Proxy Statement (Form DEF 14A)

Proxy 2026 Statement Annual Meeting Notice & proxy Statement

Notice of Annual Meeting of Shareholders

The 2026 Annual Meeting of Shareholders of Trustmark Corporation (Trustmark) will be held as follows:

DATE AND TIME

Tuesday, April 28, 2026, at 1:00 p.m. CT

VIRTUAL ATTENDANCE

The Annual Meeting will be held virtually. You will be able to attend, vote and submit questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/TRMK2026and entering the 16-digit control number printed in the box marked by the arrow on your proxy card or printed on your voting instruction form, Notice of Internet Availability of Proxy Materials, or email previously received.

ITEMS OF BUSINESS

RECORD DATE

Shareholders of record on March 2, 2026, are entitled to notice of and to vote at the Annual Meeting.

PROXY VOTING/REVOCATION

Your vote is important. You are urged to vote your shares as soon as possible, whether or not you plan to attend the meeting. Please vote your shares in one of the following ways:

If you attend the virtual meeting, you may revoke your proxy prior to the voting thereof. You may also revoke your proxy by following the instructions on page 4 of the proxy statement.

Granville Tate, Jr.

Secretary

March 16, 2026

March 16, 2026

Dear Shareholder:

On behalf of your Board of Directors, we cordially invite you to attend Trustmark's Annual Shareholders' Meeting, which will be held virtually on April 28, 2026, at 1:00 p.m. CT. At the meeting, you will have the opportunity to elect 11 directors who bring diverse perspectives and valuable leadership skills to Trustmark. Their guidance will enable us to successfully compete in an evolving industry and continue our steadfast commitment to the customers, associates, shareholders, and communities we have the privilege of serving. Your vote is important to us. The proposals to be considered are described in this proxy statement, and instructions on how to vote your shares may be found on page 4. We encourage you to vote your shares in advance of the meeting to ensure the presence of a quorum.

Trustmark's momentum continued to build throughout the year, resulting in record earnings in 2025. Our traditional banking business drove continued loan and deposit growth, a strong net interest margin, and solid credit quality. Our mortgage banking business achieved increased production and significant improvement in profitability while revenue in our wealth management business reached an all-timehigh. We have a tremendous team of associates focused on expanding customer relationships and demonstrating the value Trustmark can provide as their trusted financial partner. Looking forward, we will continue to build upon this momentum and pursue opportunities to leverage investments in technology that will broaden our reach, enhance customer experience, and improve efficiency. Trustmark is well-positioned to meet the needs of our customers and build long-term value for our shareholders.

We invite you to review our Form 10-Kand our 2025 Year in Review, both of which are available at investorrelations.trustmark.com or in hard copy upon request. These documents will provide more detailed information about your company.

Thank you for your continued support of Trustmark and your participation in this important process.

Sincerely,

TABLE OF CONTENTS

PROXY SUMMARY

This summary highlights information contained elsewhere in this proxy statement. Please read the entire proxy statement carefully before voting as this is only a summary.

Information About the 2026 Annual Meeting

Proposals

Financial Highlights - 2025

For more information on return on average tangible equity and tangible book value per share, which are non-GAAPfinancial measures, including a reconciliation of such measures to amounts reported under U.S. generally accepted accounting principles (GAAP), please see the section entitled "Non-GAAPFinancial Measures" in Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations in Trustmark's Annual Report on Form 10-Kfor the year ended December 31, 2025 (2025 Form 10-K)filed with the SEC on February 23, 2026.

Corporate Governance Highlights

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GENERAL INFORMATION

Introduction

Trustmark Corporation (Trustmark) is holding its 2026 Annual Meeting of Shareholders (the Annual Meeting) on Tuesday, April 28, 2026. This proxy statement is being sent on or about March 16, 2026, in connection with the solicitation by the Board of proxies to be voted at the Annual Meeting and at any adjournment or postponement thereof.

Trustmark is furnishing this proxy statement over the Internet to most shareholders. These shareholders will not receive printed copies of the proxy statement and proxy card, and instead will receive a Notice of Internet Availability of Proxy Materials containing instructions on how to access the proxy materials over the Internet. If you received a Notice of Internet Availability of Proxy Materials, please see "Availability of Proxy Materials" on page 49 for additional information.

Meeting Date and Time

The Annual Meeting will be held in a virtual-only format on Tuesday, April 28, 2026, at 1:00 p.m. CT. You will be able to attend, vote and submit questions during the Annual Meeting by visiting www.virtualshareholdermeeting.com/TRMK2026and entering the 16-digitcontrol number printed in the box marked by the arrow on your proxy card or printed on your voting instruction form, Notice of Internet Availability of Proxy Materials, or email previously received.

Shareholders Entitled to Vote

Shareholders of record at the close of business on March 2, 2026, are entitled to notice of and to vote at the Annual Meeting. On the record date, Trustmark had outstanding 58,871,879 shares of common stock.

Required Vote

A majority of the shares outstanding and entitled to vote constitutes a quorum to transact business at the Annual Meeting. Each share is entitled to one vote on each proposal.

The required vote for each proposal is as follows:

While abstentions and broker non-votesare counted as shares present at the meeting for purposes of determining a quorum, they are not otherwise counted and, therefore, will have no effect on the outcome of the election of directors or any other proposal.

Applicable rules determine whether proposals presented at shareholder meetings are considered routine or non-routine.If a proposal is considered routine, a bank, broker or other holder of record, which holds shares for an owner in street name generally may vote on the proposal without receiving voting instructions from the beneficial owner. If a proposal is non-routine,the bank, broker or other holder of record generally may vote on the proposal only if the beneficial owner has provided voting instructions. A "broker non-vote"occurs when a broker or other entity returns a signed proxy card but does not vote shares on a particular proposal because the proposal is not a routine matter, and the broker or other entity has not received voting instructions from the beneficial owner of the shares. The ratification of the selection of Crowe as independent auditor is considered a routine matter, while the other proposals, i.e., the election of directors and the advisory vote to approve Trustmark's executive compensation, are considered non-routinematters.

All valid proxies received by Trustmark will be voted in accordance with the instructions indicated in such proxies. As noted above, if you hold your shares through a bank, broker or other holder of record and you do not give voting instructions, your bank, broker or other record holder of the shares is not permitted to vote your shares on any proposal other than Proposal 3, which is the only routine proposal on the agenda. If no instructions are indicated in an otherwise properly executed proxy, it will be voted FOR each director nominee named in Proposal 1, FOR advisory approval of Trustmark's executive compensation in Proposal 2, FOR ratification of the selection of Crowe as independent auditor in Proposal 3 and on all other matters in accordance with the recommendations of the Board.

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How to Vote

Shareholders of record can vote at the virtual Annual Meeting or by proxy without attending the Annual Meeting.

To vote by proxy:

If you hold your shares through a bank, broker or other holder of record, your bank, broker or other holder of record will provide you with materials and instructions for voting your shares. If you hold your shares through a bank, broker or other holder of record, and you plan to vote your shares at the Annual Meeting, you should complete the voting instructions form that the bank, broker or other holder of record provided to you or use the telephone or Internet voting options described on the voting instructions form or other materials that the bank, broker or other holder of record provided to you.

You will receive multiple Notices of Internet Availability or printed copies of the proxy materials if you hold your shares in different ways (e.g., individually, by joint tenancy, through a trust or custodial account, etc.) or in multiple accounts. Please vote the shares represented by each Notice of Internet Availability or proxy card you receive to ensure that all of your shares are voted.

Revoking Your Proxy

If you are a shareholder of record, you may revoke your proxy at any time before the shares are voted by proxy during the meeting. A shareholder may revoke a proxy by delivering written notice to the Secretary at or prior to the Annual Meeting or by timely delivery to the Secretary of a subsequently dated proxy card or by submitting a later vote by Internet or smartphone (instructions are on the Notice of Internet Availability or the proxy card). In the case of multiple submissions regarding the same shares, the proxy with the latest date will be counted. The address for the Secretary is c/o Trustmark Corporation, Post Office Box 291, Jackson, MS 39205.

If you hold your shares through a bank, broker or other holder of record, your ability to revoke your proxy depends on the voting procedures of the bank, broker or other holder of record. Please follow the directions provided to you by your bank, broker or other holder of record.

Voting on Other Matters

The Board is not aware of any additional matters to be brought before the meeting. If other matters do come before the meeting, the persons named in the accompanying proxy or their substitutes will vote the shares represented by such proxies in accordance with the recommendations of the Board.

CORPORATE GOVERNANCE

Overview

Trustmark's governance structure enables the Board to focus on value-added and forward-looking activities to effectively and efficiently address key, specific issues such as business growth, human capital, enterprise risk management, and technology, among others. This is accomplished through six standing Board committees and through the effective use of the directors' combined wisdom, diverse experience, and business knowledge.

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Key Features of Trustmark's Corporate Governance

Trustmark's governance structure has a number of key features that are designed to ensure effective and efficient oversight of the company, including the following:

The Code of Conduct for Trustmark Directors, Code of Ethics for Senior Financial Officers of Trustmark, Code of Ethics and Procedure to Report Violations of Law or Accounting or Audit Irregularities (Whistleblower Procedures) are available at investorrelations.trustmark.com or may be obtained, without charge, by written request addressed to the Secretary, Trustmark Corporation, Post Office Box 291, Jackson, MS 39205. Trustmark intends to provide required disclosure of any amendment to or waiver of its codes of conduct/ethics that applies to the chief executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, at investorrelations.trustmark.com promptly following any such amendment or waiver. Trustmark may also elect to disclose any such amendment or waiver in a report on Form 8-Kfiled with the Securities and Exchange Commission (SEC). The information contained on or connected to Trustmark's website is not incorporated by reference in this proxy statement and should not be considered part of this or any other document that Trustmark files with the SEC.

Meetings of the Board of Directors

The Board met six times in 2025. Each director attended at least 80% of the total number of meetings of the Board and Board committees of which the director was a member in 2025. The Board meets jointly with the Board of Directors of Trustmark Bank (the Bank Board), and since 2017, all members of the Board have also served as members of the Bank Board.

Director Attendance at the Annual Meeting

Directors are expected to attend the Annual Meeting, and in 2025, all Directors were present at the annual meeting of shareholders.

Director Independence

The Board determined in January 2026 that the following current directors and director nominees are "independent directors" (within the meaning of Rule 5605(a)(2) of the Nasdaq Listing Rules):

In conjunction with these independence determinations, the Board considered certain ordinary course customer relationships, including through family members and business affiliates, that Messrs. Baker, Host, Puckett, Yates and Dr. Hays have, and that former director William A. Brown had, with the wealth management and trust services division of the Bank. The Board also noted that a number of directors, including through business affiliates, have customer relationships with the Bank in the form of

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routine deposit, credit card and/or loan products in the ordinary course of business. In each case, the Board concluded that the business relationship did not interfere with the individual's ability to exercise independent judgment as a director of Trustmark.

In 2025 and prior years, the Board did not determine that Mr. Host and Mr. Yates were independent directors. However, with respect to Mr. Host, the Board took note of the fact that Mr. Host has not served as CEO since December 2020, and has not served as an employee of Trustmark in any capacity since April 2022. The Board also noted that Mr. Host has been non-executiveChair of the Board since April 2022 and, in that role, has interacted with Trustmark management in a fashion commensurate with the oversight role of a director. Further, the Board considered whether there were any personal, financial or other relationships between Mr. Host (or his family) and Trustmark and/or its officers or directors. On the basis of such review, the Board unanimously (with the exception of Messrs. Host and Yates, who did not participate) determined that Mr. Host has no relationship that would interfere with his exercise of independent judgment in carrying out the responsibilities of a director.

With respect to Mr. Yates, the Board considered the existence of certain transactions between Trustmark and entities in which Mr. Yates is an executive officer or otherwise has a controlling interest, including the transactions described under "Related Party Transactions" on page 46. The Board took note of the fact that neither Mr. Yates nor any of his family members has been or is a partner in, or a controlling shareholder or executive officer of, any organization to which Trustmark made, or from which Trustmark received, payments for property or services in any of the current or past three years exceeding the greater of $200,000 or 5% of the recipient's consolidated gross revenues for the year in question. Further, the Board considered whether there were any personal, financial or other relationships (beyond those noted above) between Mr. Yates (or his family or entities controlled by him) and Trustmark and/or its officers or directors. On the basis of such review, the Board unanimously (with the exception of Messrs. Yates and Host, who did not participate) determined that Mr. Yates has no relationship that would interfere with his exercise of independent judgment in carrying out the responsibilities of a director.

The Board has determined that Mr. Dewey is not an independent director.

Board Leadership

Under Trustmark's governance guidelines, which are contained in the Board Charter, the Board has the responsibility to determine the most appropriate leadership structure for the company, including whether it is best for the company at a given point in time for the roles of Board Chair and CEO to be separate or combined. Trustmark has had separate CEO and Board Chair roles since January 1, 2021, when Mr. Dewey was appointed CEO of Trustmark and the Bank. Mr. Host served as Executive Chairman of Trustmark and the Bank from January 2021 until April 2022, and has served as non-executiveBoard Chair since then.

Trustmark's bylaws provide that a non-executivedirector shall serve as Chair of the Executive Committee and the Nominating & Governance Committee if the positions of Chair of the Board and CEO are held by the same person or if the Chair of the Board is not otherwise independent. Further, Trustmark's Board Charter provides that when the Board Chair is also the CEO, or otherwise is not independent, or when, and for so long as, a majority of the independent directors determines that it is otherwise appropriate and in the best interests of Trustmark, a Lead Director shall be appointed who shall also serve as the Chair of the Executive Committee and Nominating & Governance Committee. Mr. Puckett has served as Lead Director, Chair of the Executive Committee, and Chair of the Nominating & Governance Committee since the 2020 annual meeting of shareholders, and continues to serve in those roles.

The Lead Director's responsibilities include (i) chairing meetings and executive sessions of the independent directors, Executive Committee, Nominating & Governance Committee and meetings on matters for which the Board Chair recuses himself and other meetings in the Board Chair's absence, (ii) coordinating with the Board Chair to develop Board meeting agendas and schedules, (iii) communicating with and advising the Board Chair, (iv) referring to the appropriate Board committee any issue brought to his attention by shareholders, directors or others, (v) serving as the primary communicator between the independent directors and the CEO and (vi) providing an alternative communication channel for all directors. The Board believes an independent Lead Director serves an important function in providing independent leadership of the Board and strengthening the Board's oversight of Trustmark's business. The Board Charter is posted at investorrelations.trustmark.com.

Committees of the Board of Directors

There are six standing Board committees: Audit, Enterprise Risk, Executive, Finance, Human Resources and Nominating & Governance. Each of these Board committees are joint committees of the Board and the Bank Board. The Audit, Enterprise Risk, Finance, Human Resources and Nominating & Governance Committees are comprised solely of independent directors and otherwise satisfy the requirements applicable to such committees under Nasdaq listing standards.

Audit Committee

The Audit Committee meets regularly throughout the year, including meeting with the external and internal auditors without management present. All members of the Committee are independent directors as defined by Nasdaq Listing Rules. The Committee's responsibilities include:

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The purpose and responsibilities of the Audit Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

Enterprise Risk Committee

The Enterprise Risk Committee is responsible for ensuring that Trustmark has policies and processes to identify and manage various risks throughout the company. All members of the Committee are independent directors as defined by Nasdaq Listing Rules. The Committee's responsibilities include:

The purpose and responsibilities of the Enterprise Risk Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

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Executive Committee

The Executive Committee acts on behalf of the Board if a matter requires Board action between regularly scheduled Board meetings. It also evaluates and makes recommendations to the Board regarding material corporate transactions.

The purpose and responsibilities of the Executive Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

Finance Committee

The Finance Committee is responsible for overseeing Trustmark's budgeting, capital planning and related financial strategy. The Committee's responsibilities include:

The purpose and responsibilities of the Finance Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

Human Resources Committee

The Human Resources Committee is responsible for overseeing the development of a program to compensate Trustmark's management in accordance with Trustmark's compensation philosophy and objectives. The Committee also ensures that appropriate policies and practices are in place to facilitate the development of associate and management talent. All members of the Committee during 2025 were and currently are "non-employeedirectors" within the meaning of Rule 16b-3under the Securities Exchange Act of 1934 (the Exchange Act), "outside directors" within the meaning of Section 162(m) of the Internal Revenue Code of 1986, as amended, and "independent directors" within the meaning of Rule 5605(a)(2) of the Nasdaq Listing Rules.

In fulfilling its role, the Committee's responsibilities include:

The purpose and responsibilities of the Human Resources Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

Nominating & Governance Committee

The purpose of the Nominating & Governance Committee is to assist the Board in recommending qualified individuals for election or re-electionto the Board and for assignment to Board committees, and to provide guidance on Board and corporate governance issues, as well as recommending orderly CEO succession. The Committee also evaluates the annual performance of the Board and its committees. All members of the Committee are independent directors as defined by Nasdaq Listing Rules. In fulfilling its role, the Committee's responsibilities include:

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The purpose and responsibilities of the Nominating & Governance Committee are described in greater detail in its Charter, which is posted at investorrelations.trustmark.com.

Board Oversight of Risk Management

Trustmark believes that its governance and leadership structures allow the Board to provide effective risk oversight. In addition to the reports from the Enterprise Risk Committee, Trustmark's directors receive and discuss regular reports prepared by Trustmark's senior management, including the Chief Financial Officer, Chief Credit and Operations Officer, Chief Administrative Officer, Chief Risk Officer and Chief Audit Executive. Through these reports, Trustmark's directors receive information on areas of material risks to the company, including credit, liquidity, market/interest rate, compliance, operational, and strategic risks. These reports enable Trustmark's directors to understand the risk identification, risk management and risk mitigation strategies employed by Trustmark's management and the Enterprise Risk Committee.

The Board and the Enterprise Risk Committee will request supplemental reports from Trustmark's management with regard to risk management and risk mitigation strategies as appropriate. This reporting and governance structure ensures that information from the Enterprise Risk Committee, the other committees of the Board and the Bank Board, and management is analyzed and reported to the Board, and enables the Board and its committees to coordinate the risk oversight role, particularly with respect to risk interrelationships.

The Board has ultimate oversight of cybersecurity-related risks and it is assisted in this role by the Enterprise Risk Committee and the Audit Committee. The Enterprise Risk Committee has primary oversight responsibility over management's efforts to manage and mitigate cybersecurity-related risk and reviews and approves Trustmark's cybersecurity strategy for protecting Trustmark's information assets and technology platforms. The Audit Committee oversees Trustmark's Internal Audit Department, which conducts reviews and assessments related to information security. Management provides periodic reports to the Enterprise Risk Committee and the Audit Committee, both of which provide reports of their meetings to the full Board. These reports to the Board and its Committees address the threat environment, vulnerability assessments, specific cyber incidents and management's efforts to monitor, detect and prevent cyber threats.

Committee Membership

The following table shows, for 2025, the membership of each committee and the number of meetings held by each committee during the year:

Communications with Directors

Shareholders desiring to contact Trustmark's Board may do so by sending written correspondence to Board of Directors, Trustmark Corporation, Post Office Box 291, Jackson, MS 39205 or by email addressed to [email protected].

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Communications will be referred to the Chair of the Nominating & Governance Committee, who will determine the appropriate committee to receive the communication and take any action deemed necessary by that committee.

Pursuant to Trustmark's Whistleblower Procedures, any violations of law or complaints or concerns regarding accounting or auditing matters should be reported to (i) Trustmark's independent online reporting center at www.trustmark.ethicspoint.com, (ii) Trustmark's independent hotline at 1-866-979-3769,or (iii) Trustmark's Ethics Committee Chair at 601-208-6867.Complaints will be investigated by Trustmark's Chief Administrative Officer and Chief Audit Executive and reported to the Audit Committee.

Nomination of Directors

Nominations for election to the Board may be made by or on behalf of the Board or by any shareholder of any outstanding class of capital stock of Trustmark entitled to vote in the election of directors at an annual meeting.

Nominations other than those made by or on behalf of the Board must be made in accordance with procedures set forth in Trustmark's bylaws. These procedures require that such nominations be in writing and that they be delivered or mailed to Trustmark's Chair of the Board and received (a) not less than 60 days nor more than 90 days prior to the first anniversary of the mailing date of Trustmark's proxy statement in connection with the last annual meeting of shareholders, or (b) if no annual meeting was held in the prior year or the date of the annual meeting has been changed by more than 30 days from the date of the prior year's annual meeting, not less than 90 days before the date of the annual meeting. The bylaws also require that such notification contain the following information to the extent known to the notifying shareholder: (a) the name and address of each proposed nominee, (b) the principal occupation of each proposed nominee, (c) the total number of shares of capital stock of Trustmark that will be voted for each proposed nominee, (d) the name and residence address of the notifying shareholder, (e) the number of shares of capital stock of Trustmark owned by the notifying shareholder, (f) such other information regarding such proposed nominee as would be required to be included in a proxy statement filed pursuant to the proxy rules of the SEC had the proposed nominee been nominated by the Board, (g) a representation that the notifying shareholder is the owner of shares entitled to vote at the meeting and intends to appear in person or by proxy at the meeting to nominate the proposed nominee, (h) the written consent of each proposed nominee to serve as a director of Trustmark if so elected and (i) a representation as to whether the notifying shareholder intends or is part of a group, which intends to solicit proxies or votes in support of such director nominees in accordance with Rule 14a-19under the Exchange Act. In addition, such notification must include the information required by Rule 14a-19(b)under the Exchange Act if the notifying shareholder intends to solicit proxies or votes in support of director nominees in accordance with Rule 14a-19under the Exchange Act.

Nominations not made in accordance with the above bylaw procedures may be disregarded by the Chair of the Board of the annual meeting at his discretion, and upon his instruction, all votes cast for each such nominee may be disregarded.

Trustmark's bylaws permit direct nominations by shareholders. Therefore, the Nominating & Governance Committee does not have a policy for considering nominations by shareholders other than through the bylaw process outlined above. However, if a shareholder wishes to recommend an individual for Board service, rather than directly nominate the individual as set forth above, the shareholder may submit the individual's name to the Nominating & Governance Committee by email to [email protected], or in writing addressed to Trustmark Corporation Nominating & Governance Committee, Post Office Box 291, Jackson, MS 39205. In order to give the Nominating & Governance Committee adequate time to consider any such individual for nomination as a director at the 2027 Annual Meeting of Shareholders, such recommendations should be delivered no later than October 1, 2026. In considering an individual recommended by a shareholder but not directly nominated, the Nominating & Governance Committee will use the same guidelines as set forth in the Director Qualifications section below.

When identifying potential candidates for director nominees, the Nominating & Governance Committee may solicit suggestions from incumbent directors, management or others.

Corporate Social Responsibility (CSR)

Trustmark believes that a company's commitment to corporate social responsibility is measured by its sustainability and societal impact. These factors are critical to long-term business viability. The company employs a Director of Corporate Social Responsibility and Community Development to monitor the continuing effectiveness of its program. Active community engagement, informed policies and procedures, and responsible philanthropy are some of the ways in which Trustmark continues to serve its communities and workforce.

Board Oversight. The Board has responsibility for overseeing Trustmark's strategies, policies, and programs relating to CSR matters, including community development and reinvestment activities, charitable giving, sustainability efforts, and other programs with social impacts. The Human Resources Committee reviews and approves Trustmark's policies and practices pertaining to workforce management issues.

CSR Engagement and Investment. The company's strategically aligned activities reflect its core values of Integrity, Service, Accountability, Relationships andSolutions. Trustmark's continued commitment to corporate social responsibility was demonstrated in 2025 through services provided to customers, partnerships formed in communities, and opportunities presented to associates. In 2025, Trustmark invested over $3.2 million in contributions and sponsorships to local organizations, including a $1.3 million tax credit investment allocated to 12 Mississippi youth and family-based charities providing services and programs for the welfare and development of children as part of Trustmark's involvement in the Mississippi Children's Promise Act.

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Trustmark's community contributions also included an investment of $339 thousand to Operation HOPE, Inc., a national non-profitorganization, to provide additional financial literacy support through the HOPE Inside Program within the designated markets of Memphis, Tennessee; Montgomery, Alabama; and Jackson, Mississippi. The program provides banking customers and members of the public with opportunities to receive financial tools and education to strengthen their financial security from within Trustmark branches through a dedicated financial wellness coach. The coaches conduct financial literacy seminars, individualized financial counseling sessions and provide referrals to disaster relief services. These services and resources are provided at no cost to community residents, which includes city employees and first responders. In 2025, more than 4,800 services were provided through Trustmark's partnership with Operation HOPE, Inc.

Trustmark continued to focus on financial education and community outreach with associates volunteering more than 7,200 hours of service to local partners through positions on non-profitboards of directors, financial literacy outreach and other forms of community engagement. The company also continued to partner with EVERFI, Inc., to provide online financial literacy courses in 54 schools throughout Mississippi, to educate approximately 5,700 students on financial matters through Trustmark's Financial Scholars Program. The company's partnership with EVERFI, Inc. also provides free online financial education through the Trustmark Financial Education Tool Kit, accessible at Trustmark.com. Trustmark also prioritizes partnerships that serve diverse communities and pursues opportunities to engage in that work.

Trustmark supports efforts to identify and reduce barriers to full, fair participation in the nation's banking system and the economy to help expand access to credit and capital. In 2025, Trustmark continued its partnership agreements with minority depository institutions Agility Bank in Houston, Texas and Commonwealth National Bank based in Mobile, Alabama.

In 2025, Trustmark leveraged its membership with the Federal Home Loan Bank of Dallas to award $883 thousand in grant funds to provide affordable housing support to income-qualified first-time homebuyers and eligible individuals with special needs. Trustmark's direct investments in low-to-moderateincome areas included $176.8 million in home mortgage loans, $429 million in small business loans and small farm loans and $222 million in community development loans. Trustmark also provided low-to-moderateincome borrowers with $269.9 million in home mortgage loans.

The company's collaborative work with community service providers, developers, realtors, housing advocates and others resulted in $45.6 million in investments that support and provide affordable housing, employment and community services for those with low-to-moderateincomes. Trustmark's community development entity and wholly-owned subsidiary, Southern Community Capital (SCC), was founded in 2012 to help guide work in this area by investing in projects in economically distressed areas through the New Markets Tax Credit (NMTC) program and the Low-IncomeHousing Tax Credit (LIHTC) Program. Additionally, Trustmark employs a dedicated team of associates to provide oversight of initiatives that advance financial growth and stability within racially and economically diverse communities. The Diverse Market Strategy Team coordinates with business units at Trustmark to develop innovative lending strategies, inclusive outreach events, targeted marketing campaigns, and special purpose products and programs to meet the unique needs of diverse communities throughout the company's footprint.

Human Capital and Workforce Diversity. Trustmark's commitment to serve diverse communities extends to its workforce practices. We are dedicated to fostering an inclusive environment where all individuals feel respected and valued. Trustmark's talent team continued to execute a recruitment strategy throughout the year, which included outreach to local and state agencies, campus recruitment at colleges and universities and holding employer advisory board memberships at local universities.

Sustainability. Throughout the year, Trustmark promoted sustainability through business practices that conserve natural resources and reduce energy consumption. Trustmark provides shredding services at all buildings and branch locations, offers enhanced digital banking options and processes for customers, and utilizes internal workflow management systems to reduce paper usage. The company previously completed a multi-year project to retrofit buildings with LED lighting to increase energy efficiency. The LED lighting project, as well as the installation of programmable thermostats and HVAC control systems have resulted in usage declines between 25-40 percent.In 2025, six additional projects were studied and completed, expanding this work. Trustmark's proactive business practices were reflected in the company's response to weather-induced events in 2025 through the activation of comprehensive disaster recovery and business continuity plans. The plans detail the responsibilities of key positions, instructions on ways to continue operations throughout the progression of weather-related events, and timeframes by which key tasks must be accomplished.

Additionally, Trustmark closely monitors security risks to its operations and takes proactive steps to safeguard against them. With those goals in mind, Trustmark has partnered with leading data center co-locationservice providers. This allows the company to operate its data center footprint with maximum scalability, resiliency, and security. These data center services also provide benefits including use of 100% renewable energy, net zero emissions, and net positive water projects.

Director Qualifications

The Board believes that in order to appropriately carry out its roles, directors must demonstrate a variety of personal traits, leadership qualities and individual competencies. In considering nominees submitted by the Board or management and any recommendations submitted by shareholders, the Nominating & Governance Committee will use these personal traits, leadership qualities and individual competencies to assess future director nominees' suitability for Board service. The Nominating & Governance Committee also evaluates each director nominee's qualities in the context of how that nominee would relate to the Board as a whole, in light of the Board's current composition and Trustmark's evolving needs.

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Personal Traits

Board service is an extremely important, high-profile role and carries with it significant responsibility. For that reason, it is important that all directors possess a certain set of personal traits, including:

Leadership Qualities

For individuals considered for Board leadership roles, the following skill sets are required:

Individual Competencies

There are certain competencies that must be represented collectively by the directors on each Board committee, but each individual director need not necessarily possess all of them. The specific competencies vary by committee, as illustrated in the chart below:

Specific Director Experience, Qualifications, Attributes and Skills

The Board believes that each person nominated for election at the Annual Meeting possesses the personal traits described above and that each director nominee who has served in a position of Board leadership also demonstrates the additional leadership qualities described above. In considering the director nominees' individual competencies, the Board believes that the appropriate competencies are represented for the Board as a whole and for each of the Board's committees. In addition, each nominee possesses characteristics that led the Board to conclude that such person should serve as a director. The specific experience, qualifications, attributes and skills that the Board believes each nominee possesses are discussed under Proposal 1 in the table entitled "The Nominees," beginning on page 13.

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Board Diversity

Although Trustmark has no formal policy regarding diversity, the Nominating & Governance Committee believes that the Board should include directors with diverse skills, experience and business knowledge, and whose backgrounds, ages, geographical representation and community involvement contribute to an overall diversity of perspective that enhances the quality of the Board's deliberations and decisions. The Nominating & Governance Committee may consider these factors as it deems appropriate in connection with the general qualifications of each director nominee.

Of the Board's 11 members, two are women and two are racially or ethnically diverse.

PROPOSAL 1: ELECTION OF DIRECTORS

The Board has fixed the number of directors for the coming year at 11.

The nominees listed herein have been proposed by the Board for election at the Annual Meeting. Shares represented by valid proxies will, unless authority to vote is withheld, be voted in favor of the proposed slate of 11 nominees. Directors must receive a majority of the votes cast in order to be elected (that is, the number of shares voted "for" a director must exceed the number of shares voted "against" that director). If a nominee who is an incumbent director is not elected to the Board, and no successor is elected, such nominee must tender his or her resignation to the Board. The Nominating & Governance Committee will then make a recommendation to the Board on whether to accept or reject the resignation or whether to take other action. The director who tenders his or her resignation may not participate in the recommendation of the Nominating & Governance Committee or the decision of the Board with respect to his or her resignation. Each director is elected to hold office until the next annual meeting of shareholders or until a successor is elected and qualified.

The Board recommends that shareholders vote "FOR" the proposed nominees.

The Nominees

Experience and qualifications: Mr. Baker is chairman and former chief executive officer of a publicly-traded company that is the largest producer and distributor of shell eggs in the United States. His position has provided him with significant business leadership skills and experience in evaluating strategic alternatives that focus on maximizing shareholder value. Mr. Baker's years of service as a director of the Bank, and particularly as the former chair of the Bank Board's Asset/Liability Committee (the responsibilities of which are now performed by the Finance Committee), provide him with an intrinsic understanding of Trustmark's strategy for managing liquidity, which is a skill essential to the Board's risk oversight function. He is a member of the National Association of Corporate Directors.

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Experience and qualifications:General Collins has served as the CEO of MINACT, Inc., a job training, development and management company, since 2016. He currently serves on the Audit and Cybersecurity Committees of Huntington Ingalls Industries, Inc., the largest military shipbuilding company in the United States, as well as a provider of professional services to partners in government and industry. General Collins retired with the rank of Major General in the Mississippi National Guard, having served as Adjutant General of both the Mississippi Army National Guard and the Mississippi Air National Guard from 2012 to 2016. His 35 years of combined military service in the U.S. Army and the Mississippi National Guard included the command of the 155th Brigade Combat Team in Iraq, where he was responsible for security operations in the southern and western provinces. He was previously appointed by the Governor to the Mississippi Workers' Compensation Commission where he served as the commission's representative of labor. General Collins' years of service and leadership provide him with valuable experience in human resources as well as strategic and financial planning, which qualifies him for service as one of the Board's audit committee financial experts. He is also experienced with operating in a regulatory environment and with regulatory bodies. General Collins is a member of the National Association of Corporate Directors.

Experience and qualifications:Ms. Conerly is a certified public accountant and a former certified valuation analyst. Her experience as a partner at a large certified public accounting firm has provided her with significant financial and accounting expertise, particularly in the areas of auditing, business valuation and tax, and qualifies her for service as one of the Board's audit committee financial experts. Ms. Conerly's years of service as a director of a publicly-traded financial institution provide her with valuable experience in financial institution governance and an understanding of markets that are a strategic focus for Trustmark. Ms. Conerly also served on the Bank Board's Asset/Liability Committee (the responsibilities of which are now performed by the Finance Committee), providing her with an understanding of Trustmark's balance sheet strategy, which is a skill essential to the Board's risk oversight function. She is a member of the National Association of Corporate Directors.

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Experience and qualifications: Mr. Dewey became president and chief executive officer of Trustmark and the Bank on January 1, 2021. He was formerly president and chief operating officer of the Bank from January 1, 2020, to December 31, 2020. He served as chief operating officer of the Bank from January 1, 2019, to December 31, 2019, and as President of Corporate Banking from 2008 to 2018. Mr. Dewey, with 22 years of experience at Trustmark and 40 years in the financial services industry, has worked in diverse geographic markets and in numerous lines of banking businesses. His executive management responsibilities in retail and institutional banking, mortgage, wealth management and insurance services enable him to provide valuable operational, strategic and financial perspectives to the Board. In addition, Mr. Dewey serves on the newly formed Mississippi Business Alliance Board of Directors as 2^nd Vice Chair and will become Chair in 2028. He previously served on the Mississippi Economic Council Operating Board and Board of Governors from 2021 to 2025, and as 2^nd Vice Chair from 2024 to 2025, and Treasurer of the Board from 2023 to 2024. In addition, Mr. Dewey serves on the Mississippi Partnership for Economic Development and served as Chair in 2025. Beginning January 1, 2026, Mr. Dewey became a member of the Federal Advisory Council representing the Sixth Federal Reserve District. Mr. Dewey is a member of the National Association of Corporate Directors.

Experience and qualifications: Mr. Eduardo has served as the Dean of the School of Business at a private college in Mississippi since 2000. He holds Ph.D. (Finance) and MBA degrees and serves as the Anderson Distinguished Professor of Finance at Mississippi College. Mr. Eduardo, an accomplished academic, has authored numerous articles on a variety of topics, including investment management, compliance, capital management and the pricing of retail banking services, which have been published in national and international journals. His expertise in banking and corporate finance, combined with his proven marketing and leadership skills, provide valuable marketing, strategic and financial perspectives to the Board, and qualifies him for service as one of the Board's audit committee financial experts. Mr. Eduardo also served as Chair of the Bank Board's Asset/Liability Committee (the responsibilities of which are now performed by the Finance Committee). He is a member of the National Association of Corporate Directors.

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Experience and qualifications: Dr. Hays is a cardiologist and partner of Jackson Heart Clinic, PA, one of the largest cardiology groups in Mississippi. He is a former chairman of the Mississippi Healthcare Solutions Institute and former director and past president of the Mississippi State Medical Association. He serves as director and secretary of the Medical Assurance Company of Mississippi, a statewide medical malpractice insurer. He is also a Mississippi Delegate to the American Medical Association House of Delegates and Chair of the Southeast Delegation of the AMA House of Delegates. With extensive experience in the medical industry, Dr. Hays is uniquely positioned to advise Trustmark on the healthcare industry and provide the Board with an important resource for assessing and managing risks. Dr. Hays also served on the Bank Board's Asset/Liability Committee (the responsibilities of which are now performed by the Finance Committee). He is a member of the National Association of Corporate Directors.

Experience and qualifications: Mr. Host has served as Chair of the Boards of Trustmark and the Bank since April 2022. He served as Executive Chairman of Trustmark and the Bank from January 1, 2021 to April 26, 2022. Mr. Host served as president and chief executive officer of Trustmark and chief executive officer of the Bank from January 1, 2011, to December 31, 2020, and served as president of the Bank from 2011 to December 31, 2019. He also served as a director of the Federal Reserve Bank of Atlanta from 2012 until the end of his second term on December 31, 2018. Throughout his 38-yeartenure with Trustmark, Mr. Host has served in a variety of executive management capacities, including chief financial officer, chief investment officer and president of various divisions. Mr. Host's in-depthknowledge of Trustmark's operations and of the financial services industry enables him to provide both historical and strategic perspectives in Board discussions regarding corporate strategy and governance matters. He is a member of the National Association of Corporate Directors.

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Experience and qualifications: Mr. Morrissette serves as the president of a regional packaged food and food services company based in Alabama. His prior years of service as a director of a publicly-traded financial institution provide him with valuable experience in financial institution governance and an understanding of markets that are a strategic focus for Trustmark. In addition, Mr. Morrissette's background and business acumen provide him with the skills necessary to contribute invaluable insight and broad perspectives to Board discussions. He also served on the Bank Board's Credit Policy Committee (the responsibilities of which are now performed by the Enterprise Risk Committee). Mr. Morrissette is a member of the National Association of Corporate Directors.

Experience and qualifications: Mr. Puckett is the chairman of a heavy equipment distribution and rental company with facilities located in Mississippi and eastern Louisiana that provide heavy equipment, engine power solutions and related supplies to a variety of industries. Mr. Puckett brings marketing and business leadership skills to the Board, as well as an in-depthunderstanding of the business climate and customer base in Trustmark's major legacy markets. His experience and Board tenure provide valuable perspective to the Board. He also served on the Bank Board's Credit Policy Committee (the responsibilities of which are now performed by the Enterprise Risk Committee). Mr. Puckett's in-depthknowledge of Trustmark's operations and of the financial services industry enables him to provide both historical and strategic perspectives in Board discussions regarding corporate strategy and governance matters. Mr. Puckett is a member of the National Association of Corporate Directors.

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Experience and qualifications:Ms. Turnipseed is a certified public accountant and has served since 2022 as Vice President and General Auditor for Entergy Corporation. Previously, she worked for Entergy Mississippi, LLC, serving as Vice President of Customer Service from 2018 to 2022, and Director, Finance from 2012 to 2018. Ms. Turnipseed serves on the newly formed Mississippi Business Alliance Foundation Board of Directors. She previously served on the Board of Governors of the Mississippi Economic Council from 2013 to 2025 and on the Operating Board of the Mississippi Economic Council from 2019 to 2025. Ms. Turnipseed previously served on the Board of Directors of the Mississippi Manufacturers Association from 2019 to 2022, and the Board of Trustees of the United Way of the Capital Area in Jackson, Mississippi from 2019 to 2022. She brings to the Board extensive financial and accounting expertise as well as experience in risk management and the regulated utility industry, and her extensive knowledge of the Mississippi economic environment provides the Board with valuable insight and qualifies her for service as one of the Board's audit committee financial experts. Ms. Turnipseed is a member of the National Association of Corporate Directors.

Experience and qualifications: Mr. Yates is the president and chief executive officer of a commercial construction company with operating divisions located throughout the Southeast, many of which are within markets served by Trustmark. Mr. Yates' knowledge of these markets, as well as his leadership experience in the various aspects of the construction industry, including employee relations matters, contract negotiations, and risk management, provide the Board with an important resource for assessing and managing risks and planning for corporate strategy. He formerly served as a member of the Bank Board's Asset/Liability Committee and Credit Policy Committee (the responsibilities of which are now performed by the Finance Committee and the Enterprise Risk Committee, respectively). In January 2021, Mr. Yates was appointed a director of the Federal Reserve Bank of Atlanta, New Orleans Branch. In addition, Mr. Yates serves on the newly formed Mississippi Business Alliance Board of Directors. He previously served on the Mississippi Economic Council Board of Directors from 2011 to 2025, including as a former chairman. Mr. Yates also serves on the Mississippi Partnership for Economic Development Board of Directors. He is a member of the National Association of Corporate Directors.

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EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

This Compensation Discussion & Analysis (CD&A) explains our executive compensation program for our named executive officers (NEOs), listed below. This CD&A also describes the process of the Human Resources Committee of the Board (the Committee) for making pay decisions, as well as its rationale for specific decisions related to the fiscal year ended December 31, 2025.

Executive Summary

Trustmark is committed to aligning the compensation of its executive officers with Trustmark's financial and operational performance. The Committee believes that its current executive compensation program is helping to achieve these goals by aligning compensation with Trustmark's performance.

2025 Business Highlights.Trustmark's momentum continued to build throughout the year, resulting in record earnings in 2025. Our traditional banking business drove continued loan and deposit growth, a strong net interest margin, and solid credit quality. Our mortgage banking business achieved increased production and significant improvement in profitability while revenue in our wealth management business reached an all-timehigh.

For more information on return on average tangible equity and tangible book value per share, which are non-GAAPfinancial measures, including a reconciliation of such measures to amounts reported under GAAP, please see the section entitled "Non-GAAPFinancial Measures" in Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations in Trustmark's 2025 Form 10-K.

2025 Executive Compensation Highlights.Our executive compensation program has three primary elements: base salary, annual incentives under our Annual Management Incentive Plan (MIP), and long-term equity incentives under the Trustmark Corporation Stock and Incentive Compensation Plan (Trustmark Stock Plan). Each of these compensation elements serves a specific purpose in our compensation strategy. Base salary is an essential component to any market-competitive compensation program. Annual incentives reward the achievement of short-term goals, while long-term equity incentives drive our NEOs to focus on long-term sustainable stockholder value creation. The following executive compensation actions for 2025 are aligned with Trustmark's financial performance and are consistent with the design of Trustmark's program:

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Best Compensation Practices & Policies.The following practices and policies within our program promote sound compensation governance and are in the best interests of our stockholders and executives:

2025 Say on Pay Vote. Each year, we carefully consider the results of our shareholder say-on-payvote from the preceding year. In 2025, the advisory shareholder vote on Trustmark's executive compensation received approval of over 98.9% of the votes cast on the proposal. In light of such strong support, we did not make any material changes to our program for 2025.

What Guides Our Program

Guiding Philosophy. The guiding philosophy of the Committee is to attract and retain highly qualified executives and to motivate them to maximize shareholder value while managing risk appropriately and maintaining the safety and soundness of the organization. The Committee believes that a significant portion of an executive's total compensation should be variable and dependent upon the attainment of certain specific and measurable annual and long-term performance objectives, and aligned with the interests of Trustmark's shareholders. The Committee also believes that executive compensation should be competitive, allowing Trustmark to recruit, retain and motivate executives who play a significant role in the organization's current and future success. Further, compensation policies and practices should be designed to help develop management talent, promote teamwork and reinforce effective corporate governance.

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Compensation Mix.While the Committee considers the overall mix of executives' pay between base salary, annual cash bonus and long-term incentive compensation, the Committee does not target a specific allocation among the various compensation components. Generally, more than one-halfof the CEO's compensation is contingent on performance, and approximately one-halfof the compensation provided to the other NEOs is contingent on performance. In allocating compensation among salary, bonus and equity-based compensation, the Committee believes that the compensation of the senior-most levels of management with the greatest ability to influence Trustmark's performance should be significantly performance-based, while lower levels of management should receive a greater portion of their compensation in base salary. The Committee also makes allocations between short-term and long-term compensation for NEOs. Consistent with its executive compensation philosophy and goals, in 2025, the Committee provided that for the senior-most levels of management 100% of annual cash incentive payments and 50% of long-term equity-based awards would be determined based on achievement of performance targets.

The charts below show the target annual total direct compensation of our CEO and our other NEOs for fiscal year 2025. These charts illustrate that a majority of target annual total direct compensation is variable (66% for our CEO and an average of 56% for our other NEOs). These charts do not include any one-timeequity grants or awards outside of target annual total direct compensation.

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The Decision-Making Process

The Role of the Committee. The Committee oversees the executive compensation program for our NEOs. The Committee is comprised of independent, non-employeemembers of the Board. The Committee works closely with its independent consultant and management to examine the effectiveness of the Company's executive compensation program throughout the year. The Committee reviews all of the components of compensation in making determinations on the mix, amount and form of executive compensation. In making compensation decisions, the Committee seeks to promote teamwork among, and high morale within, executive management, including the NEOs. While the Committee does not use any quantitative formula or multiple for comparing or establishing compensation for executive management, it is mindful of internal pay equity considerations and assesses the relationship of the compensation of each executive to other members of executive management. The Committee makes all recommendations for compensation and equity award decisions regarding our NEOs, including the CEO, for final approval by the independent members of the full Board.

Details of the Committee's authority and responsibilities are specified in the Human Resources Committee Charter, which is posted at investorrelations.trustmark.com.

The Role of Management. The Chair of the Committee works with the CEO and the Human Resources department to establish the agenda for Committee meetings. The CEO and Human Resources department also interface with the Committee in connection with the Committee's executive compensation decision-making, providing comparative market data as well as making recommendations. The Committee periodically meets with the CEO and members of the Human Resources department to assess progress toward meeting objectives set by the Board for both annual and long-term compensation. The Committee also meets in executive session without management present when appropriate.

The Role of the Independent Compensation Consultant. The Committee engages an independent compensation consultant to provide expertise on competitive pay practices, program design, and an objective assessment of executive and non-employeedirector compensation programs. Pursuant to authority granted to it under its Charter, the Committee has hired Pearl Meyer as its independent consultant. Pearl Meyer reports directly to the Committee and does not provide any additional services to management. The Committee has assessed the independence of Pearl Meyer pursuant to SEC and Nasdaq rules and has concluded that the advice it receives from Pearl Meyer is objective and not influenced by other relationships that could be viewed as conflicts of interest.

With respect to Trustmark's compensation program for executives and non-employeedirectors for 2025, the Committee depended on Pearl Meyer's current and previous services including:

Benchmarking. We believe competitive compensation is essential for attracting and retaining top executives. The Committee ensures our pay practices align with organizations with whom we compete for executive talent and are similar in size and scope.

For purposes of setting compensation levels for 2025, the Committee reviewed peer group data and survey data to establish a competitive pay range for our NEOs. For each NEO, the Committee recommends salary, annual incentives, and long-term incentives, using market data as a reference but also considering individual experience, performance, responsibilities, and contributions. For the CEO, the Committee follows a similar process of reviewing peer group data and survey data in order to recommend the appropriate mix and level of compensation elements to the full Board, with final approval by independent Board members. Although the Committee and the Board do not set compensation levels for our NEOs solely on peer group data and survey data, as a general matter they believe it is appropriate for our NEOs' total direct compensation to be competitive in alignment to applicable peer group and market standing for comparable positions.

Our peer group data is sourced from proxy statements of financial institutions and updated annually. These institutions are chosen for their similarity in size, business mix, and relevance for executive talent and shareholder competition. The peer group focuses on institutions with at least $10 billion in assets, because these institutions are subject to the same regulatory mandates as Trustmark. The 2025 compensation peer group listed below included 21 companies with assets ranging from $12.0 billion to $35.2 billion (65% to 191% of our asset size) and market capitalizations between $1.5 billion and $6.6 billion.

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For 2025, Trustmark's peer group consisted of the following companies:

2025 Executive Compensation Program in Detail

Base Salaries.Base salary represents annual fixed compensation and is a standard element of compensation necessary to attract and retain executive leadership talent.

In establishing the CEO's base salary, the Committee considers peer group and market data provided by its independent compensation consultant, as well as internal data provided by Human Resources. The Committee also takes into account the CEO's individual performance and contributions relative to Trustmark's corporate goals. In establishing base salaries of the other NEOs, the Committee considers the recommendations of the CEO, which are based on individual responsibility level, individual and company performance, total compensation histories for each such NEO, as well as peer group and market data provided by its independent compensation consultant. The Committee also evaluates each NEO's overall span of responsibility and control, knowledge and leadership ability.

Based on its review and upon the Committee's recommendation, the Board approved base salary increases of 6.7% for Mr. Dewey and 13.4% for Mr. Owens. The Bank Board approved base salary increases of 4.0% for Mr. Stevens and 3.0% for Messrs. Harvey and Tate, in each case effective as of July 1, 2025. The comparatively larger increases in base salary for Mr. Dewey and Mr. Owens for 2025 reflects the Committee's and Board's desire to more closely align their salaries to comparable positions within the applicable peer group and market positioning, which is consistent with the Committee's guiding philosophy for executive compensation to be competitive.

The base salaries in effect during 2024 and 2025 are shown below:

Annual Management Incentive Plan (MIP).The Committee typically awards annual cash incentives utilizing a structured, objective approach based upon the achievement of performance objectives set forth in an annual management incentive plan. Cash incentives constitute the largest cash component tied specifically to company performance. The 2025 MIP provided our NEOs the opportunity to earn a performance-based annual cash incentive award. Target award opportunities are expressed as a percentage of base salary and are established based on the NEO's level of responsibility and ability to impact the Company's overall results. The Committee also considers market data in setting target award amounts. Actual incentive award payouts depend on the achievement of pre-determinedcorporate financial, strategic/operational and, where applicable, line of business (LOB) objectives. The selected performance goals are intended to be challenging, but achievable for results at or slightly above the established target levels. Actual payouts can range from 0% to 200% of target award amounts. Annual MIP awards for executives are subject to the terms of Trustmark's executive compensation clawback policy (the Clawback Policy) as such may be in effect from time to time, as well as any similar provisions of applicable law, which could in certain circumstances require repayment or forfeiture of incentives received with respect to the MIP awards.

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2025 Target Award Opportunity. The Committee increased Mr. Dewey's target annual opportunity from 80% in 2024 to 90% in 2025 and Mr. Stevens' from 50% in 2024 to 60% in 2025, to better align with the market. All other NEO target annual award opportunities remained unchanged from 2024. As a result, NEO target award opportunities for 2025 were as follows:

2025 Performance Objectives, Metrics, Weightings and Results.The performance objectives and metrics upon which our NEOs' MIP awards are determined and approved by the Committee at the beginning of each year are directly linked to the key drivers of our business. Depending on achievement against the stated performance metrics, actual awards, if any, for 2025 could range from 50% of the target award payout (for threshold performance achievement) to 100% (for target performance achievement) to 200% (for maximum performance achievement). If performance is below threshold level for each of an NEO's objectives under the MIP, no award is earned. Payouts are linearly interpolated for performance between threshold and maximum.

For 2025, the MIP was focused on driving profitability and operational efficiency. Specifically, by weighting corporate EPS and Efficiency Ratio more heavily, the MIP encourages sustainable financial performance while ensuring the Company operates cost-effectively. This combination promotes both growth in earnings and a disciplined approach to managing expenses. In addition, the Committee approved separate expense metrics for corporate functions and individual LOBs to balance responsibility for managing costs across teams and individuals. For 2025, the threshold and maximum performance levels continue to reflect the uncertainty of achieving the goals and provide variability in pay for changes in performance while also requiring higher performance to reach the maximum payout level.

After the target levels and performance goals and weightings have been approved by the Board, the Committee retains the discretion to adjust the target levels and performance goals and weightings during the year, on an individual or group basis, if the Committee determines additional adjustments are appropriate for this purpose.

The table below summarizes the corporate financial, strategic/operational performance metrics, weights, achievement goals, and actual results for the CEO for:

The other NEOs' performance is measured using the same corporate financial, strategic/operational performance metrics as shown in the table above for the CEO, except that Core Adjusted Non-InterestExpense is measured both at the Corporate level and for each other NEO's LOB, each weighted at 10%. The 10% weighting for LOB Non-InterestExpense resulted in differing levels of overall achievement for the other NEOs, depending on the results achieved by each other NEO's LOB.

At year end, the Committee, at its discretion, also reserves the right to adjust any MIP award payments proposed for a NEO. The Committee's exercise of discretion is intended to ensure the MIP appropriately rewards performance and prevents unintended windfalls or penalization to participants. The Committee did not make any such adjustments for 2025.

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2025 Target Award Opportunity. In determining the size of each equity award granted, the Committee considers a variety of factors, including market value, and internal equity. The table below shows the target annual LTI award values granted for 2025 for each of the NEOs:

* Actual award amounts for PSUs and RSUs at target levels were determined based on the average of the closing price of Company common stock for the 10 days leading up to grant date which was on February 12, 2025. The 10-dayaverage (1/30/2025 - 2/12/2025) closing stock price was $37.91.

The grant date fair value of the PSUs and RSUs granted in 2025 are shown in the "Grants of Plan-Based Awards for 2025" table on page 32.

A Closer Look at PSUs.For PSUs granted in 2025, the performance period began January 1, 2025, and continues through December 31, 2027. Consistent with past years, PSUs vest based on the achievement of Company performance goals related to ROATE and TSR over a three-year period.

Actual award payouts can range from 0% to 200% of target for the three-year performance cycle depending on overall performance achievement results. The ROATE and TSR results are combined to determine the overall achievement. Award payouts are linearly interpolated for performance between threshold and maximum. No awards are earned below the threshold performance level.

Performance Awards Earned (2023-2025 Performance Period).For the 2023-2025 performance period, the NEOs earned 165.0% of their target PSUs based on Trustmark's three-year average ROATE compared to an absolute target and TSR, which includes dividends, performance relative to Trustmark's peer group, as shown in the table below.

Other Compensation Practices, Policies & Guidelines

Stock Ownership Guidelines.To help mitigate risks associated with Trustmark's compensation programs and encourage management to focus on long-term growth and financial success, Trustmark has guidelines that require the CEO and other members of executive management of the Bank to own, at minimum, the number of shares of Trustmark stock equal in value to a multiple of their base salary.

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The guidelines as of July 1, 2025 are as follows:

The guidelines calculate the number of shares to be owned by reference to an executive's base salary as of July 1 of each year and the 10-daytrading average share price through June 30 each year. Unvested time-based restricted stock units are counted as shares owned for purposes of the guidelines. Pledged shares are not considered to be owned for purposes of the stock ownership guidelines. The Committee reviews stock ownership levels of executive management annually. Until an executive has reached the applicable ownership level, the executive is required to hold 100% of the shares received from any Trustmark stock awards. Based on the most recent review of ownership level attainment in 2025, all of the NEOs owned the minimum number of shares required to satisfy the guidelines.

Executive Compensation Recoupment.The Committee includes clawback provisions in LTI awards and the MIP, which generally provide that any such award that vests or cash bonus paid is subject to recovery by Trustmark as required by applicable federal law and/or such basis as the Board determines. On October 24, 2023, the Board adopted the Clawback Policy consistent with the requirements of Rule 10D-1under the Exchange Act and Nasdaq listing standards. The Clawback Policy provides that, in the event Trustmark is required to prepare an accounting restatement of its financial statements due to Trustmark's material noncompliance with any financial reporting requirement, executive officers covered by the Clawback Policy must reimburse Trustmark, or forfeit, any excess incentive compensation received by such covered executive officer during the three completed fiscal years immediately preceding the date on which Trustmark is required to prepare the restatement. Incentive compensation subject to the Clawback Policy includes any cash or equity compensation that is granted, earned or vested based wholly or in part on the attainment of a financial reporting measure. The amount subject to recovery is the excess of the incentive compensation received based on the erroneous data over the incentive compensation that would have been received had it been based on the restated results.

Policy Against Hedging and Limitations on Pledging. To ensure that Trustmark directors, officers and employees bear the full risks of stock ownership, Trustmark's Insider Trading Policy prohibits Trustmark directors, officers and employees from engaging in any form of hedging transactions relating to Trustmark stock. With limited exceptions, directors and executive officers are also prohibited from pledging or creating a security interest in any Trustmark stock they hold, and no director or executive officer currently holds any Trustmark stock that is pledged or otherwise subject to a security interest.

Retirement Benefits. Trustmark maintains certain plans providing retirement benefits in which the NEOs and certain other associates participate, as described below.

Executive Deferral Plan.Because of the limits for tax qualified retirement plans, Trustmark maintains a defined benefit supplemental retirement plan (Executive Deferral Plan) that provides additional retirement benefits to selected executives. While the Committee believes that the plan provided a competitive element and was a traditional component among peer financial institutions as a tool for retaining executive management, the Committee has not recommended adding new participants to the plan since 2008. As a result, Mr. Tate and Mr. Owens, who joined the company after that time, are not participants.

NEOs selected for plan participation by the Committee receive retirement benefits generally equal to 50% of their covered salaries. The retirement benefit is payable for life, but not less than ten years, and commences at normal retirement age, which is 65, whether or not the participant is still employed, unless the early retirement or death provisions described below apply. Benefits payable pursuant to the plan are not subject to reduction for social security benefits.

The plan provides retirement and pre-retirementdeath benefits based upon a retirement benefit amount for each participant established by the Committee. The retirement benefit amount is based on the participant's specified covered salary.

The following table shows, as to each NEO, annual retirement benefits anticipated to be paid at normal retirement:

In 2023, Mr. Dewey, and in 2025, Mr. Harvey, became eligible for payments under the Executive Deferral Plan. However, the plan provides that payments shall be delayed if such payments would not be deductible under Section 162(m) of the Internal Revenue Code. As a result, payments to Mr. Dewey for 2023 through 2025 were delayed, and payments to Mr. Harvey for 2025 were delayed.

See the "Pension Benefits for 2025" table on page 34 for more information regarding this plan.

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Non-QualifiedDeferred Compensation Plan.  Trustmark also provides a Non-QualifiedDeferred Compensation Plan (the NQDC Plan) that provides additional cash compensation deferral opportunities for executives who are impacted by the compensation and contribution limits that restrict participation in Trustmark's 401(k) plan. The Committee believes the plan is competitive with those offered by Trustmark's peer financial institutions and is an important tool in attracting and retaining executive management. The plan allows executives, including NEOs, to defer on a pre-taxbasis up to 90% of annual base salary and/or cash bonus. The NQDC Plan permits discretionary contributions by Trustmark, and in March 2026 Trustmark contributed an aggregate amount of $155,000 to the CEO's and other NEOs' accounts. The contributions made in March 2026 in respect of 2025 performance were dependent on reaching Trustmark's performance threshold of 95% of the established EPS target for 2025. Each executive's deferred income is credited to an account, which is deemed invested in and mirrors the performance of one or more designated investment funds available under the plan and selected at the option of the executive. Distributions can be received under this plan upon retirement, death, long-term disability, termination of employment or during employment at specified dates.

In 2021, 2022, 2023 and 2024, Mr. Dewey had a scheduled distribution from the NQDC Plan. However, the plan provides that any distribution shall be delayed if such distribution would not be deductible under Section 162(m) of the Internal Revenue Code. As a result, the scheduled distributions to Mr. Dewey for such years were delayed.

See the "Non-QualifiedDeferred Compensation for 2025" table on page 35 for more information regarding this plan and see the "Summary Compensation Table for 2025" on page 30 and the "All Other Compensation for 2025" table on page 31 for more information regarding Trustmark's contribution to Trustmark's 401(k) Plan.

Perquisites; Other Benefits.  Perquisites provided to executive officers are reviewed annually within the context of Trustmark's executive compensation program, market practices and the nature of each executive's responsibilities. Generally, Trustmark limits the types of perquisites offered to executive officers as shown in the "All Other Compensation for 2025" table on page 31.

The Committee believes the currently-offered perquisites are minimal in overall cost and competitively necessary to attract and retain talented executives. Consistent with most other financial institutions in its peer group, Trustmark encourages executive management to belong to a golf or social club so that there is an appropriate entertainment forum for customers and appropriate interaction with the executives' communities. Trustmark pays the initiation fee and annual dues for a club membership for some of the NEOs. In addition, Trustmark provides Messrs. Dewey and Stevens with use of a company-owned automobile. In addition, the Board authorizes an annual allowance of up to 15 hours of personal use of Trustmark's airplane for the CEO, which provides an efficient way to maximize the CEO's available time for company business.

Severance and Change in Control Benefits.  Upon any termination of employment, NEOs would be entitled to receive their vested benefits under the 401(k) plan, NQDC Plan and supplemental retirement plan (Executive Deferral Plan), although these benefits generally would not be increased or accelerated (except for the acceleration of additional years of service provided under the Executive Deferral Plan under certain circumstances).

Trustmark believes that additional severance benefits are appropriate for executive management because it may be difficult for senior executives to find comparable employment within a short period of time. As discussed above, Trustmark's restricted stock and restricted stock unit awards provide for accelerated vesting in the event of a "double trigger" change in control and upon certain termination events, and an incremental benefit is provided under the Executive Deferral Plan upon certain termination events following a change in control.

In light of the CEO's and other NEOs' role and importance to the success of Trustmark, the Committee believes that it is appropriate to provide for severance and change in control benefits in written agreements. The Committee further believes that providing change in control benefits to the CEO and other NEOs should eliminate any reluctance to pursue potential change in control transactions that may be in the best interests of shareholders. Trustmark also believes that the severance and change in control benefits it provides are customary among its peers.

Trustmark's change in control benefits provided to the CEO and other NEOs are "double trigger," which means that the benefits are payable only if the executive's employment is terminated other than for cause, death or disability or if the executive resigns for good reason, in each case within a specified period following a change in control. Trustmark believes that these benefits are consistent with the general practice among its peers. In addition, Trustmark believes the use of a double trigger in most cases reasonably balances the needs of the executive and Trustmark by protecting the legitimate interests of executives in employment security without unduly burdening Trustmark or shareholder value. Beginning in 2024, all new restricted stock unit awards granted are "double trigger".

Trustmark does not provide any tax gross-upsrelated to severance or other compensation or benefits that executives may receive in connection with a change in control. Change in control benefits are provided on a "best net" approach, under which an executive's change in control benefits are reduced to avoid the golden parachute excise tax only if such a reduction would cause the executive to receive more after-taxcompensation than without a reduction.

For additional information on Trustmark's employment and change in control agreements with its NEOs, please see "Employment and Change in Control Agreements with NEOs" beginning on page 41.

Analysis of Risk Associated with Trustmark's Compensation Policies and Practices. In late 2025 and early 2026, the Committee, together with Trustmark's risk, compliance and human resources officers, and line of business management, conducted an in-depthrisk assessment of Trustmark's compensation policies and practices. Management prepared detailed materials regarding the operation of Trustmark's various compensation arrangements with its associates and submitted the

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materials to Trustmark's risk and compliance officers, who with human resources officers reviewed the materials with the members of management most closely involved with the respective compensation arrangements. Risk and compliance provided credible challenge of the risk assessments, and the final inherent risk, control, and residual risk ratings were discussed with the line of business management. Trustmark's Chief Risk Officer and Director of Human Resources presented the officers' conclusions and supporting materials to the Committee, which reviewed and discussed the analysis at its meeting on February 17, 2026.

The Committee has concluded that Trustmark's compensation policies and practices have sufficient mitigating features and controls to maintain an appropriate balance between prudent business risk and resulting compensation and encourage appropriate risk behavior consistent with Trustmark's risk appetite, business strategy and profit goals. Some of the mitigating features and controls used are the overall compensation mix, weighting of performance metrics, timing of awards in relation to performance measurement period, use of full value equity-based awards with multi-year vesting periods, and establishment of targets with payouts at multiple levels of performance, chargeback provisions on returned or unearned commissions, clawback provisions, capped upside opportunities, and oversight by executive management and the Board. In addition, Trustmark's incentive compensation arrangements are subject to a system of internal controls to ensure that incentive compensation is properly tracked, approved and paid. Trustmark's internal controls include comparisons throughout the year of performance results against performance requirements, approval by appropriate levels of management, the Committee, the Board and/or the Bank Board of incentive compensation payouts, with separate review and approval by division controllers of lines of business that have significant incentive compensation payouts, and coordination among human resources, accounting, finance, and payroll personnel to ensure that incentive compensation payouts that have been approved are appropriately reconciled to those approvals before and after payment is made. As a result, the Committee concluded that Trustmark's compensation policies and practices are not reasonably likely to have a material adverse effect on Trustmark, do not encourage imprudent risk-taking behavior and are consistent with maintaining the organization's safety and soundness.

Deductibility of Compensation.  In making compensation decisions, the Committee considers Section 162(m) of the Internal Revenue Code, which limits the tax deductibility of certain compensation in excess of $1 million paid to Trustmark's NEOs.

Although tax deductibility continues to be a consideration when determining executive compensation levels, the Committee believes that factors other than tax deductibility should take precedence in certain situations. Given the competitive market for outstanding executives, for example, the Committee believes that it is important to retain the flexibility to determine compensation elements consistent with Trustmark's compensation philosophy, even if some executive compensation is not fully deductible under Section 162(m). Accordingly, the Committee does approve elements of compensation for certain executives that are not fully deductible by Trustmark and reserves the right to do so in the future when appropriate. In 2025, a portion of each NEO's compensation was not deductible by Trustmark under Section 162(m).

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Summary Compensation Table for 2025

The following table summarizes the compensation components for each person who served as CEO and CFO during 2025, as well as the next three most highly compensated executive officers during 2025, and indicates their positions as of December 31, 2025. Although considered "officers" of Trustmark Corporation under the Exchange Act, the NEOs' compensation, except for equity awards under Trustmark's stock and incentive compensation plans, is paid by the Bank. The amounts reported in the "Change in Pension Value and Non-QualifiedDeferred Compensation Earnings" column were not paid to the NEOs in any year shown. These amounts represent the annual change in the present value of potential future benefits the NEOs might receive upon retirement, assuming the benefits have vested.

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All Other Compensation for 2025

The detail of all other compensation for 2025 is included in the following table:

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Grants of Plan-Based Awards for 2025

The following table presents information regarding incentive-based cash bonuses and equity awards granted to the NEOs during or for the year ended December 31, 2025, under Trustmark's annual management incentive plan (cash), the Trustmark Stock Plan (restricted stock units) and, in the case of incentive-based awards, reflects the amounts that could be earned or received under such awards: