $27.5 million, respectively, of its segment Adjusted EBITDA before giving effect to corporate expenses and eliminations. In the six months ended June 30, 2023, its net income and Adjusted EBITDA were $50.72 million and $142.8 million, respectively, and its cement and ready-mix concrete business generated $133.9 million and $30.6 million, respectively, of its segment Adjusted EBITDA before giving effect to corporate expenses and eliminations. Its operations are vertically integrated: intercompany sales of its cement to its ready-mix concrete operations represented approximately 19% of its total cement volumes in 2022, and 18% for the six months ended June 30, 2023. Approximately 77% of the cement used in its ready-mix concrete business in 2022 and 80% for the six months ended June 30, 2023, was supplied by its cement production. In addition to its intercompany sales of cement, Argos USA also sells bulk cement to third-party ready-mix concrete producers, manufacturers of concrete products and resellers. Argos USA sells cement and mortar products to resellers and directly to customers in bagged form. Argos USA offers ready-mix concrete in a wide range of mixes specifically formulated for a broad range of uses. See “Argos USA’s Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Unaudited Pro Forma Condensed Combined Financial Information” for a definition of Adjusted EBITDA and a reconciliation of its Adjusted EBITDA to its net income.

Argos USA’s unique asset footprint is comprised of four integrated cement plants, two grinding facilities, 140 ready-mix concrete plants, eight ports and 10 inland terminals, with a total installed cement grinding capacity of 9.6 million tons per annum and a total import capacity of 5.4 million tons of cement per annum. Argos USA’s import capacity could effectively increase its total cement installed capacity by 50% when required to support its operations.

For example, its import facilities allow it to import cement from other countries. Its logistics platform allows it to transport its produced and imported cement inland and access a highly efficient supply chain of imported cement and building materials at competitive costs. This network of ports and inland terminals provides it flexibility to adjust to market conditions by enabling it to supply local markets with imports at a time when cement production in the United States is at near to full capacity due to increased cement consumption that is expected to continue in the long term despite challenges presented by rising interest rates and elevated inflation. Argos USA has strategically expanded its footprint over the last 18 years around key cities and economic hubs. As ready-mix concrete delivery is typically limited to a 90-minute window in which newly mixed ready-mix concrete must be poured to maintain quality and performance, it is difficult for another producer to replicate its commercial and operational structure, which allows it to effectively supply its regions. Moreover, its unique and integrated portfolio of assets allowed it to self-supply approximately 77% of the cement that it uses for its ready-mix concrete business in 2022.

Argos USA is among the leaders in sustainability in its industry with proven and recognized standards that form a core pillar of its business strategy. Argos USA believes that sustainability means creating value for both society and for the company itself. Argos USA is committed to creating value for its stakeholders and to the sustainable development of the company and the communities it serves.

Argos USA has strategically expanded its ready-mix concrete network over the last 17 years around key cities and economic hubs, which began in 2005 with acquisitions of ready-mix concrete plants in Texas and Arkansas. Argos USA continued to pursue acquisitions that expanded its geographic footprint, built a vertically integrated business model by entering cement production and scaled its logistics platform. Since its market entry, Argos USA has completed fifteen acquisitions with total investments of approximately $2.5 billion, net of divestments.

The cement and ready-mix production volumes grew at compound annual growth rates (“CAGRs”) of 71% and 14%, respectively, from 2011 to 2016, which allowed Argos USA to leverage its fixed-cost structure to achieve significant margin improvements. In 2017, it began optimizing its footprint through selected divestitures of non strategic assets and targeted cost efficiency initiatives, which led to improvements in profitability. Argos USA’s net income margin increased by 240 basis points, and the Adjusted EBITDA Margin increased by 290 basis points, in each case from 2019 to 2022. See “Argos USA’s Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Unaudited Pro Forma Condensed Combined Financial Information” for a definition of Adjusted EBITDA and a reconciliation of its Adjusted EBITDA to its net income.

Argos USA has intentionally built its unique platform across the most dynamic construction hubs and some of the fastest growing states in the United States. According to the Portland Cement Association, the states where Argos USA operates represent 49% of the total cement consumption in the country and 44% of the country’s population as of December 31, 2022. According to estimates by the Portland Cement Association and Dodge Construction Network, cement and ready-mix concrete consumption in our regions are expected to grow 5.6 million tons in cement from 2022 through 2027 and 53.2 million cubic yards in ready-mix concrete from 2022 through 2027 and provide it with an opportunity to execute our growth strategy.

Argos USA’s company office is located at 3015 Windward Plaza #300 Alpharetta, GA 30005 and its phone number for this office is (678) 368-4300.

The following discussion should be read in conjunction with the Argos USA audited consolidated and combined financial statements and the Argos USA unaudited interim consolidated and combined financial statements and corresponding notes. Any forward-looking statements are not historical facts, but rather are based on current expectations, estimates, assumptions and projections about our industry, business and future financial results. Any forward-looking statements are subject to a number of important factors that could cause our actual results to differ materially from those indicated in such forward-looking statements.

We are the largest cement producer by total installed capacity in our areas of operations and among the leaders in sustainability within the heavy construction materials industry. We operate a robust vertically integrated business model in the cement and ready-mix concrete segments, supported by an interconnected and efficient logistics platform of ports and terminals across the East and Gulf Coast regions of the United States. We believe that our strong commitment to sustainability, combined with our proprietary technology and experience in the production of low carbon cements and SCMs, will allow us to lead the industry in reducing emissions. We are one of the fastest growing companies in our industry, based on our Adjusted EBITDA growth since 2019, and we are well positioned to capitalize on industry dynamics that are expected to drive long-term demand for our products.

Our unique asset footprint is comprised of four integrated cement plants, two cement grinding facilities, 140 ready-mix concrete plants, eight ports and 10 inland terminals, with a total installed cement grinding capacity of 9.6 million tons per annum and a total import capacity of 5.4 million tons per annum of cement.

Our core products are cement and ready-mix concrete. For the year ended December 31, 2022, cement and ready-mix concrete accounted for 49% and 51% of our revenues, respectively. The proportion of revenues related to cement and ready-mix concrete was 50% and 50%, respectively, for the six months ended June 30, 2023, compared to 47% and 53%, respectively, for the six months ended June 30, 2022. Our operations are vertically integrated and, for the year ended December 31, 2022 and the six months ended June 30, 2023, intercompany sales of cement to our ready-mix concrete production operations represented approximately 19% and 18% respectively of our total cement volumes. We also sell cement to third-party ready-mix concrete producers, manufacturers of concrete products, resellers and directly to customers in bagged form.

In addition, we offer ready-mix concrete in a range of mixes specifically formulated for commercial, residential, highway/civil, and homeowner/DIY uses, as well as custom concrete mixes and additives. Our ready-mix concrete customers primarily include general contractors, sub-contractors and finishers.

In addition to our cement and ready-mix products, our long-term plan includes expanding into the aggregates market and complementary business lines, including SCMs.

We have intentionally built our platform across the most dynamic construction hubs and some of the fastest growing states in the United States. We currently operate across 16 states throughout the East and Gulf Coast regions of the United States and the District of Columbia, as shown in the map below. Our total cement grinding capacity of approximately 9.6 million tons per annum across five states positions us with approximately 17% of the total cement grinding capacity in the states where we operate, the largest across these states. In addition, our eight ports and 10 inland terminals provide a total import capacity of 5.4 million tons of cement per annum, which could effectively increase our total cement installed capacity by 50% when required to support our operations. For example, our import facilities allow us to import cement from other countries, including from the Cartagena Plant, owned by a subsidiary of Cementos Argos, our Colombian parent company and principal stockholder. Our cement sales are diversified, with Florida, North Carolina, South Carolina, Georgia, Virginia, Alabama, Maryland, Texas and Ohio comprising approximately 88% of our cement revenues in 2022, and our ready-mix sales are concentrated in Florida, Georgia, North Carolina, South Carolina and Texas, which comprised approximately 99% of our revenues in our ready-mix concrete segment in 2022.

According to data from the USGS and National Ready Mixed Concrete Association, the estimated market for 2022 for cement, ready-mix concrete and aggregates in the United States totaled $15.6 billion, $68.0 billion and $33.0 billion, respectively. We operate in the cement and ready-mix concrete sectors of the heavy construction materials industry in the United States, primarily in the East and Gulf Coast regions. Our operating results are highly dependent upon activity within the construction industry, economic cycles within the public and private sectors, volume and price variance, seasonality and weather-related conditions. The following provides summaries of factors affecting our revenues and costs.

We primarily serve customers in three end markets: infrastructure, commercial construction and residential construction. We expect to see long-term positive momentum across these end markets arising from several key trends:

We have substantial fixed and semi-fixed costs, the variances for which are driven largely by energy, labor and cement costs. Accordingly, our financial results for any year presented, or year-to-year comparisons of reported results, may not be indicative of future operating results.

Our future results of operations may not be comparable to our historical results of operations presented in the Argos USA audited consolidated and combined financial statements and unaudited interim consolidated and combined financial statements included elsewhere in this document for the reasons described below:

In addition to our financial results, we use sales volumes as a key performance indicator to evaluate our business and identify trends affecting our business.

Cement volumes include cementitious products sold to third parties, either produced by our own plants or purchased from third parties, expressed in tons. Cement volumes also include intercompany sales of cement to our ready-mix operations and any cement we purchase from third parties and use in our ready-mix operations. Ready-mix volumes include ready-mix concrete produced by our ready-mix plants and sold to third parties, expressed in cubic yards. Historical ready-mix volumes reflect plants that we owned as of June 30, 2023, adjusted for the 2022 Disposal, the 2021 Disposal, and the 2019 Disposal.

We evaluate our operating performance using metrics that are referred to as “Adjusted Revenues,” “Adjusted EBITDA” and “Adjusted EBITDA Margin,” which are not defined by U.S. GAAP and should not be considered as alternatives to the earnings measures defined by U.S. GAAP. We utilize these metrics, among others, to assess our operating performance and to provide a consistent comparison of performance from period to period and as a basis for strategic planning and forecasting as we believe that it closely correlates to long-term enterprise value. We believe that measuring performance on an Adjusted Revenues, Adjusted EBITDA and Adjusted EBITDA Margin basis is useful to investors because it enables a more consistent evaluation of our operational performance period to period.

The adjustments for the 2022 Disposal and 2021 Disposal reflect how management evaluates the Company’s business given that the Company’s ready-mix concrete business no longer services (or recognizes revenue) in the geographic areas in which the disposals were located. We include these adjustments to enhance comparability of current results to prior period results. Adjusted Revenues, Adjusted EBITDA and Adjusted EBITDA Margin have limitations as analytical tools and should not be considered in isolation or as substitutes for an analysis of our results as reported under U.S. GAAP. Because of these limitations, Adjusted Revenues, Adjusted EBITDA and Adjusted EBITDA Margin should not be considered as replacements for revenues, Net income, Net income margin, as determined by U.S. GAAP, or as measures of our profitability. We compensate for these limitations by relying primarily on our U.S. GAAP results and using non-GAAP measures only for supplemental purposes.

The components of our operating results consist of (i) revenues predominantly from the sale of cement and ready-mix concrete products; (ii) cost of goods sold consisting of all direct production costs, including labor, materials, transportation and fuel; (iii) selling, general and administrative expenses including salaries and related costs for roles not directly attributable to the production of goods sold, such as sales and marketing, legal, finance and accounting, information technology, human resources and certain other employees; (iv) net (gain) loss on disposals relating to the disposal and retirement of certain ready-mix concrete assets and liabilities; (v) certain interest expenses; and (vi) federal and state income taxes related to the tax jurisdictions in which we do business.

As discussed in more detail below, our operating results are highly dependent upon activity within the construction industry, economic cycles within the public and private business sectors, volume and price variances, and seasonality. Accordingly, financial results for any period presented, or period-to-period comparisons of reported results, may not be indicative of future operating results.

Our financial results for the three and six months ended June 30, 2023 and 2022 and the years ended December 31, 2022, 2021, and 2020 were not materially affected by the extraordinary and wide-ranging actions taken by international, federal, state and local public health and governmental authorities to contain and combat the spread of COVID-19. However, our financial results for the year ended December 31, 2022 were affected by rising interest rates, energy costs and inflation, which continued through the three and six months ended June 30, 2023. Nevertheless, the extent to which the global economic challenges will ultimately impact our business, operations, financial condition and results of operations will depend on numerous factors, which are highly uncertain, rapidly changing, and cannot be predicted.

The table below sets forth a summary of our results of operations for the three and six months ended June 30, 2023 and 2022:

The tables below include Adjusted Revenues, Adjusted EBITDA and Adjusted EBITDA Margin, as well as the reconciliations to the closest comparable U.S. GAAP metric, for the periods indicated:

Revenues for the three months ended June 30, 2023 were $444.1 million, an increase of $27.9 million, or 6.7%, from $416.2 million for the three months ended June 30, 2022. The proportion of revenues related to cement and ready-mix concrete was 50.8% and 49.2%, respectively, for the three months ended June 30, 2023, compared to 49.5% and 50.5%, respectively, for the three months ended June 30, 2022. The increase in our overall revenues for the three months ended June 30, 2023 was driven by an increase in cement and ready-mix concrete revenues of $19.6 million and $8.3 million, respectively, primarily due to increases in selling prices. The increase in revenues was partially offset by a decrease in revenues due to an equipment failure in our Newberry, Florida cement plant resulting in a loss of approximately 42,100 tons during the three months ended June 30, 2023.

Revenues for ready-mix concrete for the three months ended June 30, 2023 were $218.4 million, an increase of $8.3 million, or 4.0%, from $210.1 million for the three months ended June 30, 2022. This increase primarily relates to favorable selling prices of $34.7 million, partially offset by unfavorable sales volumes of $26.4 million.

Revenues for cement for the three months ended June 30, 2023 were $225.7 million, an increase of $19.6 million or 9.5% from $206.1 million for the three months ended June 30, 2022. This increase primarily relates to favorable selling prices of $28.4 million for the three months ended June 30, 2023, partially offset by unfavorable sales volumes of $8.8 million, driven by an equipment failure in our Newberry, Florida cement plant resulting in a loss of approximately 42,100 tons during the three months ended June 30, 2023.

Cost of goods sold for the three months ended June 30, 2023 was $348.5 million, a decrease of $1.1 million, or 0.3%, from $349.6 million for the three months ended June 30, 2022. The decrease in cost of goods sold was primarily driven by a $1.7 million decrease in power and fuel costs and a reduction in sales volume, partially offset by rising material, delivery and plant costs. The reduction in sales volume was driven by an equipment failure at our Newberry, Florida cement plant. Cost of goods sold as a percentage of revenues was 78.5% and 84.0% for the three months ended June 30, 2023 and 2022, respectively. The proportion of cost of goods sold related to cement and ready-mix concrete was 49.5% and 50.5%, respectively, for the three months ended June 30, 2023, compared to 48.6% and 51.4%, respectively, for the three months ended June 30, 2022.

Cost of goods sold for ready-mix concrete for the three months ended June 30, 2023 was $175.9 million, a decrease of $3.7 million, or 2.1%, from $179.6 million for the three months ended June 30, 2022. This decrease primarily relates to lower sales volume resulting in lower cost of goods sold of $22.6 million, partially offset by rising material, delivery and plant costs of $18.9 million.

Cost of goods sold for cement for the three months ended June 30, 2023 was $172.6 million, an increase of $2.6 million, or 1.5%, from $170.0 million for the three months ended June 30, 2022. This increase was

primarily driven by higher direct costs such as manufacturing expense, freight costs, direct labor and materials of $9.2 million, which includes lower power and fuel costs of $1.2 million. This increase was partially offset by lower sales volume resulting in lower cost of goods sold of $6.6 million for the three months ended June 30, 2023. The lower sales volume was driven by an equipment failure in our Newberry, Florida cement plant during the three months ended June 30, 2023.

Selling, general and administrative expenses for the three months ended June 30, 2023 were $37.4 million, an increase of $3.0 million, or 8.7%, from $34.4 million for the three months ended June 30, 2022. Selling, general and administrative expenses as a percentage of revenues were 8.4% and 8.3% for the three months ended June 30, 2023 and 2022, respectively. The increase in selling, general and administrative expenses for the three months ended June 30, 2023 was driven primarily by an increase in labor costs and performance-based compensation, partially offset by a reduction in third-party consulting fees and bad debt expense.

Selling, general and administrative expenses of ready-mix concrete for the three months ended June 30, 2023 were $13.9 million, an increase of $3.8 million, or 37.6%, from $10.1 million for the three months ended June 30, 2022. The increase in selling, general and administrative expenses for the three months ended June 30, 2023 was driven primarily by an increase in performance-based compensation, partially offset by a decrease in bad debt expense.

Selling, general and administrative expenses of cement for the three months ended June 30, 2023 were $11.8 million, an increase of $5.0 million, or 73.5%, from $6.8 million for the three months ended June 30, 2022. The increase in selling, general and administrative expenses for the three months ended June 30, 2023 was driven primarily by an increase in labor costs, performance-based compensation, and third-party consulting fees.

Other income, net is comprised of rental revenue and other miscellaneous items. Other income, net for the three months ended June 30, 2023 was $0.2 million, a decrease of $4.0 million from $4.2 million for the three months ended June 30, 2022. This decrease primarily relates to a decrease in miscellaneous income, offset by rental revenue.

Net gain on disposals for the three months ended June 30, 2023 was $1.1 million, a decrease of $20.9 million from $22.0 million for the three months ended June 30, 2022. This decrease was driven primarily by the gain on the 2022 Disposal which was recognized during the three months ended June 30, 2022.

Net gain on disposals of ready-mix concrete for the three months ended June 30, 2023 was $1.1 million, a decrease of $21.0 million from $22.1 million for the three months ended June 30, 2022. This decrease was driven primarily by the gain on the 2022 Disposal which was recognized during the three months ended June 30, 2022.

Net gain on disposals for cement for the three months ended June 30, 2023 and 2022 consisted of asset sales and retirements in the normal course of operations resulting in an immaterial amount recognized.

Interest expense, net for the three months ended June 30, 2023 was $10.2 million, an increase of $1.2 million, or 13.3%, from $9.0 million for the three months ended June 30, 2022. This increase primarily relates to rising interest rates.

Income tax expense for the three months ended June 30, 2023 was $12.1 million, a decrease of $8.9 million from $21.0 million for the three months ended June 30, 2022. This decrease primarily relates to the non-deductible goodwill included in the 2022 Disposal.

Revenues for the six months ended June 30, 2023 were $860.7 million, an increase of $84.9 million, or 10.9%, from $775.8 million for the six months ended June 30, 2022. The proportion of revenues related to cement and ready-mix concrete was 49.8% and 50.2%, respectively, for the six months ended June 30, 2023,