UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

Information Required In Proxy Statement

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ARTHUR J. GALLAGHER & CO.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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Arthur J. Gallagher & Co.

2850 Golf Road

Rolling Meadows, Illinois 60008-4050

Notice of 2025 Annual Meeting of Stockholders

Dear Stockholder:

We are pleased to invite you to the 2025 Annual Meeting of Stockholders of Arthur J. Gallagher & Co. (Gallagher or the company), which will be held as a virtual meeting, conducted via live audio webcast, on May 13, 2025, at 9:00 AM CDT. At the meeting, stockholders will vote on each item described below and we will transact such other business that properly comes before the meeting.

Stockholders of record at the close of business on March 17, 2025 are entitled to notice of and to vote at the Annual Meeting. The applicable voting standard and the treatment of abstentions and “broker non-votes” for each of these items are set forth on page 49 of the Proxy Statement. Stockholders may vote shares prior to the meeting by visiting www.proxyvote.com.

On the day of the Annual Meeting, stockholders of record as of the close of business on March 17, 2025, the record date, are entitled to participate in and vote at the Annual Meeting. To participate in the Annual Meeting, including to vote and ask questions, stockholders of record should go to the meeting website at www.virtualshareholdermeeting.com/AJG2025, enter the 16-digit control number found on your proxy card or Notice of Internet Availability of Proxy Materials, and follow the instructions on the website. If your shares are held in street name and your voting instruction form or Notice of Internet Availability of Proxy Materials indicates that you may vote those shares through the www.proxyvote.com website, then you may access, participate in, and vote at the Annual Meeting with the 16-digit access code indicated on that voting instruction form or Notice of Internet Availability of Proxy Materials. Otherwise, stockholders who hold their shares in street name should contact their bank, broker or other nominee (preferably at least 5 days before the Annual Meeting) and obtain a “legal proxy” in order to be able to attend, participate in or vote at the Annual Meeting.

Stockholders are encouraged to log in to the Annual Meeting website before the Annual Meeting begins. Online check-in will be available approximately 10 minutes before the meeting starts. Additional information regarding the rules and procedures for participating in the virtual Annual Meeting will be set forth in our meeting rules of conduct, which stockholders will be able to view during the meeting.

We urge you to read the Proxy Statement for additional information concerning the matters to be considered at the Annual Meeting and then vote in accordance with the Board’s recommendations. Your vote is very important to us.

By Order of the Board of Directors

WALTER D. BAY

GENERAL COUNSEL AND SECRETARY

March 24, 2025

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders to Be Held on May 13, 2025:

We are making this Notice of Annual Meeting, this Proxy Statement, our 2024 Annual Report, and the Notice of Internet Availability of Proxy Materials available on the Internet at www.materials.proxyvote.com/363576 and mailing copies of these proxy materials to certain stockholders on or about March 24, 2025.

Corporate Governance

ITEM 1 – Election of Directors

Evaluation Process for Director Candidates

The Nominating/Governance Committee considers director candidates suggested by stockholders, management or other members of the Board of Directors (Board) and may hire consultants or search firms to help identify and evaluate potential director candidates. In some cases, nominees have been individuals known to Board members or others. In the case of Richard Harries, a member of senior management initially identified him as a potential director nominee. Prior to his nomination, Mr. Harries met separately with the Chairman and CEO and each member of the Nominating/Governance Committee (which includes our Independent Lead Director), who considered his candidacy. After review and discussion, the Nominating/Governance Committee recommended, and the Board approved, Mr. Harries's appointment to the Board. For information regarding how stockholders can submit a director candidate for consideration by the Nominating/Governance Committee, as well as for information regarding “proxy access,” see page 51.

The Nominating/Governance Committee evaluates director candidates by considering their judgment, qualifications, attributes, skills, integrity, gender, racial/ethnic diversity, international business or other experience relevant to our global activities and other factors it deems appropriate. The Committee looks for candidates who are leaders in the organizations with which they are affiliated and have experience in positions with a high degree of responsibility. The Committee seeks candidates free from relationships or conflicts of interest that could interfere with the director’s duties to Gallagher or our stockholders. The Committee also evaluates candidates’ independence and takes into account applicable requirements under Securities and Exchange Commission (SEC) rules and New York Stock Exchange (NYSE) listing standards.

Board Diversity

Our Board nominees reflect diversity of professional background, experiences, viewpoints, gender, race/ethnicity, tenure, nationality and age. Our Board has adopted the “Rooney Rule” for director searches. Under this policy, our Governance Guidelines provide that, when recruiting director candidates, the Nominating/Governance Committee endeavors to include qualified diverse candidates, and requests that any search firm it engages endeavor to do the same, including women and racially/ethnically diverse persons to expand the pool from which new director nominees are ultimately chosen based on merit. The Committee actively seeks Board members from diverse backgrounds who combine a broad spectrum of experience and expertise with a reputation for integrity. The Committee assesses the effectiveness of the Board’s diversity search policy as part of its annual review process.

These percentages include our Chairman and CEO, Pat Gallagher.

Board Nominees and Vote Required

Upon the recommendation of the Nominating/Governance Committee, the Board has nominated our Chairman and Chief Executive Officer (CEO) and each of the additional nine individuals listed below to hold office until the next annual meeting and the election and qualification of their successors or, if earlier, until their resignation, death or removal. Each of the nominees currently serves on the Board and, except for Mr. Harries who was appointed in July 2024, was last elected at the 2024 annual meeting, and all of the nominees have consented to serve on the Board if elected. If any nominee should become unable or unwilling to serve, the Board may nominate another person to stand for election or reduce the size of the Board.

Each director nominee who receives more “FOR” votes than “AGAINST” votes at the Annual Meeting will be elected. Abstentions will have the same effect as a vote “AGAINST.” Any incumbent director nominee who receives a greater number of votes

“AGAINST” election than votes “FOR” election is required to tender an offer of resignation for consideration by the Nominating/Governance Committee in accordance with our Governance Guidelines.

Director Qualifications

We have summarized below the key qualifications and areas of experience that led our Board to conclude that each non-management director nominee is qualified to serve on our Board; however, this is not intended to be an exhaustive list of their qualifications or contributions to our Board.

Key Governance Practices

The Board and Nominating/Governance Committee continually evaluate governance best practices and consider modifications to our corporate governance that support our strategic objectives, protect the long-term interests of our stockholders and promote management accountability. Set forth below are several key governance practices:
 

Board Leadership Structure

Pat Gallagher currently serves as Chairman of the Board and CEO. With the exception of Messrs. Gallagher and Coldman, all Board members are independent and actively oversee the activities of the Chairman and other members of the senior management team. We believe that our Board leadership structure allows us to take advantage of Pat Gallagher’s extensive experience and knowledge of our business, which enriches the Board’s decision making. Pat Gallagher’s role as Chairman and CEO also enhances communication and coordination between management and the Board on critical issues.

David Johnson has served as our Independent Lead Director since 2016. The duties and responsibilities of the Independent Lead Director are set forth below.

Our non-management and independent directors meet regularly in executive sessions. Executive sessions are held at the beginning and at the end of each regularly scheduled in-person or virtual Board meeting. Other executive sessions may be called by the Independent Lead Director at his discretion or at the request of the Board. Executive sessions at the full-Board level are chaired by our Independent Lead Director. The committees of the Board also meet regularly in executive sessions.

The Board believes that its leadership structure as described above provides an effective framework for addressing the risks and opportunities facing our company, as it effectively allocates authority, responsibility, and oversight between management and the Board. The Board believes the role of the Independent Lead Director underscores our continuing commitment to strong corporate

governance and Board independence. The Board believes that the Independent Lead Director’s ability to call meetings of the Board when necessary improves the independence of the Board’s leadership structure and its role in risk oversight.

Director Independence

The Board has conducted its annual review of the independence of each director nominee under NYSE standards and the independence standards set forth in Appendix A of our Governance Guidelines (available on our website located at www.ajg.com/ir, under the heading “Corporate Governance”). Based upon its review, the Board has concluded in its business judgment that, with the exception of Pat Gallagher and John Coldman, each of the other director nominees (Sherry Barrat, Deborah Caplan, Teresa Clarke, Richard Harries, David Johnson, Chris Miskel, Ralph Nicoletti, and Norman Rosenthal) is independent. William Bax, who did not stand for re-election at the 2024 Annual Meeting, was independent during the time he served on the Board.

Compensation Committee Interlocks and Insider Participation

During 2024, Sherry Barrat, Deborah Caplan, David Johnson and Chris Miskel served on the Compensation Committee with Sherry Barrat serving as Chair. None of the members of the Board who served on the Compensation Committee is a former or current officer or employee of the company or any of our subsidiaries, is involved in a relationship requiring disclosure as an interlocking executive officer or director or had any relationship requiring disclosure under Item 404 of Regulation S-K.

Stockholder Views

Our Board pays close attention to the views of our stockholders, including the 90.3% approval rate received for our “say on pay” proposal in 2024, when making determinations regarding corporate governance and executive compensation. During the past year, members of our management team and Board engaged with stockholders representing more than 50% of our outstanding shares to discuss various governance, executive compensation and sustainability matters.

Board’s Role in Risk Oversight

The Board has delegated primary responsibility for risk oversight to the Risk and Compliance Committee. However, the Board retains overall responsibility for risk oversight, reviews significant risk matters at the full-Board level when appropriate, regularly discusses CEO succession planning, including emergency succession plans, and provides oversight of succession planning for certain other senior management positions in consultation with the CEO.

The Risk and Compliance Committee oversees enterprise risk management (ERM) and compliance with laws and regulations. Among other things, the Committee regularly reviews our major risk exposures and management’s activities to mitigate and monitor such exposures; reviews our process for identifying and assessing risks, including emerging risks; reviews and discusses with management our risk appetite statements; reviews our business continuity and crisis management framework, including our incident response plans and reviews our ethics and compliance program, including our Global Standards of Business Conduct and significant legal and regulatory compliance matters. We have a management-level ERM Committee consisting of a Chair and senior personnel representing functional, business and geographic areas across the company, with broad oversight of ERM. The Chair of the ERM Committee, Chief Compliance Officer, Chief Information Officer and Chief Information Security Officer attend each meeting of the Risk and Compliance Committee, as well as regular meetings of the senior executive team dedicated to compliance and risk, and report on our most significant risk exposures. These include significant compliance, data privacy, cybersecurity, sustainability and artificial intelligence matters. See page 10 below for additional information regarding the responsibilities and activities of the Risk and Compliance Committee.

The other committees of the Board oversee the management of risks within their areas of responsibility. The Risk and Compliance Committee coordinates and communicates with these other committees as appropriate. In addition, to facilitate coordination and communication between the committees with respect to risk matters, the Risk and Compliance Committee includes at least one member from each other committee. The Risk and Compliance Committee (and each other committee as appropriate) reports regularly to the Board regarding our major risks and steps undertaken to monitor and mitigate such risks.

For each committee of the Board, the tables below set forth its primary responsibilities, including certain key matters relating to risk oversight, as well as its membership, independence, and number of meetings held in 2024. See “Sustainability Oversight and Activities” beginning on page 12 for information regarding each committee’s role in overseeing sustainability matters.

Sustainability Oversight and Activities

The Board maintains overall oversight of sustainability matters. Each Board committee oversees sustainability matters within its scope of responsibility as described below and reports to the full Board as appropriate. In addition, from time to time, the full Board receives presentations regarding key sustainability topics.

Audit Committee. The Audit Committee reviews ERM with the assistance of the Risk and Compliance Committee, including sustainability matters such as climate and cybersecurity risks. The Audit Committee also reviews our tax strategies.

Compensation Committee. The Compensation Committee reviews our strategies and policies related to human capital management, including workplace environment and culture, and talent development and retention.

Nominating/Governance Committee. The Nominating/Governance Committee oversees our corporate governance principles and practices, and receives regular updates on governance developments from the General Counsel and other members of management. As part of succession planning for the Board and key Board and committee leadership roles, and in support of its strategy to promote diversity on the Board, the Board adopted a policy that the Nominating/Governance Committee endeavor to include qualified diverse candidates, including women and racially/ethnically diverse persons to expand the pool from which new director nominees are ultimately chosen based on merit.

Risk and Compliance Committee. The Risk and Compliance Committee reviews and discusses a variety of sustainability-related risks and related mitigation strategies identified by the management-level ERM Committee and senior executive team. These include risks relating to human capital management, cybersecurity, data privacy, reputation and climate change. On a quarterly basis, the Chief Information Officer and Chief Information Security Officer update the Committee on our cybersecurity program. In addition, the Committee has responsibility for reviewing our ethics and compliance program, including the Global Standards of Business Conduct, and receives regular reports from the Chief Compliance Officer.

Sustainability Activities. The company has a management-level committee consisting of employees from across our global businesses and corporate departments, with responsibility for coordinating and communicating the company’s sustainability initiatives. Our Impact Report, EEO-1 Employer Information Report and other sustainability-related materials can be found on our website at investor.ajg.com/esg. The Impact Report includes our goal to reach operational net zero carbon emissions (Scope 1 and Scope 2) by 2050 and our interim goal of a consolidated 50% reduction in such emissions, on a per-employee basis, by 2030. It also highlights how we help our clients manage climate-related risks and other sustainability-related client services. In our disclosures, we aim to align with the Global Reporting Initiative (GRI) Standards, the Sustainability Accounting Standards Board (SASB) standards and the Task Force on Climate-related Financial Disclosure (TCFD) recommendations. Such reports and other information on our website are not deemed part of this Proxy Statement and are not incorporated by reference.

Other Board Matters

Attendance. The Board expects each director to attend and participate in all Board and applicable committee meetings and annual meetings of stockholders. Each director is expected to prepare for meetings in advance and to dedicate the time necessary to discharge properly their responsibilities at each meeting and to ensure other commitments do not materially interfere with their service on the Board. During 2024, the Board met 12 times. All of the current directors attended 75% or more of the aggregate meetings of the Board and committees on which they served during 2024. In addition, all directors then serving on the Board attended the 2024 Annual Meeting.

Stockholder Communications with the Board. A stockholder or other party interested in communicating with the Board, any of its committees, the Chairman, the Independent Lead Director, the non-management directors as a group or any director individually may do so by writing to the attention of the Corporate Secretary at our principal executive offices, Arthur J. Gallagher & Co., c/o Corporate Secretary, 2850 Golf Road, Rolling Meadows, Illinois 60008-4050. Where appropriate, our Independent Lead Director is available for consultation and communication with stockholders.

Corporate Governance Materials. We are committed to sound and effective corporate governance. To that end, the Board has adopted Governance Guidelines that set forth principles to assist it in determining director independence and other important corporate governance matters. The Board has also adopted Global Standards of Business Conduct (the Global Standards) that apply to all directors, executive officers and other employees. The Global Standards, along with our Governance Guidelines and the charters of the Audit, Compensation, Nominating/Governance and Risk and Compliance Committees, are available at www.ajg.com/ir, under the heading “Corporate Governance.” We intend to satisfy the disclosure requirements of Item 5.05 of Form 8-K regarding any amendment to, or waiver from, the Global Standards with respect to any of our directors or executive officers by posting such information on our website.

Insider Trading Policy. We have an Insider Trading Policy covering transactions in our securities that applies to directors, officers, employees and certain of their family members and controlled entities. The policy may also apply to other persons such as consultants or contractors designated by the company. Our Insider Trading Policy states that transactions by the company in our own securities will comply with applicable securities and state laws. We believe our Insider Trading Policy is reasonably designed to promote compliance with insider trading laws, rules, regulations and listing standards applicable to us. For additional details, please refer to our Insider Trading Policy, which we filed as Exhibit 19.1 to our Annual Report on Form 10-K for the year ended December 31, 2024.

Director Compensation

The Board sets the amount and form of non-management director compensation based upon recommendations made by the Nominating/Governance Committee. In 2024, the Nominating/Governance Committee engaged Pearl Meyer & Partners, LLC (Pearl Meyer) to assess the competitiveness of our director pay program against the same peer group that is used to assess the competitiveness of our executive compensation program and a "Top 200" large company survey. Pearl Meyer found that pay levels for our Board were below the 50th percentile of our peer group and between the 50th and 75th percentile of the Top 200 survey. Taking these benchmark results into consideration, in 2024, the target value of the annual equity grant was increased from $190,000 to $200,000 and the annual cash retainer was increased from $125,000 to $130,000. In addition, the annual fee for the Independent Lead Director was increased from $35,000 to $40,000, and the annual fee for the Audit Committee Chair was increased from $30,000 to $35,000. The other Committee Chair fees remained the same, as follows: $25,000 for each of the Compensation Committee and Risk and Compliance Committee and $20,000 for the Nominating/Governance Committee. Pearl Meyer found that pay levels for our Board would be between the 50th and 75th percentiles of both benchmarks once we implemented these changes.

On May 7, 2024, each non-management director was granted 850 restricted stock units (RSUs) that vest on the first anniversary of the date of grant (or immediately upon a director’s departure from the Board). Richard Harries, who joined the Board on July 24, 2024, was granted a prorated award of 669 RSUs as of such date. Under our stock ownership guidelines, directors with at least five years of service are expected to own an amount of our common stock with a value equal to five times the cash portion of the annual director retainer. All of our directors with five or more years of service meet these guidelines.

Non-management directors may elect to defer all or a portion of their annual cash retainer or RSUs under our Deferral Plan for Nonemployee Directors. Deferred cash retainers and RSUs are converted to notional stock units, which are credited to individuals’ accounts along with dividend equivalents when dividends are paid on our common stock. Deferred amounts credited to directors' individual accounts are distributed in the form of common stock at a date specified by each director or upon such director’s departure from the Board.

Directors are reimbursed for travel and accommodation expenses incurred in connection with attending Board and committee meetings.

Certain Relationships and Related Person Transactions

How We Review and Approve Related Person Transactions

The company maintains a written Related Person Transactions Policy. We review all relationships and transactions exceeding $120,000 in which the company participates and in which any related person (our directors and executive officers or their immediate family members and any persons owning 5% or more of our common stock) had or will have a direct or indirect material interest, subject to certain exceptions. These include certain transactions that do not require disclosure under Item 404 of Regulation S-K, such as compensation of our executive officers and directors, among others, and which are deemed pre-approved under our Related Person Transactions Policy. The company’s legal staff is primarily responsible for reviewing such relationships and transactions based on the facts and circumstances, and for developing and implementing processes and controls for obtaining and evaluating information about related person transactions. As required by SEC rules, we disclose in this Proxy Statement all such transactions that are determined to be directly or indirectly material to a related person and that are required to be disclosed under Item 404 of Regulation S-K. In addition, the Nominating/Governance Committee reviews and approves or disapproves any such related person transaction. In the course of reviewing and determining whether or not to approve a disclosable related person transaction, the Committee considers the following factors:

Related Person Transactions for 2024

Tom Gallagher, our President and one of our named executive officers, is the brother of our CEO. His compensation was approved by the Compensation Committee and is disclosed in the 2024 Summary Compensation Table below. In 2024, the following relatives of Tom Gallagher were employed with us: (i) Michael Gallagher, his son, is a branch manager within our brokerage segment, and received total compensation of $794,578, and (ii) Kevin Gallagher, his son, is a strategic planning leader within our brokerage segment, and received total compensation of $525,716.

Patrick Gallagher, our Chief Operating Officer, is the son of our CEO. His compensation was approved by the Compensation Committee and is disclosed in the 2024 Summary Compensation Table below.

In 2024, the following additional relatives of Pat Gallagher, our CEO, were employed with us: (i) Jennifer Gallagher, his sister, is head of a specialty sales unit within our brokerage segment and received total compensation of $1,289,219; (ii) Shannon Gallagher, his daughter, is a marketing partnership development manager and received total compensation of $566,195; (iii) Sean Gallagher, his son, is a regional manager within our brokerage segment and received total compensation of $1,286,733; and (iv) Brendan Gallagher, his son, is a branch manager within our brokerage segment and received total compensation of $1,409,666.

Jonathan Hudson, the son of Scott Hudson, President of our risk management segment, is a producer in our brokerage segment and received total compensation of $387,549 for 2024. Norah Shipman, daughter of David Johnson, one of our directors, is an account manager in our brokerage segment and received total compensation of $133,566 for 2024. John Bickhart, the son-in-law of Doug Howell, our Chief Financial Officer, is a business systems analyst lead and received total compensation of $335,000.

The following relatives of Mike Pesch, our Chief Executive Officer, Global Brokerage - Americas, were employed with us in 2024: (i) Derek Van der Voort, his brother-in-law, is a branch manager in our brokerage segment and received total compensation of $851,219, and (ii) Wes Van der Voort, his brother-in-law, is a branch manager in our brokerage segment and received total compensation of $889,501.

The total compensation (salary, bonus, and the grant value of equity and cash awards) of each related person described above was commensurate with that of other employees with equivalent qualifications and responsibilities and holding similar positions.

Security Ownership by Certain Beneficial Owners and Management

The table below presents information concerning beneficial ownership of our common stock by: (i) each person we know to be the beneficial owner of more than 5% of our outstanding shares of common stock (as of the date indicated in the footnotes below); (ii) each of our named executive officers, directors and director nominees (as of March 17, 2025); and (iii) all of our executive officers and directors as a group (as of March 17, 2025). The percentage calculations in this table are based on a total of 255,734,802 shares of our common stock outstanding as of the close of business on March 17, 2025. Unless otherwise indicated below, to our knowledge, the individuals and entities named in the table have sole voting and sole investment power with respect to all shares beneficially owned by them, subject to community property laws where applicable.