SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-14

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Pre-Effective Amendment No. ☐

Post-Effective Amendment No. ☐

MASSMUTUAL PREMIER FUNDS

(Exact Name of Registrant as Specified in Declaration of Trust)

1295 State Street, Springfield, MA 01111-0001

(413) 744-1000

Name and Address of Agent for Service

Andrew M. Goldberg, Esq.

Vice President, Secretary, and Chief Legal Officer

MassMutual Premier Funds

1295 State Street

Springfield, MA 01111-0001

Copy to:

Brian McCabe, Esq.

Ropes & Gray LLP

Prudential Tower

800 Boylston Street

Boston, MA 02199-3600

TITLE OF SECURITIES BEING REGISTERED:

Classes I, R5, Service Class, Administrative Class, R4, A, R3, and Y of the MassMutual Core Bond Fund, a series of the Registrant.

Approximate date of proposed public offering: As soon as practicable after this Registration Statement becomes effective.

It is proposed that this filing will become effective on July 5, 2025 pursuant to Rule 488.

An indefinite amount of the Registrant’s securities has been registered under the Securities Act of 1933 pursuant to Rule 24f-2 under the Investment Company Act of 1940. In reliance upon such Rule, no filing fee is being paid at this time.

MassMutual Select Funds

MassMutual Equity Opportunities Fund

MassMutual Total Return Bond Fund

(Each, a “Selling Fund” and collectively, the “Selling Funds”)

IMPORTANT NOTICE OF

COMBINED INFORMATION STATEMENT/PROSPECTUS

This notice presents only an overview of the more complete Combined Information Statement/Prospectus that is available to you on the Internet relating to the reorganization (each, a “Reorganization” and collectively, the “Reorganizations”) of each Selling Fund into another fund (each, an “Acquiring Fund” and together, the “Acquiring Funds”) managed by MML Investment Advisers, LLC (“MML Advisers”). The Selling Funds and Acquiring Funds are referred to collectively as the “Funds.” As previously communicated in a supplement to your Fund’s prospectus, MML Advisers proposed the Reorganizations to the Boards of Trustees of the Selling Funds and the Acquiring Funds (the “Boards”), and the Boards unanimously approved each Reorganization. In accordance with each Fund’s Amended and Restated Agreement and Declaration of Trust (each, a “Declaration of Trust”) and applicable state and U.S. federal law (including Rule 17a-8 under the Investment Company Act of 1940, as amended), each Reorganization may be effected without the approval of shareholders of a Fund. Although shareholder approval is not required for the Reorganization of your Fund, we encourage you to access and review all of the important information contained in the Combined Information Statement/Prospectus.

Under the Agreement and Plan of Reorganization, each Selling Fund, as indicated below, will transfer that portion of its assets attributable to each class of its shares (in aggregate, all of its assets) to the corresponding Acquiring Fund, as indicated below, in exchange for shares of the same class of shares of the Acquiring Fund and the assumption by the Acquiring Fund of all the liabilities of the corresponding Selling Fund. Each Reorganization is expected to close on or about September 15, 2025. If you are a shareholder of the Selling Fund immediately prior to the closing, you will become a shareholder of the corresponding Acquiring Fund.

The table below shows each Selling Fund and the corresponding Acquiring Fund for each Reorganization. Each Selling Fund is a series of MassMutual Select Funds (MassMutual Select Funds, with respect to the Selling Funds, the “Selling Trust”). Each Acquiring Fund is a series of MassMutual Select Funds or MassMutual Premier Funds, as indicated in the table below (each, with respect to the Acquiring Funds, an “Acquiring Trust” and together, the “Acquiring Trusts”). Each Selling Fund and Acquiring Fund offers the same classes of shares: Class I, Class R5, Service Class, Administrative Class, Class R4, Class A, Class R3, and Class Y¹.

The Reorganization of each Selling Fund into the Acquiring Fund will enable shareholders of each Selling Fund to invest in a larger, potentially more efficient portfolio while continuing to pursue a substantially similar or comparable investment objective. The Reorganizations are also part of a larger effort intended, among other things, to streamline the mutual funds managed by MML Advisers and its affiliates (the “MassMutual Funds”) by reducing the number of funds in the MassMutual Fund complex so that management, distribution, and other resources can be focused more effectively on a smaller group of MassMutual Funds. With respect to the Reorganization of MassMutual Total Return Bond Fund into MassMutual Core Bond Fund, reducing the number of funds in the complex is also intended to enhance the combined fund’s prospects for attracting additional assets by better differentiating the fund for potential shareholders (which may lead to more concentrated selling efforts).

Only one copy of this notice may be delivered to shareholders of a Selling Fund who reside at the same address, unless the Selling Fund has received instructions to the contrary. If you would like to receive an additional copy, please write to MassMutual Funds, c/o Massachusetts Mutual Life Insurance Company (“MassMutual”), 1295

¹ Class Y shares of MassMutual Total Return Bond Fund are not currently available.

State Street, Springfield, Massachusetts 01111-0001, Attention: Investment Management Solutions, or call 1-888-309-3539. Shareholders wishing to receive separate copies of a Selling Fund’s notices in the future, and shareholders sharing an address who wish to receive a single copy if they currently are receiving multiple copies, should also contact the Fund.

NO SHAREHOLDER VOTE WILL BE TAKEN WITH RESPECT TO THE MATTERS DESCRIBED IN THIS IMPORTANT NOTICE OF COMBINED INFORMATION STATEMENT/PROSPECTUS. WE ARE NOT ASKING YOU FOR A PROXY AND YOU ARE REQUESTED NOT TO SEND US A PROXY.

If you have any questions, please contact MML Advisers at 1-888-309-3539.

MassMutual Select Funds

MassMutual Equity Opportunities Fund

MassMutual Total Return Bond Fund

COMBINED INFORMATION STATEMENT/PROSPECTUS

[·], 2025

MML Investment Advisers, LLC (“MML Advisers”) has recommended a series of mutual fund reorganizations as part of an initiative to streamline the mutual funds managed by MML Advisers and its affiliates (the “MassMutual Funds”). As part of this initiative, the board of trustees (the “Board”) of the funds listed above (each, a “Selling Fund” and collectively, the “Selling Funds”) has approved proposals to reorganize each of the Selling Funds into another fund managed by MML Advisers (each, an “Acquiring Fund” and together, the “Acquiring Funds”). The reorganization of each Selling Fund into the Acquiring Fund will enable shareholders of each Selling Fund to invest in a larger, potentially more efficient portfolio while continuing to pursue a substantially similar or comparable investment objective. The Selling Funds and Acquiring Funds are referred to collectively as the “Funds.” The reorganization of the MassMutual Equity Opportunities Fund into the MassMutual Diversified Value Fund is referred to as the “Equity Opportunities Reorganization;” the reorganization of the MassMutual Total Return Bond Fund into the MassMutual Core Bond Fund is referred to as the “Total Return Bond Reorganization” (with the Equity Opportunities Reorganization, each a “Reorganization” and collectively, the “Reorganizations”). No shareholder approval is required to effect the Reorganizations, which are expected to be completed on or about September 15, 2025.

This is a brief overview of the Reorganization of your Selling Fund. Below are answers to some commonly asked questions that are intended to help you understand the reorganization of each of the Selling Funds. The Reorganizations are described in detail in this combined information statement and prospectus (the “Combined Information Statement/Prospectus”). We encourage you to read the full text of the enclosed Combined Information Statement/Prospectus to obtain detailed information with respect to the Reorganization of your Selling Fund. THE FUNDS ARE NOT ASKING YOU FOR A PROXY AND YOU ARE REQUESTED NOT TO SEND A PROXY TO THE FUNDS WITH RESPECT TO THE REORGANIZATIONS.

The enclosed Combined Information Statement/Prospectus provides information about the reorganization of your Selling Fund, and information about the shares that you will receive as a result of the Reorganization.

Although the Combined Information Statement/Prospectus includes information that you should review and keep for future reference, it is not a solicitation of a proxy from you.

A fund reorganization involves one fund transferring its assets to another fund in exchange for shares of the other fund and the other fund assuming the fund’s liabilities. Once the Reorganizations are completed, shareholders of each Selling Fund will hold shares of the Acquiring Fund, and the Selling Fund will then be terminated.

No. In accordance with each Fund’s Declaration of Trust and applicable state and U.S. federal law (including Rule 17a-8 under the Investment Company Act of 1940, as amended (the “1940 Act”)), each Reorganization may be effected without the approval of shareholders of a Fund. Your shares will automatically be converted into shares of the Acquiring Fund on the date of the completion of the Reorganization for your Fund. No certificates for shares will be issued in connection with the Reorganizations. The aggregate net asset value of the Acquiring Fund shares you receive in the Reorganization will be equal to the aggregate net asset value of the shares you own in the applicable Selling Fund immediately prior to such Reorganization. If you sell your shares or are otherwise no longer a shareholder of the Selling Fund as of the closing, this transaction will not impact you.

The Combined Information Statement/Prospectus provides information about the reorganization of the Selling Funds into the Acquiring Funds, as noted in the table below:

The Reorganizations

Each of the Reorganizations involves the transfer of all of the assets of a Selling Fund to, and the assumption of all of the liabilities of the Selling Fund by, an Acquiring Fund, in exchange for a number of shares of equivalent value of the Acquiring Fund.

The respective Board of each Selling Fund and each Acquiring Fund, as applicable, has approved an Agreement and Plan of Reorganization for the Funds (the “Agreement”). The Agreement provides for the transfer of all of the assets of each Selling Fund to its corresponding Acquiring Fund in exchange for the issuance of Acquiring Fund shares and the assumption of all of the Selling Fund’s liabilities by the Acquiring Fund. This transfer will occur following the satisfaction of all conditions to the Reorganization. Following the transfer, the Acquiring Fund shares will be distributed to shareholders of the Selling Fund, and the Selling Fund will be terminated.

As part of the Reorganizations, shareholders of each class of each Selling Fund will receive shares of the same class of the corresponding Acquiring Fund. Each Selling Fund and Acquiring Fund offers the same classes of shares: Class I, Class R5, Service Class, Administrative Class, Class R4, Class A, Class R3, and Class Y².

In each case, you, as a holder of shares of a Selling Fund, will receive shares of the corresponding Acquiring Fund with the same aggregate net asset value as the aggregate net asset value of your Selling Fund shares at the time of the Reorganization. While the aggregate net asset value of your shares will not change as a result of the Reorganization, the number of shares you hold may differ based on each Fund’s net asset value per share.

We encourage you to read the full text of the enclosed Combined Information Statement/Prospectus to obtain a more detailed understanding of the issues relating to each Reorganization.

To reduce costs, the information regarding the Reorganizations have been combined into one Combined Information Statement/Prospectus. Accordingly, both Reorganizations may not be applicable to each shareholder.

MML Advisers, the Selling Funds’ investment adviser, has recommended each Reorganization because it believes that the Reorganization is advisable and in the best interest of the Selling Fund and its shareholders, on balance in light of all relevant factors. MML Advisers believes that the Selling Funds are too small to be economically viable and have limited prospects to grow to sufficient size in the near term. MML Advisers believes the Reorganizations will allow shareholders of both the Selling Funds and the Acquiring Funds to benefit from economies of scale that the combination might provide over time. Following each Reorganization, MML Advisers will continue to serve as the investment adviser to the Acquiring Funds, and each Acquiring Fund’s existing subadviser, sub-subadviser (if any), and portfolio management team are expected to remain

²      Class Y shares of the MassMutual Total Return Bond Fund are not currently available.

responsible for the Acquiring Fund. As noted below, the Reorganization has been structured such that shareholders of each Selling Fund will experience the same or lower total net operating expenses as a result of the Reorganization. The Board of the Selling Funds has carefully reviewed the terms of each Reorganization and determined to approve each Reorganization.

Yes. Each Selling Fund and its corresponding Acquiring Fund have substantially similar or comparable investment objectives; identical fundamental investment restrictions; substantially similar or comparable principal investment strategies; and comparable principal risks. Please see the “Comparison of Investment Objectives,” “Comparison of Principal Investment Strategies,” and “Comparison of Principal Risks” sub-sections of each respective Synopsis of the Reorganization section below, as well as Appendix A, which compares the investment policies for the Selling Funds and the Acquiring Funds, for more detail.

Yes. The portfolio managers of each Acquiring Fund are different than the portfolio managers of the corresponding Selling Fund. The portfolio managers of each Acquiring Fund are expected to continue to manage such Acquiring Fund following the Reorganizations. MML Advisers is the investment adviser of each Selling Fund and each Acquiring Fund, and will continue to serve as investment adviser to the Acquiring Funds following the Reorganizations, and each Acquiring Fund’s subadviser and sub-subadviser, if any, are likewise expected to remain responsible for the Acquiring Fund.

No. Account-level features and options such as dividend distributions, dividend diversification, automatic investment plans, systematic withdrawals, and dollar cost averaging currently set up with your Selling Fund for your Selling Fund account will automatically carry over from accounts in each Selling Fund to accounts in the Acquiring Fund. If you purchase shares through a broker-dealer or other financial intermediary, please contact your financial intermediary for additional details.

Reorganization costs will be allocated among the Funds as described in the Combined Information Statement/Prospectus.

The following paragraph applies only to the Equity Opportunities Reorganization and the Funds and expenses related thereto. With respect to the Equity Opportunities Reorganization, the relevant Selling Fund is expected to bear the direct merger costs, legal fees, audit and tax fees, Form N-14 printing and mailing costs, as well as similar expenses incurred in connection with the consummation of the Equity Opportunities Reorganization and transaction costs (if any) associated with repositioning the Selling Fund prior to such Reorganization. The relevant Acquiring Fund will bear a one-time cost for administratively processing the Reorganization.

The following paragraph applies only to the Total Return Bond Reorganization and the Funds and expenses related thereto. With respect to the Total Return Bond Reorganization except for a one-time cost for administratively processing the Reorganization, which will be borne by the Acquiring Fund, all expenses incurred by the relevant Selling Fund and Acquiring Fund in connection with or arising out of the transactions contemplated by the Agreement and Plan of Reorganization will be borne by MML Advisers (other than any brokerage or other costs relating to transactions in portfolio securities of the relevant Funds, which are expected to be immaterial).

Repositioning costs for each Reorganization are discussed in the “Comparison of Fees and Expenses” sub-section of each respective Synopsis of the Reorganization section below.

Each Reorganization is expected to qualify as a tax-free reorganization for U.S. federal income tax purposes assuming certain conditions are satisfied. Although each Reorganization is expected to be tax-free, i.e., no gains or losses are expected to be recognized by any of the Funds or their shareholders as a direct result of the Reorganizations, fund mergers still have tax consequences, as a fund merger may affect how and when shareholders are taxed after a merger. The tax consequences of the Reorganizations are described in more detail in the section of the Combined Information Statement/Prospectus entitled “ADDITIONAL INFORMATION ABOUT EACH REORGANIZATION - Tax Status of the Reorganizations.” At any time prior to the consummation of the Reorganization, a shareholder may redeem shares, which will generally result in recognition of gain or loss to such shareholder for U.S. federal income tax purposes.

It is expected that, following the Reorganizations, the gross expenses of each Acquiring Fund will be the same as or lower than the gross expenses of the corresponding Selling Fund, and the net expenses borne by Selling Fund shareholders as shareholders of the Acquiring Fund will be the same as or lower than the expenses they currently bear, as described in detail in the “Comparison of Fees and Expenses” sub-section of each respective Synopsis of the Reorganization section below.

Each Reorganization is expected to close on or around September 15, 2025.

If you have questions about any of the Reorganizations described in the Combined Information Statement/Prospectus, please call MML Advisers at 1-888-309-3539. Shareholders of a Selling Fund for which a Reorganization is effected within 60 days following the completion of its fiscal year or half year may request a copy of the Selling Funds’ final report to shareholders for that period by contacting their financial intermediary or by calling 1-888-309-3539.

[•], 2025

Dear Shareholder,

As President of the Selling Funds listed below, I am writing to provide important information about reorganizations that will affect your investment in one or more Selling Funds. As previously communicated in a supplement to your Selling Fund’s prospectus, MML Investment Advisers, LLC (“MML Advisers”), the Selling Funds’ investment adviser, proposed to the board of trustees of the Selling Funds (the “Board”) the reorganization of certain funds managed by MML Advisers (each, a “Reorganization” and collectively, the “Reorganizations”), and the Board unanimously approved the Reorganizations.

The enclosed Combined Information Statement/Prospectus provides information about the Reorganizations of the Selling Funds into other corresponding funds (each, an “Acquiring Fund” and together, the “Acquiring Funds”) managed by MML Advisers. Under the Agreement and Plan of Reorganization, each Selling Fund will transfer that portion of its assets attributable to each class of its shares (in aggregate, all of its assets) to the corresponding Acquiring Fund, as indicated below, in exchange for shares of the same class of shares of the Acquiring Fund and the assumption by the Acquiring Fund of all the liabilities of the Selling Fund. Each Reorganization is expected to close on or about September 15, 2025.

The table below shows each Selling Fund and the corresponding Acquiring Fund for each Reorganization:

The Reorganization of each Selling Fund into the Acquiring Fund will enable shareholders of each Selling Fund to invest in a larger, potentially more efficient portfolio while continuing to pursue a substantially similar or comparable investment objective. The Reorganizations are part of a larger effort intended, among other things, to streamline the MassMutual Funds by reducing the number of funds in the MassMutual Fund complex so that management, distribution, and other resources can be focused more effectively on a smaller group of MassMutual Funds. With respect to the Reorganization of MassMutual Total Return Bond Fund into MassMutual Core Bond Fund, reducing the number of funds in the complex is also intended to enhance the combined fund’s prospects for attracting additional assets by better differentiating the fund for potential shareholders (which may lead to more concentrated selling efforts).

NO ACTION ON YOUR PART IS REQUIRED TO EFFECT A REORGANIZATION. Your shares will automatically be converted into shares of the Acquiring Fund on the date of the completion of the Reorganization for your fund. We are not asking you for a proxy and you are requested not to send us a proxy.

Please carefully read the enclosed Combined Information Statement/Prospectus, as it discusses the Reorganizations in more detail. If you sell your shares or are otherwise no longer a shareholder of the Selling Fund as of the closing date, this transaction will not impact you. If you have questions, please call MML Advisers at 1-888-309-3539.

The information contained in this Combined Information Statement/Prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Combined Information Statement/Prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION

DATED June 5, 2025

COMBINED INFORMATION STATEMENT/PROSPECTUS

Dated [·], 2025

RELATING TO THE ACQUISITION OF THE ASSETS OF

MassMutual Equity Opportunities Fund

MassMutual Total Return Bond Fund

BY AND IN EXCHANGE FOR SHARES OF

MassMutual Diversified Value Fund

MassMutual Core Bond Fund

1295 State Street,

Springfield, MA 01111-0001

Important Notice Regarding the Availability of this Combined Information Statement/Prospectus:

This document (the “Combined Information Statement/Prospectus”) is an information statement for each Selling Fund (as defined below) and a prospectus for each Acquiring Fund (as defined below). The address of each Selling Fund and Acquiring Fund is 1295 State Street, Springfield, MA 01111-0001. The telephone number for each Selling Fund and Acquiring Fund is 1-888-309-3539. This Combined Information Statement/Prospectus was first mailed to shareholders of each Selling Fund beginning on or about [•], 2025. This Combined Information Statement/Prospectus contains information you should know about the reorganizations (each, a “Reorganization” and collectively, the “Reorganizations”), with respect to your Selling Fund, as indicated below. You should read this document carefully and retain it for future reference.

NO SHAREHOLDER VOTE WILL BE TAKEN WITH RESPECT TO THE MATTERS DESCRIBED IN THIS COMBINED INFORMATION STATEMENT/PROSPECTUS. WE ARE NOT ASKING YOU FOR A PROXY AND YOU ARE REQUESTED NOT TO SEND US A PROXY. In accordance with each Fund’s Declaration of Trust and applicable state and U.S. federal law (including Rule 17a-8 under the Investment Company Act of 1940, as amended (the “1940 Act”)), each Reorganization may be effected without the approval of shareholders of a Fund.

Each of the Funds is a registered open-end management investment company (or a series thereof).

Where to Get More Information

The statement of additional information relating to the proposed Reorganizations, dated [•], 2025 (the “Reorganization SAI”) and the other documents identified below have been filed with the Securities and Exchange Commission (the “SEC”) and are incorporated into this Combined Information Statement/Prospectus by reference: MassMutual Select Funds (SEC file nos. 811-08274 and 033-73824)

unaudited financial statements included in the Form N-CSR of each Selling Fund for the period ended March 31, 2025.

For a free copy of any of the documents listed above and/or to ask questions about this Combined Information Statement/Prospectus, please write to MassMutual Funds, c/o Massachusetts Mutual Life Insurance Company, 1295 State Street, Springfield, Massachusetts 01111-0001, Attention: Investment Management Solutions, or call 1-888-309-3539.

Each of the Funds is subject to the information requirements of the Securities Exchange Act of 1934, as amended, and the 1940 Act, and files reports, proxy materials, and other information with the SEC. These reports, proxy materials, and other information can be inspected and copied at the Public Reference Room maintained by the SEC. Copies may be obtained, after paying a duplicating fee, by electronic request at publicinfo@sec.gov, or by writing to the Public Reference Branch of the SEC Office of Consumer Affairs and Information Services, 100 F Street, N.E., Washington, D.C. 20549-0102. In addition, copies of these documents may be viewed online or downloaded from the SEC’s website at www.sec.gov.

Please note that investments in the Funds are not bank deposits, are not federally insured, are not guaranteed by any bank or government agency, and may lose value. There is no assurance that any Fund will achieve its investment objectives.

THE SEC HAS NOT APPROVED OR DISAPPROVED THESE SECURITIES OR PASSED UPON THE ADEQUACY OF THIS COMBINED INFORMATION STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

TABLE OF CONTENTS

SUMMARY

The following is a summary. This summary is not intended to be a complete statement of all material features of the proposed Reorganization and is qualified in its entirety by reference to the full text of this Combined Information Statement/Prospectus, the Agreement and Plan of Reorganization (the “Agreement”), and the other documents referred to herein. You should carefully read the entire Combined Information Statement/Prospectus and the appendices, as they contain details that are not included in this summary.

Reorganizations

The Agreement, which provides for the Reorganization of each Selling Fund into the corresponding Acquiring Fund, was considered and approved (i) by each Acquiring Trust’s Board, including the Trustees who are not “interested persons” (as defined in the 1940 Act) (the “Independent Trustees”) of the Acquiring Funds, at a meeting held on March 18-19, 2025 and (ii) by the Selling Trust’s Board, including the Independent Trustees of the Selling Funds, at a meeting held on March 18-19, 2025. As a result of the Reorganizations:

The completion of each Reorganization is subject to certain conditions described in the Agreement. For the reasons set forth below in “ADDITIONAL INFORMATION ABOUT EACH REORGANIZATION - Reasons for the Reorganizations and Board Deliberations,” the Selling Trust’s Board, including the Independent Trustees, have concluded that (i) participation in each Reorganization is advisable and in the best interest of the relevant Selling Fund and its shareholders, on balance in light of all relevant factors; and (ii) the interests of the existing shareholders of each Selling Fund will not be diluted as a result of its Reorganization.

Costs of the Reorganization

Reorganization costs will be allocated among the Funds, as described in this Combined Information Statement/Prospectus and in the Agreement.

The following paragraph applies only to the Equity Opportunities Reorganization and the Funds and expenses related thereto. With respect to the Equity Opportunities Reorganization, the relevant Selling Fund is expected to bear

the direct merger costs, legal fees, audit and tax fees, Form N-14 printing and mailing costs, as well as similar expenses incurred in connection with the consummation of the Equity Opportunities Reorganization and transaction costs (if any) associated with repositioning the Selling Fund prior to such Reorganization. The relevant Acquiring Fund will bear a one-time cost for administratively processing the Reorganization.

The following paragraph applies only to the Total Return Bond Reorganization and the Funds and expenses related thereto. With respect to the Total Return Bond Reorganization, except for a one-time cost for administratively processing the Reorganization, which will be borne by the Acquiring Fund, all expenses incurred by the relevant Selling Fund and Acquiring Fund in connection with or arising out of the transactions contemplated by the Agreement and Plan of Reorganization will be borne by MML Investment Advisers, LLC (“MML Advisers”) (other than any brokerage or other costs relating to transactions in portfolio securities of the relevant Funds, which are expected to be immaterial).

U.S. Federal Income Tax Consequences

Each Reorganization is expected to qualify as a tax-free reorganization for U.S. federal income tax purposes assuming certain conditions are satisfied and will not take place unless the Selling Fund and the corresponding Acquiring Fund receive a satisfactory opinion of tax counsel substantially to the effect that the Reorganization will qualify as a tax-free reorganization, as described in more detail in the section entitled “ADDITIONAL INFORMATION ABOUT EACH REORGANIZATION-Tax Status of the Reorganizations.” Although each Reorganization is expected to be tax-free, i.e., no gains or losses are expected to be recognized by any of the Funds or their shareholders as a direct result of the Reorganizations, fund mergers still have tax consequences, as a fund merger may affect how and when shareholders are taxed after a merger. At any time prior to a Reorganization, a shareholder may redeem shares of a Selling Fund. Any such redemption would likely result in the recognition of gain or loss by the shareholder for U.S. federal income tax purposes. If a shareholder holds Selling Fund shares in a non-taxable account, distributions and redemption proceeds with respect to those shares will not be taxable to the shareholder if those amounts remain in the non-taxable account but may be subject to U.S. federal income taxes upon a later withdrawal of monies from such account.

The Selling Fund shareholders’ aggregate tax basis in the Merger Shares is expected to carry over from the shareholders’ Selling Fund shares, and the Selling Fund shareholders’ holding period in the Merger Shares is expected to include the shareholders’ holding period in the Selling Fund shares.

For more information about the U.S. federal income tax consequences of the Reorganizations, see the section entitled “ADDITIONAL INFORMATION ABOUT EACH REORGANIZATION-Tax Status of the Reorganizations.”

Investment Objectives, Policies, Principal Investment Strategies, and Principal Risks

The investment objectives, policies, principal investment strategies, and principal risks of the Selling Fund of which you are a record owner can be found in the Selling Fund prospectus and statement of additional information. The investment objectives, policies, principal investment strategies, and principal risks of the corresponding Acquiring Fund can be found in this Combined Information Statement/Prospectus.

Investment Objectives

Each Selling Fund and its corresponding Acquiring Fund have substantially similar or comparable investment objectives, as discussed in more detail below.

Investment Policies

The 1940 Act requires, and each Selling Fund and Acquiring Fund has, fundamental investment policies relating to investing in commodities, concentration in particular industries, making loans, investing in real estate, acting as an underwriter, and issuing senior securities and borrowing money. These policies may not be changed without shareholder approval. Each Selling Fund and each Acquiring Fund have also adopted certain non-fundamental policies that may be changed without shareholder approval. Each Selling Fund and Acquiring Fund have identical fundamental investment policies. MassMutual Equity Opportunities Fund and MassMutual Diversified Value Fund also have identical non-fundamental investment policies. MassMutual Core Bond Fund and MassMutual Total Return Bond Fund have comparable non-fundamental investment policies. A comparison of the investment policies of each Selling Fund and its corresponding Acquiring Fund appears in Appendix A.

Investment Strategies

Each Selling Fund and its corresponding Acquiring Fund have either substantially similar or comparable principal investment strategies. For additional information regarding the principal investment strategies of the Selling Funds and the Acquiring Funds, please see the “Comparison of Principal Investment Strategies” sub-section of each respective Synopsis of the Reorganization section below, as well Appendix C.

Principal Risks

Each Selling Fund and its corresponding Acquiring Fund have comparable principal risks. For additional information regarding the principal risks of the Selling Funds and the Acquiring Funds, please see the “Comparison of Principal Risks” sub-section of each respective Synopsis of the Reorganization section below, as well as Appendix B, which includes the full text of the principal risks of the Acquiring Funds.

Fees and Expenses

The Reorganizations have been structured such that shareholders of each Selling Fund will not experience an increase in effective management fee rate, total expense ratio, or Rule 12b-1 fee rate as a result of the Reorganization. It is expected that, following the Reorganizations, the gross expenses of each Acquiring Fund will be the same as or lower than the gross expenses of the corresponding Selling Fund, and the net expenses borne by Selling Fund shareholders as shareholders of the Acquiring Fund will be the same as or lower than the expenses they currently bear, as described in detail in the “Comparison of Fees and Expenses” sub-section of each respective Synopsis of Reorganization section below.

Performance

Performance information for each Selling Fund and Acquiring Fund is located under the “Performance” sub-section of each respective Synopsis of the Reorganization section below.

Management of the Funds

MML Advisers, a wholly-owned subsidiary of MassMutual, serves as the investment adviser for each of the Selling Funds and Acquiring Funds and will continue to serve as the investment adviser to the Acquiring Funds following the Reorganizations.

It is anticipated that each of the subadviser and sub-subadviser, as applicable, and the portfolio managers that manage each Acquiring Fund will, upon completion of the Reorganizations, continue to manage the same Acquiring Fund. Additional information concerning the portfolio managers of each of the Acquiring Funds can be found in the “Management” sub-section of each respective Synopsis of Reorganization section below and in Appendix D.

T. Rowe Price Associates, Inc. (“T. Rowe Price”) and Wellington Management Company LLP (“Wellington Management”) serve as the subadvisers for MassMutual Equity Opportunities Fund. Brandywine Global Investment Management, LLC (“Brandywine Global”) serves as the subadviser for MassMutual Diversified Value Fund and will serve as the subadviser to the combined fund.

Metropolitan West Asset Management, LLC (“MetWest”) serves as the subadviser for MassMutual Total Return Bond Fund. Barings LLC (“Barings”) serves as the subadviser for MassMutual Core Bond Fund, and Baring International Investment Limited (“BIIL”) serves as the sub-subadviser for MassMutual Core Bond Fund and will serve as the subadviser and sub-subadviser to the combined fund.

Distribution Arrangements

Shares of each Fund are sold on a continuous basis by MML Distributors, LLC (the “Distributor”), 1295 State Street, Springfield, Massachusetts 01111-0001, the distributor for each Fund. Class I, Class Y, Class R5, Class R4, Class R3, Service Class, and Administrative Class shares of the Funds are sold at net asset value per share, with no sales charges. None of Class I, Class Y, Class R5, Service Class, and Administrative Class shares of the Funds pay distribution and service (12b-1) fees. Class R4, Class A, and Class R3 shares of the Funds pay distribution and service (12b-1) fees, as indicated in the “Comparison of Fees and Expenses” sub-section of each respective Synopsis of

Reorganization section below. The Distributor is expected to continue providing substantially the same services for the Acquiring Funds after completion of the Reorganizations as it currently provides to the Acquiring Funds and Selling Funds. You will not be charged any sales charges, commissions, or transactions fees in connection with the Reorganizations.

Each Fund’s shares are continuously distributed by the Distributor pursuant to a Principal Underwriter Agreement with the Selling Trust and Acquiring Trusts, as applicable, as amended (the “Distribution Agreement”). The Distributor pays commissions to its selling dealers as well as the costs of printing and mailing prospectuses to potential investors and of any advertising incurred by it in connection with distribution of shares of the Funds. The Distributor is a wholly-owned subsidiary of MassMutual.

The Distributor has agreed to use reasonable efforts to sell shares of the Funds but has not agreed to sell any specific number of shares of the Funds. The Distributor’s compensation for serving as such is the amounts received by it from time to time under the Funds’ Amended and Restated Rule 12b-1 plan. In addition, the Distributor receives any front-end sales charges or contingent deferred sales charges (“CDSCs”) imposed on the sales of Class A shares of the Funds. The Distributor is expected to provide substantially the same services for the combined funds after the Reorganizations as it currently provides to the Selling Funds and Acquiring Funds.

Purchase and Sale of Fund Shares

In general, shareholders may purchase or redeem shares of a Fund on days when the New York Stock Exchange (“NYSE”) is open for business.

The Funds operate under substantially identical purchase procedures. Shares of each Fund are generally available through various financial intermediaries, such as retirement plan recordkeepers, broker-dealers, financial institutions, and insurance companies, and to other institutional investors and individual retirement accounts. Shares of each Fund are redeemable on any business day by written request, telephone, or internet (available to certain customers).

For additional information about the purchase and redemption policies of the Acquiring Funds, see “Buying, Redeeming, and Exchanging Shares” in Appendix E.

Exchange Privileges and Conversion Rights

Generally, shareholders of a Selling Fund or an Acquiring Fund may exchange shares of the Fund for the same class of shares of another MassMutual Fund, if they satisfy eligibility requirements for that fund. Any share class of a Selling Fund or an Acquiring Fund may be exchanged for Class R5 shares of the MassMutual U.S. Government Money Market Fund. An exchange is treated as a sale of shares in one MassMutual Fund and a purchase of shares in another MassMutual Fund at the net asset value next determined after the exchange request is received and accepted by the transfer agent, MML Advisers, a broker-dealer, or another intermediary authorized for this purpose. A shareholder can only exchange into shares of another MassMutual Fund if such shareholder meets any qualification requirements of the MassMutual Fund into which the shareholder seeks to exchange.

Exchange and conversion rights may be subject to further restrictions and limitations, as further described in the respective Fund’s prospectus, and are subject to change at any time. For additional information on the exchange rights of the Acquiring Funds, see “Buying, Redeeming, and Exchanging Shares - Exchanges” in Appendix E.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase any of the Funds through a broker-dealer or other financial intermediary, the intermediary may receive a one-time or continuing payments from that Fund, MML Advisers, or their affiliates, or others for the sale of Fund shares or continuing shareholder services provided by the intermediary. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary to recommend the Fund over another investment. You should contact your intermediary to obtain more information about the compensation it may receive in connection with your investment.

Tax Information

Each Selling Fund and each Acquiring Fund has elected or intends to elect to be treated, and intends to qualify and be treated each year, as a regulated investment company (a “RIC”) under Subchapter M of the Internal Revenue Code of 1986, as amended (the “Code”), for U.S. federal income tax purposes and expects to distribute net investment income and net realized capital gains, if any, to shareholders at least annually. These distributions are taxable as ordinary income or capital gain to U.S. shareholders that are neither exempt from U.S. income tax nor investing through a tax-advantaged account such as a tax-qualified retirement plan.

SYNOPSIS OF REORGANIZATION #1 - MASSMUTUAL EQUITY OPPORTUNITIES FUND INTO MASSMUTUAL DIVERSIFIED VALUE FUND

Comparison of Investment Objectives

Analysis

The investment objectives of MassMutual Equity Opportunities Fund and MassMutual Diversified Value Fund (together, the “Funds”) are substantially similar. Both Funds seek to achieve growth of capital over the long term. MassMutual Diversified Value Fund also focuses on growth of income. Additionally, MassMutual Diversified Value Fund’s objective is to invest primarily in a diversified portfolio of equity securities of larger, well-established companies. Each Fund’s investment objective and strategies are non-fundamental and may be changed by the Funds’ Board without shareholder approval. There can be no assurance that either Fund will be able to achieve its investment objective.

Comparison of Principal Investment Strategies

Principal Investment Strategies - MassMutual Equity Opportunities Fund

The Fund invests primarily in equity securities of U.S. companies that the Fund’s subadvisers believe are financially sound, valued conservatively by the market, and have improving prospects. The Fund is managed by two subadvisers, T. Rowe Price Associates, Inc. (“T. Rowe Price”) and Wellington Management Company LLP (“Wellington Management”), each being responsible for a portion of the portfolio, although they may manage different amounts of the Fund’s assets. Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stocks, rights, and warrants, of issuers of any size. The Fund typically invests most of its assets in equity securities of U.S. companies, but may invest in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. The Fund generally will not invest more than 30% of its total assets in foreign securities. The Fund may use futures contracts for hedging or investment purposes as a substitute for investing directly in securities. Use of derivatives by the Fund may create investment leverage. The Fund may at times have significant exposure to one or more industries or sectors. The Fund may hold a portion of its assets in cash or cash equivalents.

T. Rowe Price typically employs a “value” approach in selecting investments, using internal research to identify companies that appear to be undervalued by various measures and may be temporarily out of favor but have good prospects for capital appreciation and dividend growth. T. Rowe Price generally looks for companies with one or more of the following: an established operating history; above-average dividend yield and low price/earnings ratio relative to the Russell 1000® Value Index; a sound balance sheet and other positive financial characteristics; and low stock price relative to T. Rowe Price’s view of the company’s underlying value as measured by assets, cash flow, or business franchises. T. Rowe Price generally seeks investments in large-capitalization companies and the yield of the portion of the Fund managed by T. Rowe Price is expected to normally exceed the yield of the Russell 1000 Value Index. T. Rowe Price may sell assets for a variety of reasons, including in response to a change in the original investment considerations or to limit losses, adjust the characteristics of the overall portfolio, or redeploy assets into different opportunities.

Wellington Management seeks long-term total returns in excess of the broad market by investing in a select number of high quality, reasonably-valued companies that have demonstrated the willingness to return value to shareholders. The investment process stresses security selection based on bottom-up fundamental research to identify attractively valued stocks that have the potential for significant longer-term rewards. Wellington Management’s investment philosophy is based on the premise that investing in high quality companies with superior prospects for dividend growth, and the fundamental strength to support that growth in the future, can provide superior long-term

returns. Wellington Management typically sells a security when it achieves its price target or when it no longer exhibits superior upside return versus downside risk.

In pursuing the Fund’s investment objective, each of T. Rowe Price and Wellington Management has the discretion to purchase some securities that do not meet its normal investment criteria described above, when it believes there is an opportunity for substantial appreciation (such as, for example, T. Rowe Price or Wellington Management believes a security could increase in value as a result of a change in management, an extraordinary corporate event, a new product introduction or innovation, or a favorable competitive development).Principal Investment Strategies - MassMutual Diversified Value Fund

The Fund invests primarily in stocks of companies that the Fund’s subadviser, Brandywine Global Investment Management, LLC (“Brandywine Global”), believes are undervalued in the marketplace. While the Fund does not limit its investments to issuers in a particular capitalization range, Brandywine Global currently focuses on securities of larger size companies. The Fund normally invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in stocks, securities convertible into stocks, and other securities, such as warrants and stock rights, whose value is based on stock prices. The Fund typically invests most of its assets in securities of U.S. companies, but may invest up to 25% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. The Fund may use futures contracts for hedging or investment purposes as a substitute for investing directly in securities. Use of derivatives by the Fund may create investment leverage. The Fund may at times have significant exposure to one or more industries or sectors. The Fund may hold a portion of its assets in cash or cash equivalents.

Brandywine Global employs a bottom-up, value-based investment approach in selecting securities for the Fund. Brandywine Global invests in securities that meet its value criteria, primarily, price-to-earnings, price-to-book, price momentum, and share change and quality, based on both quantitative and fundamental analysis. Brandywine Global expects to hold approximately 175 – 250 stocks under normal market conditions.

Brandywine Global invests in securities of companies that meet its value criteria based on both quantitative and fundamental analysis. Brandywine Global’s investment process begins with a valuation screen that identifies large-capitalization stocks with favorable financial ratios. A quantitative deselection process is then applied to eliminate equities that have poor price momentum or high share issuance. Finally Brandywine Global performs a thorough fundamental analysis which seeks to identify and eliminate (de-select) companies with deteriorating fundamentals, anticipated earnings declines, or material write-offs. Brandywine Global may also consider additional factors in its selection process.

Brandywine Global typically sells a security of a company when Brandywine Global believes it is no longer a large-capitalization value company, if the company’s fundamentals deteriorate, when an investment opportunity arises that Brandywine Global believes is more compelling, or in order to realize gains or limit potential losses. However, Brandywine Global may retain securities of companies that no longer meet its initial purchase criteria.

Comparison of Principal Investment Strategies

The Funds have substantially similar principal investment strategies. The main differences between the Funds’ principal investment strategies is the foreign exposure limit and the number of securities each Fund is expected to hold under normal market conditions. MassMutual Equity Opportunities Fund may invest up to 30% of total assets in securities of foreign issuers and ADRs, and MassMutual Diversified Value Fund permits up to 25%. The MassMutual Equity Opportunities Fund’s exposure to foreign issuers and ADRs as of March 31, 2025 was 6.54% of total assets, and the MassMutual Diversified Value Fund’s exposure to foreign issuers and ADRs as of March 31, 2025 was 1.53% of total assets. Under normal market conditions, the MassMutual Diversified Value Fund expects to hold approximately 175 – 250 stocks. The MassMutual Equity Opportunities Fund does not state an expected number of holdings in its principal investment strategies. As of March 31, 2025, the MassMutual Equity Opportunities Fund held 63 equity securities, and the MassMutual Diversified Value Fund held 222 equity securities.

Under normal market conditions, both Funds invest in equity securities that each Fund’s respective subadviser(s) believe to be undervalued, and, under normal market conditions, each Fund invests at least 80% of its assets in equity securities of various types, with a focus on companies with large market capitalizations. Each Fund also may invest a portion of its assets into foreign securities and ADRs, including emerging market securities.

MassMutual Equity Opportunities Fund generally will not invest more than 30% of its total assets in foreign securities. MassMutual Diversified Value Fund may invest up to 25% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. Each Fund may use futures contracts for hedging or investment purposes as a substitute for investing directly in securities.

Both Funds may at times have significant exposure to one or more industries or sectors and may hold a portion of their respective assets in cash or cash equivalents. In pursuing MassMutual Equity Opportunities Fund’s investment objective, each of T. Rowe Price and Wellington Management has the discretion to purchase some securities that do not meet its normal investment criteria described above, when it believes there is an opportunity for substantial appreciation. In pursuing MassMutual Diversified Value Fund’s investment objective, Brandywine Global invests in securities of companies that meet its value criteria based on both quantitative and fundamental analysis.

Comparison of Fees and Expenses

The following tables describe the fees and expenses that you may pay if you buy, hold, and sell shares of each of the Funds. You may pay brokerage commissions and other fees to financial intermediaries which are not reflected in the tables and Examples below. For Class A shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in MassMutual Funds. More information about these and other discounts is available in each Fund’s prospectus or from your financial professional. The tables show fees and expenses that the Selling Fund and Acquiring Fund incurred in its most recent fiscal year ended September 30, 2024, as well as pro forma fees and expenses that MML Advisers expects the Acquiring Fund would have incurred during the twelve months ended March 31, 2025, assuming consummation of the Reorganization as of March 31, 2024. In general, a Fund’s annual operating expense ratios will increase as the Fund’s assets decrease and will decrease as the Fund’s assets increase. Accordingly, each Fund’s annual operating expense ratios, if adjusted based on net assets as of the date of this Combined Information Statement/Prospectus, could be higher or lower than those shown in the tables below. Shareholders of the Selling Fund will not pay any sales charges or redemption fees in connection with the Reorganization. The fees and expenses below exclude one-time costs of the Reorganization, which will be borne by the Selling Fund and the Acquiring Fund, as described under the “Costs of the Reorganization” section above and the “Reasons for the Reorganizations and Board Deliberations” section below.

Current and Pro Forma Shareholder Fees

Shareholder Fees (fees paid directly from your investment)

Current and Pro Forma Annual Fund Operating Expenses

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)

Repositioning Costs

As of the date of this Combined Information Statement/Prospectus, MML Advisers expects that the Selling Fund will reposition its portfolio holdings prior to the Reorganization. The repositioning may result in brokerage commissions and other transaction costs which MML Advisers has estimated to be approximately $979,939.37 (representing 83% of the Selling Fund’s net assets as of December 31, 2024). This estimate includes both explicit cost estimates (brokerage commissions and transaction fees) and implicit cost estimates (historical averages of projected market impact costs and bid/ask spreads). These costs will be borne by the Selling Fund and are not included in the Reorganization costs described elsewhere in this Combined Information Statement/Prospectus. These figures are estimates and the Fund’s actual portfolio realignment may differ.

Expense Examples

The Examples are intended to help you compare the costs of investing in shares of the Selling Fund or the Acquiring Fund with the costs of investing in other mutual funds. The Examples assume that (i) you invest $10,000 in each share class of the relevant Fund for the time periods indicated and then redeem all your shares at the end of those periods, (ii) your investment has a 5% return each year, and (iii) the relevant Fund’s operating expenses are exactly as described in the corresponding preceding Annual Fund Operating Expanses table. For Class A shares, the Examples include the front-end sales charge. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

MassMutual Equity Opportunities Fund (Current)

MassMutual Diversified Value Fund (Current)

MassMutual Diversified Value Fund (Pro Forma) (Combined Fund)

Portfolio Turnover

The Selling Fund and Acquiring Fund pay transaction costs, such as commissions, when they buy and sell securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the expense Examples, affect each of the Funds’ performance. During the most recent fiscal year, the Selling Fund’s and Acquiring Fund’s portfolio turnover rates, as a percentage of the average value of each Fund’s portfolio, were as follows:

Comparison of Principal Risks

The principal risks associated with investments in the Acquiring Fund and the Selling Fund are comparable because the Funds have substantially similar investment objectives and investment strategies. The following chart

identifies the principal risks associated with each Fund. As shown in the chart, the Selling Fund is subject to many of the principal risks of the Acquiring Fund. The actual risks of investing in a Fund depends on the securities the Fund holds and on market conditions, both of which will change over time. Each of the principal risks of the Acquiring Fund appears in Appendix B.

The Funds are subject to many of the same principal risks, but differ primarily given that the Selling Fund is subject to the risks associated with investments in preferred stocks and small and mid-cap companies, while the Acquiring Fund does not identify these investment risks as a principal risk. Additionally, the Acquiring Fund, unlike the Selling Fund, is subject to risks associated with use of quantitative models.

Performance

The following bar charts and tables show, respectively:

The following bar charts and tables below provide some indication of the risks of investing in the Acquiring Fund and Selling Fund by showing changes in each Fund’s annual total returns from year to year for the periods indicated and by comparing each Fund’s average annual total returns for different calendar periods with those of a broad-based index.

MassMutual Equity Opportunities Fund

The Selling Fund commenced operations on May 1, 2000. The following bar chart and table provide some indication of the risks of investing in the Selling Fund. The bar chart shows changes in the Selling Fund’s performance from year to year for Class R5 shares. The table shows how the Selling Fund’s average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance and an additional index that MML Advisers believes more closely reflects the market segments in which the Selling Fund invests (Russell 1000® Index). The Selling Fund’s name and investment strategy changed on March 28, 2017. The performance results shown below would not

necessarily have been achieved had the Selling Fund’s current investment strategy been in effect for the entire period for which performance results are presented. Performance for Class Y shares of the Selling Fund for periods prior to its inception date (02/01/23) is based on the performance of Class R5 shares. Performance for Class A shares of the Selling Fund reflects any applicable sales charge. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More up-to-date performance information is available at https://www.massmutual.com/product-performance/mutual-funds or by calling 1-888-309-3539.

Annual Total Returns (for calendar years ended December 31) - Class R5 Shares Before Taxes

Annual Performance

The Selling Fund’s highest/lowest quarterly results during this time period were:

Highest Quarter: 4Q ’22, 13.26%

Lowest Quarter: 1Q ’20, –19.57%

The Selling Fund’s year-to-date total return as of January 1, 2025 - March 31, 2025: 0.59%

Average Annual Total Returns (for periods ended December 31, 2024) Applicable sales charges are reflected

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class R5 only. After-tax returns for other classes will vary.

(1)   Effective July 24, 2024, the S&P 500 Index replaced the Russell 1000 Index as a broad measure of market performance in accordance with new regulatory disclosure requirements. The Selling Fund continues to use the Russell 1000 Index as a supplemental benchmark that MML Advisers believes more closely reflects the market segments in which the Fund invests.

MassMutual Diversified Value Fund

The following bar chart and table provide some indication of the risks of investing in the Acquiring Fund. The bar chart shows changes in the Acquiring Fund’s performance from year to year for Class R5 shares. The table shows how the Acquiring Fund’s average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance and an additional index that MML Advisers believes more closely reflects the market segments in which the Fund invests (Russell 1000 Value Index). Performance for Class Y shares of the Acquiring Fund for periods prior to its inception date (02/01/23) is based on the performance of Class R5 shares. Performance for Class A shares of the Acquiring Fund reflects any applicable sales charge. Past performance (before and after taxes) is not necessarily an indication of how the Acquiring Fund will perform in the future. More up-to-date performance information is available at https://www.massmutual.com/product-performance/mutual-funds or by calling 1-888-309-3539.

Annual Total Returns (for calendar years ended December 31) - Class R5 Shares Before Taxes

Annual Performance

The Acquiring Fund’s highest/lowest quarterly results during this time period were:

Highest Quarter: 4Q ’20, 16.46%

Lowest Quarter: 1Q ’20, –27.50%

The Acquiring Fund’s year-to-date total return as of January 1, 2025 - March 31, 2025: 3.45%

Average Annual Total Returns (for periods ended December 31, 2024) Applicable sales charges are reflected

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class R5 only. After-tax returns for other classes will vary.

(1)   Effective July 24, 2024, the Russell 3000 Index replaced the Russell 1000 Value Index as a broad measure of market performance in accordance with new regulatory disclosure requirements. The Acquiring Fund continues to use the Russell 1000 Value Index as a supplemental benchmark that MML Advisers believes more closely reflects the market segments in which the Fund invests.

Management

Investment Adviser

MML Advisers, a wholly-owned subsidiary of MassMutual, serves as the investment adviser for the Selling Fund and Acquiring Fund. Following the Reorganization, MML Advisers will continue to serve as the Acquiring Fund’s investment adviser, and the existing subadviser and portfolio management team are expected to remain responsible for the Acquiring Fund.

Investment Subadvisers

T. Rowe Price and Wellington Management serve as the subadvisers for the Selling Fund. Brandywine Global serves as the subadviser for the Acquiring Fund and will continue to serve as the Acquiring Fund’s subadviser following the Reorganization.

Portfolio Managers

It is anticipated that each of the portfolio managers that manage the Acquiring Fund will, upon completion of the Reorganization, continue to manage the Acquiring Fund. Additional information regarding the portfolio managers of the Acquiring Fund can be found in Appendix D.

SYNOPSIS OF REORGANIZATION #2 - MASSMUTUAL TOTAL RETURN BOND FUND INTO MASSMUTUAL CORE BOND FUND

Comparison of Investment Objectives

Analysis

The investment objectives of MassMutual Total Return Bond Fund and MassMutual Core Bond Fund (together, the “Funds”) are comparable. Both Funds seek a high rate of total return by investing in fixed-income instruments and securities. The MassMutual Core Bond Fund specifically seeks to achieve a high total rate of return consistent with prudent investment risk and the preservation of capital, and the MassMutual Core Bond Fund invests in investment-grade securities. Each Fund’s investment objective and strategies are non-fundamental and may be changed by each Fund’s Board without shareholder approval. There can be no assurance that either Fund will be able to achieve its investment objective.

Comparison of Principal Investment Strategies

Principal Investment Strategies - MassMutual Total Return Bond Fund

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in a diversified portfolio of investment grade fixed income securities (rated Baa3 or higher by Moody’s, BBB- or higher by Standard & Poor’s, BBB- or higher by Fitch, or A-2 by S&P, P-2 by Moody’s, or F-2 by Fitch for short-term debt obligations, or, if unrated, determined by the Fund’s subadviser, Metropolitan West Asset Management, LLC (“MetWest”), to be of comparable quality). These typically include bonds, notes, collateralized bond obligations, collateralized debt obligations, mortgage-related and asset-backed securities, municipal securities, private placements, and securities subject to legal restrictions on resale pursuant to Rule 144A. These investments may have interest rates that are fixed, variable, or floating. The Fund invests in securities of varying maturities issued by domestic and foreign corporations and governments (and their agencies and instrumentalities). MetWest focuses the Fund’s portfolio holdings in areas of the bond market (based on quality, sector, coupon, or maturity) that the subadviser believes to be relatively undervalued.

The Fund may invest up to 20% of its net assets in below investment grade debt securities (“junk” or “high yield” bonds), including securities in default and bank loans. In the event that a security is downgraded after its purchase by the Fund, the Fund may continue to hold the security if MetWest considers doing so would be consistent with the Fund’s investment objective.

The Fund may invest up to 25% of its total assets in foreign securities that are denominated in U.S. dollars. The Fund may also invest up to 15% of its total assets in foreign securities that are not denominated in U.S. dollars and up to 10% of its total assets in emerging market foreign securities.

The Fund may but will not necessarily engage in foreign currency forward transactions to take long or short positions in foreign currencies in order to seek to enhance the Fund’s investment return or to seek to hedge or to attempt to protect against adverse changes in currency exchange rates. In pursuing its investment objective, the Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, including options, futures contracts, and swap contracts for hedging or investment purposes as a substitute for investing directly in securities or to adjust various portfolio characteristics, including the duration (interest rate volatility) of the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage.

The Fund may purchase and sell securities on a when-issued, delayed delivery, or forward commitment basis. The Fund may normally short sell up to 25% of the value of its total assets for hedging or investment purposes.

The Fund may also invest in money market securities, including commercial paper. The Fund may enter into repurchase agreement transactions. The Fund may at times have significant exposure to one or more industries or sectors. The Fund may hold a portion of its assets in cash or cash equivalents. The Fund may enter into dollar roll or reverse repurchase agreement transactions.

MetWest intends for the Fund’s portfolio duration to be between two to eight years. The dollar-weighted average maturity of the Fund’s portfolio is expected to range from two to fifteen years. Duration measures the price sensitivity of a bond to changes in interest rates.

Duration is the dollar weighted average time to maturity of a bond utilizing the present value of all future cash flows.

MetWest employs a value-oriented fixed income management philosophy with a goal of consistently outperforming the portfolio benchmark while maintaining volatility similar to the benchmark. The investment process is predicated on a long-term economic outlook, which is determined by the investment team on a quarterly basis and is reviewed constantly. Investments are characterized by diversification among the sectors of the fixed income marketplace. The investment management team seeks to achieve the desired outperformance through the measured and disciplined application of five fixed income management strategies which include duration management, yield curve positioning, sector allocation, security selection, and opportunistic execution.

The first three strategies are top-down in orientation and start with a decision of where within the plus-or-minus one year range around the benchmark the duration should be established. Then comes a determination of how the overall average duration is to be effected – with a concentration of intermediate maturity issues or a combination of long- and short-term issues. The relative value decision regarding where to overweight/underweight sectors, including governments, agencies, corporates, mortgages, or asset-backed securities, is dependent on the current market environment. Bottom-up security selection involves the day-to-day fundamental analysis of available bond market opportunities, while execution is characterized by the aggressive and informed negotiation of the prices at which transactions take place.

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Principal Investment Strategies - MassMutual Core Bond Fund

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in investment grade fixed income securities (rated Baa3 or higher by Moody’s, BBB- or higher by Standard & Poor’s or the equivalent by any other nationally recognized statistical rating organization, or, if unrated, determined to be of comparable quality by the Fund’s subadviser, Barings LLC (“Barings”), or sub-subadviser, Baring International Investment Limited (“BIIL”)). These typically include U.S. dollar-denominated corporate obligations, securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities, U.S. and foreign issuer dollar-denominated bonds including, but not limited to, corporate obligations, government and agency issues, private placement bonds, securities subject to resale pursuant to Rule 144A, and mortgage-backed and other asset-backed securities, including collateralized bond and loan obligations. In the event that a security is downgraded after its purchase by the Fund, the Fund may continue to hold the security if Barings or BIIL considers that doing so would be consistent with the Fund’s investment objective.

In pursuing its investment objective, the Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, including, but not limited to, futures contracts and forward contracts, including derivatives thereof (for hedging purposes, to adjust various portfolio characteristics, including the duration (interest rate volatility) of the Fund’s portfolio, or as a substitute for direct investments); interest rate swaps (for hedging purposes or as a substitute for direct investments); total return swaps (for hedging purposes or to gain exposure to securities or markets in which it might not be able to invest directly); and credit default swaps (for hedging purposes or as a substitute for direct investments). The Fund may invest in common stocks, exchange-traded funds (“ETFs”), or other equity securities and derivatives thereof for hedging purposes or to enhance total return. Use of derivatives by the Fund may create investment leverage.

The Fund may invest in money market securities, including commercial paper. The Fund may enter into repurchase agreement transactions. The Fund may at times have significant exposure to one or more industries or sectors. The Fund may hold a portion of its assets in cash or cash equivalents. The Fund may purchase and sell securities on a when-issued, delayed delivery, to-be-announced, or forward commitment basis, and may enter into dollar roll or reverse repurchase agreement transactions.

The Fund may invest in other investment companies, including investment companies that are advised by the Fund’s investment adviser, subadviser, sub-subadviser, or its affiliates, or by unaffiliated parties.

Barings or BIIL intends for the Fund’s portfolio dollar-weighted average duration generally to match (within 10%) the average duration of the Bloomberg U.S. Aggregate Bond Index (as of December 31, 2024, the average duration of the Index was 6.02 years). Duration measures the price sensitivity of a bond to changes in interest rates. Duration is the dollar weighted average time to maturity of a bond utilizing the present value of all future cash flows.

Barings or BIIL selects the Fund’s investments based on its analysis of opportunities and risks of various fixed income securities and market sectors. Currently, Barings or BIIL may consider the following factors (which may change over time and in particular cases): the perceived potential for high income offered by different types of corporate and government obligations (including mortgage-backed and other asset-backed securities); diversification among industries and issuers, credit ratings, and sectors; and the relative values offered by different securities.

Barings or BIIL may choose to sell securities with deteriorating credit or limited upside potential compared to other securities.

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Comparison of Principal Investment Strategies

The Funds have comparable principal investment strategies, including that both Funds invest primarily in investment grade fixed income securities. The Funds’ strategies have two notable differences:

In light of these differences in the Funds’ principal investment strategies, it is expected that the MassMutual Core Bond Fund will generally present less credit risk and interest rate risk to shareholders than the MassMutual Total Return Bond Fund.

Under normal market conditions, both Funds invest at least 80% of their assets in fixed-income securities. MassMutual Total Return Bond Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in a diversified portfolio of investment grade fixed income securities (rated Baa3 or higher by Moody’s, BBB- or higher by Standard & Poor’s, BBB- or higher by Fitch, or A-2 by S&P, P-2 by Moody’s, or F-2 by Fitch for short-term debt obligations, or, if unrated, determined by MetWest to be of comparable quality), but may invest up to 20% of its net assets in below investment grade debt securities, including securities in default and bank loans. MassMutual Core Bond Fund invests at least 80% of its net assets in investment-grade securities (rated Baa3 or higher by Moody’s, BBB- or higher by Standard & Poor’s or the equivalent by any other nationally recognized statistical rating organization, or, if unrated, determined to be of comparable quality by Barings or BIIL).

MassMutual Total Return Bond Fund’s investments typically include bonds, notes, collateralized bond obligations, collateralized debt obligations, mortgage-related and asset-backed securities, municipal securities, private placements, and securities subject to legal restrictions on resale pursuant to Rule 144A. These investments may have interest rates that are fixed, variable, or floating. The MassMutual Total Return Bond Fund invests in securities of varying maturities issued by domestic and foreign corporations and governments (and their agencies and instrumentalities). In the event that a security is downgraded after its purchase by MassMutual Total Return Bond Fund, the Fund may continue to hold the security if MetWest considers doing so would be consistent with the Fund’s investment objective. MassMutual Total Return Bond Fund may invest up to 25% of its total assets in foreign securities that are denominated in U.S. dollars, up to 15% of its total assets in foreign securities that are not denominated in U.S. dollars, and up to 10% of its total assets in emerging market foreign securities. MassMutual Total Return Bond Fund may but will not necessarily engage in foreign currency forward transactions to take long or short positions in foreign currencies in order to seek to enhance the Fund’s investment return or to seek to hedge or to attempt to protect against adverse changes in currency exchange rates.

MassMutual Core Bond Fund’s investments typically include U.S. dollar-denominated corporate obligations, securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities, U.S. and foreign issuer dollar-denominated bonds including, but not limited to, corporate obligations, government and agency issues, private placement bonds, securities subject to resale pursuant to Rule 144A, and mortgage-backed and other asset-backed securities, including collateralized bond and loan obligations. In the event that a security is downgraded after its purchase by MassMutual Core Bond Fund, the Fund may continue to hold the security if Barings or BIIL considers that doing so would be consistent with the Fund’s investment objective.

Each Fund may hold a portion of its assets in cash or cash equivalents. Each Fund may (but is not obligated to) use a wide variety of additional exchange-traded and over-the-counter derivatives. MassMutual Core Bond Fund may also invest in common stocks, exchange-traded funds (“ETFs”), or other equity securities and derivatives thereof for hedging purposes or to enhance total return. MassMutual Core Bond Fund may also invest in other investment companies. Each Fund purchase and sell securities on a when-issued, delayed delivery, or forward commitment basis, and may enter into repurchase agreement transactions. Each Fund may, at times, have significant exposure to one or more industries or sectors. MassMutual Total Return Bond Fund may normally short sell up to 25% of the value of its total assets for hedging or investment purposes.

Each Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Comparison of Fees and Expenses

The following tables describe the fees and expenses that you may pay if you buy, hold, and sell shares of each of the Funds. You may pay brokerage commissions and other fees to financial intermediaries which are not reflected in the tables and Examples below. For Class A shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in MassMutual Funds. More information about these and other discounts is available in each Fund’s prospectus or from your financial professional. The tables show fees and expenses that the Selling Fund and Acquiring Fund incurred in its most recent fiscal year ended September 30, 2024, as well as pro forma fees and expenses that MML Advisers expects the Acquiring Fund would have incurred during the twelve months ended March 31, 2025, assuming consummation of the Reorganization as of March 31, 2024. In general, a Fund’s annual operating expense ratios will increase as the Fund’s assets decrease and will decrease as the Fund’s assets increase. Accordingly, each Fund’s annual operating expense ratios, if adjusted based on net assets as of the date of this Combined Information Statement/Prospectus, could be higher or lower than those shown in the tables below. The commitment by MML Advisers to waive fees and/or to reimburse expenses for the Acquiring Fund, if applicable and as noted below, may limit the effect that any decrease in the Acquiring Fund’s net assets will have on its annual net operating expense ratios in the current fiscal year. In connection with the Reorganization, MML Advisers agreed to further reduce the expense cap of the Acquiring Fund to match the expense cap of the Selling Fund at the following rates, effective September 15, 2025, through January 31, 2027 at 0.33%, 0.43%, 0.53%, 0.63%, 0.78%, 0.83%, 1.03%, and 0.43% for Classes I, R5, Service, Administrative, R4, A, R3, and Y. In light of this further reduction of the Acquiring Fund’s expense cap, the Reorganization is not expected to result in any change in total expenses for shareholders of the Selling Fund. Additionally, in connection with the Reorganization, MML Advisers agreed to amend the Acquiring Fund’s investment management agreement to decrease the Acquiring Fund’s management fee at the following rates. Pursuant to this amendment, effective September 15, 2025, the Acquiring

Fund’s management fee would be 0.30% annually of the first $2 billion of the Fund’s average daily net assets, and 0.27% annually in excess of $2 billion of the Fund’s average daily net assets. Shareholders of the Selling Fund will not pay any sales charges or redemption fees in connection with the Reorganization. The fees and expenses below exclude one-time costs of the Reorganization, which will be borne by MML Advisers and the Acquiring Fund, as described under the “Costs of the Reorganization” section above and the “Reasons for the Reorganizations and Board Deliberations” section below.

Current and Pro Forma Shareholder Fees

Shareholder Fees (fees paid directly from your investment)

Current and Pro Forma Annual Fund Operating Expenses

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)

(1) Other Expenses are based on estimated amounts for the current fiscal year of the Fund.

(2) The expenses in the above table reflect a written agreement by MML Advisers to cap the fees and expenses of the Fund (other than extraordinary legal and other expenses, Acquired Fund Fees and Expenses, interest expense, expenses related to borrowings, securities lending, leverage, taxes, and brokerage, short sale dividend and loan expense, or other non-recurring or unusual expenses such as organizational expenses and shareholder meeting expenses, as applicable) through January 31, 2026, to the extent that Total Annual Fund Operating Expenses after Expense Reimbursement would otherwise exceed 0.33%, 0.43%, 0.53%, 0.63%, 0.78%, 0.83%, 1.03%, and 0.43% for Classes I, R5, Service, Administrative, R4, A, R3, and Y respectively. The Total Annual Fund Operating Expenses after Expense Reimbursement shown in the above table may exceed these amounts, because, as noted in the previous sentence, certain fees and expenses are excluded from the cap. The agreement can only be terminated by mutual consent of the Board of Trustees on behalf of the Fund and MML Advisers.

(1) The expenses in the above table reflect a written agreement by MML Advisers to cap the fees and expenses of the Fund (other than extraordinary legal and other expenses, Acquired Fund Fees and Expenses, interest expense, expenses related to borrowings, securities lending, leverage, taxes, and brokerage, short sale dividend and loan expense, or other non-recurring or unusual expenses such as organizational expenses and shareholder meeting expenses, as applicable) through January 31, 2026, to the extent that Total Annual Fund Operating Expenses after Expense Reimbursement would otherwise exceed 0.34%, 0.44%, 0.54%, 0.64%, 0.79%, 0.84%, 1.04%, and 0.44% for Classes I, R5, Service, Administrative, R4, A, R3, and Y, respectively. The Total Annual Fund Operating Expenses after Expense Reimbursement shown in the above table may exceed these amounts, because, as noted in the previous sentence, certain fees and expenses are excluded from the cap. The agreement can only be terminated by mutual consent of the Board of Trustees on behalf of the Fund and MML Advisers.

(1) The expenses in the above table reflect the proposed amendment to the Investment Advisory Agreement of the Acquiring Fund to align the Acquiring Fund’s management fee with that of the Selling Fund. Pending Board approval, effective September 15, 2025, the Acquiring Fund’s management fee would be 0.30% annually of the first $2 billion of the Fund’s average daily net assets, and 0.27% annually of the Fund’s average daily net assets in excess of $2 billion.

(2) The expenses in the above table reflect the proposed agreement by MML Advisers in connection with the Reorganization to cap certain fees and expenses of the Acquiring Fund effective September 15, 2025 through January 31, 2027 at 0.33%, 0.43%, 0.53%, 0.63%, 0.78%, 0.83%, 1.03%, and 0.43% for Classes I, R5, Service, Administrative, R4, A, R3, and Y, respectively.

Repositioning Costs

As of the date of this Combined Information Statement/Prospectus, MML Advisers currently expects the Selling Fund will sell approximately 15% of its holdings prior to the Reorganization, the cash proceeds of which will be brought to the Acquiring Fund to be reinvested after the Reorganization. Because the Selling Fund’s fixed income securities are valued at the bid-price, there will be no transaction costs associated with the Selling Fund’s aforementioned sale of holdings prior to the Reorganization. These figures are estimates and the Fund’s actual portfolio realignment may differ.

Expense Examples

The Examples are intended to help you compare the costs of investing in shares of the Selling Fund or the Acquiring Fund with the costs of investing in other mutual funds. The Examples assume that (i) you invest $10,000 in each share class of the relevant Fund for the time periods indicated and then redeem all your shares at the end of those periods, (ii) your investment has a 5% return each year, and (iii) the relevant Fund’s operating expenses are exactly as described in the corresponding preceding Annual Fund Operating Expanses table. For Class A shares, the Examples include the front-end sales charge. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

MassMutual Total Return Bond Fund (Current)

MassMutual Core Bond Fund (Current)

MassMutual Core Bond Fund (Pro Forma) (Combined Fund)

Portfolio Turnover

The Selling Fund and Acquiring Fund pay transaction costs, such as commissions, when they buy and sell securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the expense Examples, affect each of the Funds’ performance. During the most

recent fiscal year, the Selling Fund’s and Acquiring Fund’s portfolio turnover rates, as a percentage of the average value of each Fund’s portfolio, were as follows:

Comparison of Principal Risks

The principal risks associated with investments in the Acquiring Fund and the Selling Fund are comparable because the Funds have comparable investment objectives and comparable principal investment strategies. The following chart identifies the principal risks associated with each Fund. As shown in the chart, the Selling Fund is subject to many of the principal risks of the Acquiring Fund. The actual risks of investing in a Fund depends on the securities the Fund holds and on market conditions, both of which will change over time. Each of the principal risks of the Acquiring Fund appears in Appendix B.

The Funds are subject to many of the same principal risks, but differ primarily given that the Selling Fund is subject to risks associated with investments in below investment grade debt securities, municipal securities, short sales, and sovereign debt obligations, and the Acquiring Fund does not identify these investment risks as principal risks. Additionally, the Acquiring Fund, unlike the Selling Fund, is subject to the risks associated with risks of investments in other funds or pools.

Performance

The following bar charts and tables show, respectively:

The following bar charts and tables below provide some indication of the risks of investing in the Acquiring Fund and Selling Fund by showing changes in each Fund’s annual total returns from year to year for the periods indicated and by comparing each Fund’s average annual total returns for different calendar periods with those of a broad-based index.

MassMutual Total Return Bond Fund

The Selling Fund commenced operations on July 6, 2010. The following bar chart and table provide some indication of the risks of investing in the Selling Fund. The bar chart shows changes in the Selling Fund’s performance from year to year for Class I shares. The table shows how the Selling Fund’s average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance. Performance for Class Y shares of the Selling Fund (which has not yet begun operations, and therefore has no performance history) is based on the performance of Class R5 shares. Performance for Class A shares of the Selling Fund reflects any applicable sales charge. Past performance (before and after taxes) is not necessarily an indication of how the Selling Fund will perform in the future. More up-to-date performance information is available at https://www.massmutual.com/product-performance/mutual-funds or by calling 1-888-309-3539.

Annual Total Returns (for calendar years ended December 31) - Class R5 Shares Before Taxes

Annual Performance

The Selling Fund’s highest/lowest quarterly results during this time period were:

Highest Quarter: 4Q ’23, 7.58%

Lowest Quarter: 1Q ’22, –6.19%

The Selling Fund’s year-to-date total return as of January 1, 2025 - March 31, 2025: 3.05%

Average Annual Total Returns (for periods ended December 31, 2024) Applicable sales charges are reflected

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class I only. After-tax returns for other classes will vary.

MassMutual Core Bond Fund

The Acquiring Fund commenced investment operations on October 3, 1994. The following bar chart and table provide some indication of the risks of investing in the Acquiring Fund. The bar chart shows changes in the Acquiring Fund’s performance from year to year for Class R5 shares. The table shows how the Acquiring Fund’s average annual returns for 1, 5, and 10 years compare with those of a broad measure of market performance. Performance for Class Y shares of the Acquiring Fund for periods prior to its inception date (02/01/23) is based on the performance of Class R5 shares. Performance for Class A shares of the Acquiring Fund reflects any applicable sales charge. Past performance (before and after taxes) is not necessarily an indication of how the Acquiring Fund will perform in the future. More up-to-date performance information is available at https://www.massmutual.com/product-performance/mutual-funds or by calling 1-888-309-3539.

Annual Total Returns (for calendar years ended December 31) - Class R5 Shares Before Taxes

Annual Performance

The Acquiring Fund’s highest/lowest quarterly results during this time period were:

Highest Quarter: 4Q ’23, 7.10%

Lowest Quarter: 2Q ’22, –6.34%

The Acquiring Fund’s year-to-date total return as of January 1, 2025 - March 31, 2025: 2.61%

Average Annual Total Returns (for periods ended December 31, 2024) Applicable sales charges are reflected

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class R5 only. After-tax returns for other classes will vary.

Management

Investment Adviser

MML Advisers, a wholly-owned subsidiary of MassMutual, serves as the investment adviser for the Selling Fund and Acquiring Fund. Following the Reorganization, MML Advisers will continue to serve as the Acquiring Fund’s investment adviser, and the existing subadviser, sub-subadviser, and portfolio management team are expected to remain responsible for the Acquiring Fund.

Investment Subadvisers and Sub-subadviser

MetWest serves as the subadviser for the Selling Fund. Barings serves as the subadviser for the Acquiring Fund, and BIIL serves as the sub-subadviser for the Acquiring Fund and will continue to serve as the Acquiring Fund’s subadviser and sub-subadviser, respectively, following the Reorganization.

Portfolio Managers

It is anticipated that each of the portfolio managers that manage the Acquiring Fund will, upon completion of the Reorganization, continue to manage the Acquiring Fund. Additional information regarding the portfolio managers of the Acquiring Fund can be found in Appendix D.

ADDITIONAL INFORMATION ABOUT EACH REORGANIZATION

Terms of Each Reorganization

As stated above, the Agreement, which provides for the Reorganization of each Selling Fund into the corresponding Acquiring Fund, was previously considered and approved by each Acquiring Trust’s Board and by the Selling Trust’s Board. While shareholders are encouraged to review the Agreement, which has been filed with the SEC as an Exhibit to the Part C of this filing, the following is a summary of certain terms of the Agreement, and is qualified in its entirety by the full text of the Agreement.

Conditions to Closing Each Reorganization

The completion of each Reorganization is subject to certain conditions described in the Agreement, including:

of the Code, (ii) all of the Selling Fund’s investment company taxable income as defined in Section 852 of the Code (computed without regard to any deduction for dividends paid), and (iii) all of the Selling Fund’s net capital gain realized (after reduction for any capital loss carryover), in each case for both the current year (which will end on the closing date) and, if still timely under Section 855 of the Code, the immediately preceding taxable year; and (b) such additional amount, if any, as is necessary to eliminate any liability of the Selling Fund for excise tax under Section 4982 of the Code.

Termination of the Agreement

The Agreement may be terminated with respect to any Reorganization by any party thereto by providing notice to the other parties. In the event of termination of the Agreement, that Reorganization will not proceed and, in the absence of willful default, there shall be no liability for damages on the part of any of the applicable Selling Fund, the applicable Acquiring Fund, the Selling Trust, the Acquiring Trusts or their respective trustees, directors, officers, and affiliates, except that MML Advisers will bear all expenses incurred by the Funds in connection with or arising out of the Agreement (other than any brokerage or other costs relating to transactions in portfolio securities of the Funds). The termination of the Agreement with respect to one Reorganization will not impact the continuation and enforceability of the Agreement as it applies to each other Reorganization (and applicable Selling Funds and Acquiring Funds).

Tax Status of the Reorganizations

Each Reorganization is intended to qualify for U.S. federal income tax purposes as a tax-free reorganization under Section 368(a) of the Code. As a condition to the closing of each Reorganization, the Selling Fund and the Acquiring Fund will receive an opinion from Ropes & Gray LLP substantially to the effect that, on the basis of existing provisions of the Code, U.S. Treasury regulations promulgated thereunder, current administrative rules, and court decisions, while the matter is not free from doubt, generally for U.S. federal income tax purposes:

Each opinion will be based on certain factual representations made by the officers of the Selling Trust and the Acquiring Trusts and will also be based on certain customary assumptions. Each opinion will note and distinguish certain published precedent. It is possible that the Internal Revenue Service (“IRS”) or a court could disagree with Ropes & Gray LLP’s opinion, which therefore cannot be free from doubt.

Opinions of counsel are not binding upon the IRS or the courts. If a Reorganization were consummated but did not qualify as a tax-free reorganization under the Code, a shareholder of the Selling Fund would recognize a taxable gain or loss for U.S. federal income tax purposes equal to the difference between its tax basis in its Selling Fund shares and the fair market value of the Merger Shares it received. Shareholders of a Selling Fund should consult their tax advisers regarding the effect, if any, of the Reorganization in light of their individual circumstances.

With respect to each Reorganization, a substantial portion of the portfolio assets of the Selling Fund may be sold in connection with the Reorganization. The actual tax impact of such sales will depend on the difference between the price at which such portfolio assets are sold and the Selling Fund’s tax basis in such assets. Any net capital gains recognized in these sales will be distributed to the Selling Fund’s shareholders as capital gain dividends (to the extent of net realized long-term capital gains over net realized short-term capital losses) and/or ordinary dividends (to the extent of net realized short-term capital gains over net realized long-term capital losses) during or with respect to the year of sale, and such distributions will be taxable to shareholders. Because the Reorganization will end the tax year of the Selling Fund, it could accelerate distributions to shareholders from the Selling Fund for its short tax year ending on the date of the Reorganization. Those tax year-end distributions will be taxable and will include any capital gains resulting from portfolio turnover prior to the Reorganization.

Prior to the closing of each Reorganization, the Selling Fund will declare a distribution to shareholders, which, together with all previous distributions qualifying for the dividends paid deduction under Section 561 of the Code, will have the effect of distributing to shareholders (a) (i) all of the excess of (x) the Selling Fund’s investment income excludable from gross income under Section 103 of the Code over (y) the Selling Fund’s deductions disallowed under Sections 265 and 171 of the Code, (ii) all of the Selling Fund’s investment company taxable income as defined in Section 852 of the Code, and (iii) all of the Selling Fund’s net capital gain realized (after reduction for any capital loss carryover), provided that the amounts in (i), (ii), and (iii), in each case, shall be computed without regard to the dividends-paid deduction and shall include amounts for both (x) the current year (which will end on the closing date) and (y) the immediately preceding taxable year to the extent such distribution is eligible to be treated as paid during such prior year under Section 855(a) of the Code, and (b) such additional amount, if any, as is necessary to eliminate any liability of the Selling Fund for excise tax under Section 4982 of the Code. These distributions will be taxable to shareholders that hold their shares in a taxable account, and such distributions by the Selling Fund will include any distributable, but undistributed, capital gains resulting from portfolio turnover prior to the Reorganization. In addition, prior to the closing of each Reorganization, the Acquiring Fund may declare a distribution to shareholders with respect to income and gain of the Acquiring Fund earned prior to the closing of the Reorganization. These distributions will be taxable to shareholders that hold their shares in a taxable account.

The ability of the Acquiring Fund following its combination with the Selling Fund (the “Combined Fund”) to carry forward capital losses and to use them to offset future gains may be limited as a result of its Reorganization. First, a Fund’s “pre-acquisition losses” (including capital loss carryforwards, net current-year capital losses, and unrealized losses that exceed certain thresholds) may become unavailable to offset gains of the Combined Fund to the extent such pre-acquisition losses exceed an annual limitation amount. Second, one Fund’s pre-acquisition losses cannot be used to offset gains in another Fund that are unrealized (“built in”) at the time of the Reorganization and that exceed certain thresholds (“non-de minimis built-in gains”) for five tax years. Third, the Selling Fund’s loss carryforwards, as limited under the previous two rules, are permitted to offset only that portion of the gains of the Acquiring Fund for the taxable year of the Reorganization that is equal to the portion of the Acquiring Fund’s taxable year that follows the date of the Reorganization (prorated according to number of days). Therefore, in certain circumstances, shareholders of a Fund may pay taxes sooner, or pay more taxes, than they would have had the Reorganization not occurred.

In addition, the Combined Fund will have tax attributes that generally reflect a blending of the tax attributes of each Fund at the time of the Reorganization (including as affected by the rules described above). Therefore, the shareholders of the Selling Fund will in each case receive a proportionate share of any unrealized gains in the Acquiring Fund’s assets, as well as any taxable income or gains realized by the Acquiring Fund but not distributed to its shareholders prior to the Reorganization, when such income or gains are eventually distributed by the Combined Fund. As a result, shareholders of the Selling Fund may receive a greater amount of taxable distributions than they would have had the Reorganization not occurred. In addition, any pre-acquisition realized losses of the Selling Fund remaining after the operation of the limitation rules described above will become available to offset capital gains realized by the Combined Fund after the Reorganization and thus may reduce subsequent capital gain distributions to a broader group of shareholders than would have been the case absent such Reorganization, such that the benefit of those losses to Selling Fund shareholders may be further reduced relative to what the benefit would have been had the Reorganization not occurred. Further, any pre-acquisition unrealized losses of the Selling Fund at the time of the Reorganization are not expected to be available to offset capital gains realized by the Combined Fund after the Reorganization.

The realized and unrealized gains and losses of each Fund at the time of the Reorganization will determine the extent to which the combining Funds’ respective losses, both realized and unrealized, will be available to reduce gains realized by the Combined Fund following the Reorganization, and consequently the extent to which the Combined Fund may be required to distribute gains to its shareholders earlier or in greater amounts than would have been the case absent the Reorganization. The effect of the rules described above will depend on the relative sizes of, and the losses and gains (both realized and unrealized) in, each Fund at the time of the Reorganization and thus cannot be calculated precisely prior to the Reorganization. The following table provides a brief summary of certain tax attributes of the Acquiring Funds and the Selling Funds as of March 31, 2025. As noted above, the tax effect of a Reorganization depends on each Fund’s relative tax situation at the time of the Reorganization, which situation will be different than the tax situation on March 31, 2025, and cannot be calculated precisely prior to the Reorganization. Portfolio turnover in a Fund, market fluctuations, redemption activity, the nonoccurrence of one or more other

Reorganizations into the same Acquiring Fund, or changes in the tax laws could cause the actual tax effects of the Reorganization to differ substantially from those described herein.

Comparison of Shareholder Rights

Each Selling Fund is a series of the Selling Trust, and each Acquiring Fund is a series of an Acquiring Trust. Each Trust is an open-end management investment company organized as a Massachusetts business trust under the laws of the Commonwealth of Massachusetts by its respective Declaration of Trust. Each Trust is governed by its Declaration of Trust and its Bylaws, and its business and affairs are managed under the supervision of its Board. Each Trust is subject to the federal securities laws, including the 1940 Act, and the rules and regulations promulgated by the SEC thereunder. Each Trust’s Declaration of Trust and Bylaws are substantially identical. Following the Reorganizations, each Selling Fund shareholder will become a shareholder of the corresponding Acquiring Fund and will have substantially the same rights. A copy of each Trust’s Declaration of Trust is on file with the Secretary of the Commonwealth of Massachusetts.

Reasons for the Reorganizations and Board Deliberations

Each Reorganization was reviewed by the Selling Funds’ Board, with the advice and assistance of Fund counsel and independent legal counsel to the Independent Trustees. Information on the Board and its members and governance structure can be found in the Selling Funds’ SAI dated February 1, 2025, as supplemented to date. At a meeting of the Board in March 2025, the Board considered the Reorganization of each Selling Fund, as proposed by MML Advisers. In connection with that Board meeting, MML Advisers provided background materials, analyses, and other information to the Board regarding, among other things, the topics discussed below, and also responded to questions raised by the Board during the meeting.

After the Board reviewed, evaluated, and discussed the materials, analyses, and information provided to it that the Board considered relevant to its deliberations, the Board, including the Independent Trustees, approved the Reorganization of each Selling Fund. Prior to doing so, the Board, including the Independent Trustees, determined that (i) participation in the transaction contemplated by the Agreement is advisable and in the best interest of the Selling Fund and its shareholders, on balance in light of all relevant factors; and (ii) the interests of the existing shareholders of the Selling Fund will not be diluted as a result of the Reorganization.

In reaching the decision to approve the Reorganization for each Fund, the Board considered a number of factors, including, among others, in no order of priority:

In its deliberations, the Board did not identify any single factor that was paramount or controlling and individual Board members may have attributed different weights to various factors. The Board also evaluated the information available to it on a Selling Fund-by-Selling Fund basis, and made determinations separately in respect of each Selling Fund it oversees. Certain of the factors considered by the Board are discussed in more detail below.

STREAMLINED PRODUCT LINE. The Board considered that the Reorganizations are part of a larger effort intended, among other things, to streamline the mutual funds managed by MML Advisers and its affiliates by reducing the number of funds in the MassMutual Fund complex so that management, distribution, and other resources can be focused more effectively on a smaller group of MassMutual Funds. With respect to the Reorganization of MassMutual Total Return Bond Fund into MassMutual Core Bond Fund, reducing the number of funds in the complex is also intended to enhance the fund’s prospects for attracting additional assets by better differentiating the fund for potential shareholders (which may lead to more concentrated selling efforts).

CONTINUED ECONOMIC VIABILITY. The Board noted that, in light of the gross expenses of each Selling Fund, MML Advisers does not view the continued operation of the Selling Funds to be sustainable over the long term. The Board considered MML Advisers’ recommendation that the Reorganization is preferable to other courses of action, including liquidation of the Selling Funds.

COSTS OF THE REORGANIZATIONS. The Board took into account the expected costs of the Reorganizations, including accounting fees, SEC filing fees, and legal fees. The Board weighed these costs against the expected benefits of the Reorganizations.

The Board considered MML Advisers’ recommendation that, with respect to the Equity Opportunities Reorganization, the Selling Fund bear the direct merger costs, legal fees, audit fees, Form N-14 printing and mailing costs, as well as similar expenses incurred in connection with the consummation of the Reorganization and transaction costs (if any) associated with repositioning the Selling Fund prior to the Reorganization. The Board also considered MML Advisers’ recommendation that the Acquiring Fund bear a one-time cost for administratively processing the Equity Opportunities Reorganization. The Board also considered MML Advisers’ recommendation that, with respect to the Total Return Bond Reorganization, MML Adviser bear all expenses incurred by the relevant Selling Fund and Acquiring Fund in connection with or arising out of the transactions contemplated by the Agreement and Plan of Reorganization (other than any brokerage or other costs relating to transactions in portfolio securities of the relevant Funds, which are expected to be immaterial). The Board also considered MML Advisers’ recommendation that the Acquiring Fund bear a one-time cost for administratively processing the Total Return Bond Reorganization.

*     Costs borne by Selling Fund

**   Costs borne by Acquiring Fund

^      Costs borne by MML Advisers

CONTINUITY OF INVESTMENT PROGRAM. The Board took into account the fact that each Selling Fund and its corresponding Acquiring Fund have comparable or substantially similar investment objectives and investment strategies, and that the existing investment adviser, subadviser, sub-subadviser (if any), and portfolio management team is expected to remain the same for each Acquiring Fund. Specifically, the Board noted that with respect to each Reorganization:

Reorganization #1 - MassMutual Equity Opportunities Fund into MassMutual Diversified Value Fund

Among other factors, the Board considered MML Advisers’ representation that the investment objectives of the Selling Fund and the Acquiring Fund are substantially similar, and there will be no changes to the Acquiring Fund’s investment objectives as a result of the Reorganization. Both Funds seek to achieve growth of capital over the long-term. The Acquiring Fund also focuses on growth of income. Additionally, the Acquiring Fund’s objective is to invest primarily in a diversified portfolio of equity securities of larger, well-established companies.

Each Fund’s investment objective and strategies are non-fundamental and may be changed by the Funds’ Board without shareholder approval.

The Board considered MML Advisers’ representation that the Selling Fund’s and Acquiring Fund’s fundamental and non-fundamental investment restrictions are identical, and therefore do not require any changes in connection with the Reorganization.

The Board considered MML Advisers’ representation that the Selling Fund and Acquiring Fund have substantially similar principal investment strategies, and that in MML Advisers’ view, the main differences between the Funds’ strategies is the foreign exposure limit and the number of securities each Fund is expected to hold under normal market conditions. The Selling Fund may invest up to 30% of total assets in securities of foreign issuers and ADRs, and the Acquiring Fund permits up to 25%. The Selling Fund’s exposure to foreign issuers and ADRs as of March 31, 2025 was 6.54% of total assets, and the Acquiring Fund’s exposure to foreign issuers and ADRs as of March 31, 2025 was 1.53% of total assets. Under normal market conditions, the Acquiring Fund expects to hold approximately 175 – 250 stocks. The Selling Fund does not state an expected number of holdings in its principal investment strategies. As of March 31, 2025, the Selling Fund held 63 equity securities, and the Acquiring Fund held 222 equity securities.

Reorganization #2 - MassMutual Total Return Bond Fund into MassMutual Core Bond Fund

Among other factors, the Board considered MML Advisers’ representation that the investment objectives of the Selling Fund and the Acquiring Fund are comparable. Both Funds seek a high rate of total return by investing in fixed-income instruments and securities. The Acquiring Fund specifically seeks to achieve a high total rate of return consistent with prudent investment risk and the preservation of capital, and the Acquiring Fund invests in investment-grade securities.

Each Fund’s investment objective and strategies are non-fundamental and may be changed by each Fund’s Board without shareholder approval.

The Board considered MML Advisers’ representation that the Selling Fund’s and Acquiring Fund’s fundamental investment restrictions are identical, and therefore do not require any changes in connection with the Reorganization. The Board also considered MML Advisers’ representation that the non-fundamental investment restrictions of the Funds are comparable. Other than (i) the Selling Fund’s lack of a short sale restriction, and (ii) one clarification with respect to one of the Acquiring Fund’s restrictions, as discussed the Appendix A, “Comparison of Fundamental Investment Policies” of this Combined Information Statement/Prospectus, the Funds’ non-fundamental investment restrictions are identical. The Funds’ non-fundamental investment restrictions may be changed by a vote of a majority of the Fund’s respective Board at any time without shareholder approval.

The Board considered MML Advisers’ representation that the Selling Fund and Acquiring Fund have comparable principal investment strategies, including that both Funds invest primarily in investment grade fixed income securities, with two notable differences:

the Bloomberg U.S. Aggregate Bond Index. As of December 31, 2024, the Selling Fund’s effective duration was 6.92 years, while the Acquiring Fund’s effective duration was 5.87 years.

The Board considered MML Advisers’ representations that, despite these differences in the Funds’ principal investment strategies, it is expected that the Acquiring Fund presents less credit risk and interest rate risk to shareholders than the Selling Fund and additionally, that the Acquiring Fund has outperformed the Selling Fund over various periods.

EXPENSE RATIO. The Board took into account the fact that each Reorganization has been structured so that shareholders of the Selling Fund will not experience an increase in effective management fee rate, total expense ratio, or Rule 12b-1 fee rate as a result of the Reorganization.

With respect to the Equity Opportunities Reorganization, the Board considered that, based on current net assets as of January 31, 2025, MML Advisers expects such Reorganization will result in a total net expense ratio decrease of approximately 20 bps for all classes of relevant Selling Fund. The Board also considered that the Equity Opportunities Reorganization is expected to result in a total net expense ratio decrease of 8 bps for all classes the relevant Acquiring Fund.

With respect to the Total Return Bond Reorganization, the Board considered that, based on current net assets as of January 31, 2025, MML Advisers expects such Reorganization will result in an equivalent total net expense ratio of 33 basis points for Class I shareholders of the relevant Selling Fund, taking into account the Acquiring Fund’s proposed lower expense cap and reduced management fees in connection with the Reorganization.¹

INVESTMENT PERFORMANCE. The Board considered the relative performance record of each Selling Fund and of each corresponding Acquiring Fund, noting, however, that past performance is no guarantee of future results. Specifically, the Board noted the following with respect to each Reorganization:

Reorganization #1 - MassMutual Equity Opportunities Fund into MassMutual Diversified Value Fund

Among other factors, the Board considered the relative performance of the Funds for periods ending December 31, 2024, noting that the Acquiring Fund outperformed the Selling Fund on an absolute basis for the one-, three-, and five-year periods ended December 31, 2024, and outperformed its style-specific benchmark (Russell 1000 Value Index) for the one-, three-, five-, and ten-year periods ended December 31, 2024. The Board also considered that the Acquiring Fund ranked in the top third of its Morningstar category (large cap value) for the one-, three, and ten-year periods ended December 31, 2024; whereas, the Selling Fund has ranked in bottom quartile of its Morningstar category (large cap blend) for the one-, three-, five-, and ten-year periods ended December 31, 2024. The Board considered that the Acquiring Fund is currently managed solely by Brandywine Global; however, prior to March 26, 2024, T. Rowe Price co-managed the Fund with Brandywine Global. The Board noted that prior to March 26, 2024, T. Rowe Price was responsible for approximately 25% of the Acquiring Fund, and the Fund’s performance returns prior to March 26, 2024 reflect the blend of these two subadvisers.

Reorganization #2 - MassMutual Total Return Bond Fund into MassMutual Core Bond Fund

Among other factors, the Board considered the relative performance of the Funds for periods ending December 31, 2024, noting that the Acquiring Fund outperformed the Selling Fund on an absolute basis for the one-, three-, five-, and ten-year periods ended December 31, 2024, and outperformed its benchmark (Bloomberg U.S. Aggregate Bond Index) for the one-, three-, five-, and ten-year periods ended December 31, 2024. The Acquiring Fund has ranked in the top third of its Morningstar category (intermediate core bond) for the one-, three-, five-, and ten-year periods ended December 31, 2024, whereas the Selling Fund has ranked in bottom quartile of its Morningstar

¹       Effective February 1, 2025, MML Advisers agreed to reduce the Acquiring Fund’s expense cap by 8 basis points for each share class. In connection with the Merger, Management is proposing to further reduce the Acquiring Fund’s expense cap. Effective September 15, 2025 through January 31, 2027, the Acquiring Fund’s expense cap would decrease by 1 basis point for each share class, to align with the expense caps in place for the Selling Fund. Additionally, in connection with the Merger, effective September 15, 2025, the Acquiring Fund’s management fee would be 0.30% annually of the first $2 billion of the Fund’s average daily net assets, and 0.27% annually of the Fund’s average daily net assets in excess of $2 billion.

category (intermediate core-plus bond) for the one- and three-year periods and bottom half for the five- and ten-year periods ended December 31, 2024.

ECONOMIES OF SCALE. The Board considered the potential to realize immediate economies associated with consolidating each Selling Fund into a larger combined fund. The Board also considered that the MassMutual Core Bond Fund may over time be able to take further advantage of economies of scale associated with larger funds. MML Advisers informed the Board that it believes that following the Reorganization, the MassMutual Core Bond Fund will have better prospects for attracting assets than the Selling Fund. With respect to each Combined Fund, the Board considered that a larger fund may benefit from fee breakpoints more quickly, may have an enhanced ability to effect portfolio transactions on favorable terms, and may have greater investment flexibility.

TAX CONSEQUENCES. The Board examined the relative tax situations of the Selling Funds and the corresponding Acquiring Funds. The Board also considered the anticipated tax-free nature of the exchange of shares in the Reorganizations, and other expected U.S. federal income tax consequences of the Reorganizations (such as the resulting tax impact of each proposed Reorganization to the Selling Funds’ shareholders, including the considerations concerning the effect of loss and loss carryforward positions of the affected Funds, if any).

Each Reorganization was also reviewed by each Acquiring Funds’ Board, with the advice and assistance of Fund counsel and independent legal counsel to the Acquiring Funds’ Independent Trustees. At the meeting of the Board in March 2025, each Acquiring Fund’s Board considered the Reorganization of each Selling Fund into the corresponding Acquiring Fund and determined that participation by each Acquiring Fund overseen by it in its Reorganization was in the best interests of the Acquiring Fund, on balance in light of all relevant factors, and that the interests of existing shareholders of the Acquiring Fund would not be diluted as a result of the Reorganization.

As noted above, the Board, including the Independent Trustees, unanimously approved the Reorganization of each Selling Fund. In accordance with each Fund’s Declaration of Trust and applicable state and U.S. federal law (including Rule 17a-8 under the 1940 Act), each Reorganization may be effected without the approval of shareholders of a Fund.

CAPITALIZATION

Current and Pro Forma Capitalization of each Selling Fund and each Acquiring Fund

The following table shows on an unaudited basis the capitalization of each Selling Fund and Acquiring Fund as of March 31, 2025 and the pro forma capitalization of each Combined Fund as of March 31, 2025 assuming the Reorganizations had occurred on that date.

Reorganization #1 - MassMutual Equity Opportunities Fund into MassMutual Diversified Value Fund

Reorganization #2 - MassMutual Total Return Bond Fund into MassMutual Core Bond Fund

CONTROL PERSONS AND PRINCIPAL HOLDERS OF SECURITIES

As of [May 31, 2025], to the Selling Trust’s knowledge, the following persons owned of record or beneficially 5% or more of the outstanding shares of the indicated classes of the Selling Funds set forth below. Such ownership may be beneficially held by individuals or entities other than the owner listed. To the extent that any listed shareholder beneficially owns more than 25% of a Selling Fund, it may be deemed to “control” such Fund within the meaning of the 1940 Act. The effect of such control may be to reduce the ability of other shareholders of the Selling Fund to take actions requiring the affirmative vote of holders of a plurality or majority of the Selling Fund’s shares without the approval of the controlling shareholder. As of [May 31, 2025], the Trustees and officers of the Selling Trust, individually and as a group, did not beneficially own outstanding shares of any Fund that is a series of the Selling Trust.

MassMutual Equity Opportunities Fund¹

MassMutual Total Return Bond Fund²

MassMutual Diversified Value Fund³

MassMutual Core Bond Fund⁴

MassMutual Diversified Value Fund⁵

MassMutual Core Bond Fund⁶

as that term is defined in the 1940 Act. However, such ownership may be beneficially held by individuals or entities other than MassMutual. MassMutual is organized under the laws of Massachusetts.]

FINANCIAL HIGHLIGHTS OF THE ACQUIRING FUNDS

The financial highlights tables are intended to help you understand the Acquiring Funds’ financial performance for the past 5 years. Certain information reflects financial results for a single Fund share. The total returns in the tables represent the rate that an investor would have earned on an investment in the Fund (assuming reinvestment of all dividends and distributions). Past performance is not necessarily an indication of future results. Other than the information for the six-month period ended March 31, 2025, which is unaudited, the information in the following tables has been derived from the Acquiring Funds’ financial statements, which have been audited by Deloitte & Touche LLP, 115 Federal Street, Boston, Massachusetts 02110, an independent registered public accounting firm, whose report, along with each Acquiring Fund’s financial statements, is included in such Acquiring Funds’ Form N-CSR, which is available on request.

Financial Highlights - MassMutual Diversified Value Fund

Financial Highlights - MassMutual Core Bond Fund