Proxy Statement (Form DEF 14A)

Unitil Corporation

2025 Proxy Statement

Notice of Annual Meeting of Shareholders

Wednesday, April 30, 2025

11:30 a.m. EDT

Hampton, New Hampshire

March 28, 2025

Dear Fellow Shareholder,

I am pleased to invite you to the Unitil Corporation Annual Meeting of Shareholders to be held on Wednesday, April 30, 2025, at 11:30 a.m. EDT, at our corporate headquarters, 6 Liberty Lane West, Hampton, New Hampshire 03842-1720.

This year, we are asking shareholders to vote on the election of four directors and on the ratification of the selection of independent registered public accountants for fiscal year 2025. Also, this year, shareholders will be presented with an advisory vote on executive compensation.

Your vote is very important. We encourage you to vote to ensure that your voice is represented at the meeting, and to play a part in our future. The enclosed proxy materials provide important information to assist you with your voting decisions and instructions to submit your vote.

I would like to thank you for choosing to invest in Unitil Corporation. Throughout 2024, we honored our commitments to our shareholders, customers, employees, local communities and partners by investing in people, technology, and assets, delivering exceptional customer service, and producing strong financial results. Looking forward, our disciplined approach to operating excellence, financial integrity, and strategy execution will continue to support those commitments.

On behalf of the Board of Directors and management of Unitil Corporation, thank you for your continued support and confidence in 2025.

Sincerely,

Thomas P. Meissner, Jr.

Chairman of the Board and

Chief Executive Officer

NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

The Unitil Corporation (the "Company") 2025 Annual Meeting of Shareholders will be held at the office of the Company, 6 Liberty Lane West, Hampton, New Hampshire 03842-1720, on Wednesday, April 30, 2025, at 11:30 a.m. EDT for the following purposes:

The Board of Directors set February 21, 2025, as the date for determining holders of record of common stock who are entitled to notice of and to vote at the meeting or at any adjournments or postponements of the meeting. The Board of Directors has directed the Company to prepare this notice, the accompanying proxy statement, and the accompanying annual report, and to send them to you.

By Order of the Board of Directors,

Sandra L. Whitney

Corporate Secretary

YOUR VOTE IS IMPORTANT

Your vote is important. To ensure a quorum is present at the Annual Meeting of Shareholders, please be sure your shares are represented at the meeting.

You may vote in one of the following ways:

ATTENDING THE ANNUAL MEETING OF SHAREHOLDERS

All shareholders are invited to attend the Annual Meeting of Shareholders. However, to ensure that the meeting remains orderly and secure, you must follow certain procedures for admittance.

Attending in Person

Shareholders of record will need to provide their name and government-issued picture identification. Beneficial owners will need to provide a copy of an account statement from the bank, broker or nominee holding the shares as proof of ownership as of the Record Date, as well as government-issued picture identification. The safety of our employees and all invited guests and visitors is of primary importance. If you should elect to attend the Annual Meeting in person, you will be expected to follow all directions from Company personnel while inside our corporate office.

TABLE OF CONTENTS

PROXY STATEMENT 

FORWARD LOOKING STATEMENTS

This document contains "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical fact, included herein, including, without limitation, statements regarding our financial position, business strategy and other plans and objectives for our future operations These statements include declarations regarding our beliefs and current expectations. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "should," "expects," "plans," "anticipates," "believes," "estimates," "predicts," "potential" or "continue" or the negative of such terms or other comparable terminology. These forward-looking statements are subject to inherent risks and uncertainties in predicting future results and conditions that could cause the actual results to differ materially from those projected in these forward-looking statements. Risks and uncertainties that could cause our actual results to differ significantly from management's expectations are described in our Annual Report on Form 10-Kfor the year ended December 31, 2024.

  Unitil Corporation

  6 Liberty Lane West

  Hampton, NH 03842-1720

March 28, 2025

PROXY STATEMENT

Unitil Corporation ("Unitil" or the "Company") is providing this proxy statement and the accompanying annual report (which includes the Company's Annual Report on Form 10-Kfor fiscal year 2024) to shareholders in connection with our 2025 Annual Meeting of Shareholders (the "Annual Meeting"). The Board of Directors (the "Board") is soliciting your designation of a proxy to vote your shares at the Annual Meeting. As a shareholder of Unitil, you are invited to the Annual Meeting, as well as entitled and requested to vote (if you are a shareholder of record) or to provide voting instructions (if you beneficially own your shares in street name) on the proposals described in this proxy statement. This proxy statement provides information to assist you in voting your shares or providing voting instructions with respect to your shares.

Unitil has the following subsidiaries, which are referred to throughout this proxy statement: Bangor Natural Gas Company ("Bangor"); Fitchburg Gas and Electric Light Company ("Fitchburg"); Granite State Gas Transmission, Inc. ("Granite"); Northern Utilities, Inc. ("Northern"); Unitil Energy Systems, Inc. ("Unitil Energy"); Unitil Power Corp.; Unitil Realty Corp.; Unitil Resources, Inc.; and Unitil Service Corp.

We may also refer to Unitil as "we" or "our" or "us" throughout this proxy statement.

Date, Time and Place

The Annual Meeting will be held on Wednesday, April 30, 2025, at 11:30 a.m. EDT, at our corporate office, 6 Liberty Lane West, Hampton, New Hampshire 03842-1720.

Anticipated Mailing Date

We anticipate first mailing definitive copies of this proxy statement, the accompanying proxy card, and the accompanying annual report to shareholders on or about March 28, 2025.

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2025 ANNUAL MEETING SUMMARY

This year, we are seeking your vote on the following proposals:

QUORUM & REQUIRED VOTE

A majority of the outstanding shares of common stock entitled to vote at the Annual Meeting must be present in person or represented by proxy to conduct the Annual Meeting. This is referred to as a quorum.

If a quorum is present, the nominees standing for election as a Director will be elected by a plurality of the votes cast by the shareholders. Votes withheld and broker non-voteswill not be counted toward the achievement of a plurality. Additional information concerning the election of directors appears in the sections entitledCorporate Governance - Resignation Policy andProposal 1 - Election of Directors. With respect to all other matters that may come before the Annual Meeting, action on a matter is approved if the votes cast favoring the action exceed the votes cast opposing the action. Therefore, abstentions and broker non-voteswill have no effect on the other matters. Representatives of our transfer agent will count the votes and certify the results.

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VOTING RIGHTS & PROCEDURES

As an owner of Unitil common stock, it is your legal right to vote (or to provide voting instructions) on all matters to be considered at a shareholder meeting. We hope you will exercise your legal right and fully participate as a shareholder in the Annual Meeting. You may cast one vote for each share of common stock that you own on all matters presented at the Annual Meeting.

The Board has selected and approved Robert B. Hevert, Daniel J. Hurstak, and Thomas P. Meissner, Jr. as proxies for the Annual Meeting to vote your shares in the manner that you specify on the proxy card or via the Internet, or if you do not give any specification on your proxy card or submitted proxy with respect to a matter, FOR such matter. Your designation of a proxy will not affect your right to attend the Annual Meeting and vote at the meeting.

Record Holders

If your shares of common stock were registered directly in your name with our transfer agent as of the Record Date, then you are considered a shareholder of record of the shares (a "Record Holder") and we have sent the proxy materials and the accompanying proxy card directly to you.

Beneficial Holders

If your shares of common stock were registered in the name of a bank, broker or other nominee as of the Record Date, then you are considered a beneficial owner ("Beneficial Holder") of the shares that are registered in street name, and your bank, broker or other nominee has sent this proxy statement and voting instructions to you. As a Beneficial Holder, your shares may be voted even if voting instructions are not provided.

Brokerage firms have the authority under New York Stock Exchange ("NYSE") rules to vote shares for which their customers do not provide voting instructions on routine matters. The ratification of the selection of our independent registered public accounting firm, Deloitte & Touche LLP, for fiscal year 2025 is considered a routine matter. When a proposal is not routine and the brokerage firm has not received voting instructions from its customers, the brokerage firm cannot vote the shares on that proposal. Those shares are considered "broker non-votes."Please note that, under NYSE rules, this means that brokers may not vote your shares on Proposals 1 and 3 at the 2025 Annual Meeting if you have not given specific instructions as to how to vote to the broker. Please be sure to give specific voting instructions to your broker so that your vote can be counted.

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A MESSAGE FROM TOM MEISSNER, CHAIRMAN & CHIEF EXECUTIVE OFFICER 

This is a dynamic and exciting time for our industry, and the last 10 years have been truly transformational for both our Company and the industry as a whole. For our Company, 2024 was a year of remarkable achievement. We delivered record-setting financial and operational performance while advancing our strategic priorities and accelerating investments to modernize our energy systems. We believe these accomplishments, combined with our acquisition of Bangor Natural Gas Company ("Bangor") and strong growth in our existing operating companies, positions our Company for long-term sustainable growth in the years ahead.

Operationally, we once again achieved outstanding results in electric reliability and gas emergency response, and maintained our exceptional track record in gas pipeline safety. Customer satisfaction continues to be first-rate as we were again the top ranked utility company in the northeast. These accomplishments reflect strong leadership, commitment to financial integrity and operational excellence, informed management of risk and strategic planning, and our persistent drive to advance new technologies as we work towards the greater goal of a clean energy future. I am very proud of our collective accomplishments in a challenging, yet exciting, year.

As I reflect on 2024, it is inspiring to witness the remarkable ability of our Company and our employees to adapt, innovate, and thrive in an evolving and complex energy landscape. There were both significant opportunities and unique challenges in 2024, from accelerating the clean energy transition to navigating ongoing economic uncertainty and completing the acquisition of Bangor. In spite of it all, we remained focused on the core elements of our business-outstanding operational and financial results, exceptional service to our customers, and strategic innovation for long-term, sustainable growth. Our industry is evolving, and as we continue to focus on these initiatives, we believe our Company will be ideally positioned to succeed today and thrive for years to come.

Over the last decade, our Company has grown and prospered. As we move forward, I am confident that the initiatives and actions we are taking now will shape the successes of tomorrow. It is truly an exciting time to be a part of the energy industry, and I am so pleased you have chosen to share in our journey.

On behalf of the Board of Directors and management, thank you for your continued trust and support. If the last decade is any indicator, the future is indeed bright.

March 28, 2025

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ACTING ON OUR VALUES

Our RISE values represent the principles that guide our actions, but they are only as effective as they are meaningful and measurable. Continued focus on the importance of these values will drive our commitment to deliver 'energy for life' and the achievement of a clean and sustainable energy future for all of our stakeholders.

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The table below shows Executive Officers' biographical information as of the date of this proxy statement, including the Named Executive Officers.

MANAGEMENT INFORMATION TABLE

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The following table sets forth information on the beneficial ownership of our common stock as of the Record Date, by (i) each person known to us to be the beneficial owner of more than five percent of our common stock, (ii) each Director and nominee for Director, (iii) each executive officer named in the Summary Compensation Table in the section entitled Compensation - Compensation of Named Executive Officers(the "Named Executive Officers") and (iv) all Directors and executive officers of Unitil as a group. Except as otherwise indicated, to our knowledge, the beneficial owners listed have sole voting and sole dispositive power with respect to the shares beneficially owned by them. The address of each of Unitil's Directors and executive officers is c/o Unitil Corporation, 6 Liberty Lane West, Hampton, New Hampshire 03842-1720.

BENEFICIAL OWNERSHIP

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NOTES:

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SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

Section 16(a) of the Securities Exchange Act of 1934 ("Exchange Act") requires our executive officers, Directors, and persons who beneficially own more than ten percent of a registered class of our equity securities to file certain reports of ownership and changes in share ownership with the Securities and Exchange Commission ("SEC") and the NYSE. Based upon our review of such forms that were filed in 2024, and written representations from certain reporting persons that such forms were not required to be filed by those persons for the reporting year 2024, we believe that all filing requirements applicable to our officers and Directors during 2024 and through March 2025, were met.

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We are committed to comprehensive and effective corporate governance practices. The Board of Directors (the "Board") and the management team firmly believe that solid corporate governance is key to the transparent and ethical operation of our Company and have set a high standard for this important element in our long-term sustainability and growth goals.

The ethical character, integrity and principles of the Board, senior management, and employees remain the most important safeguards of good corporate governance. These attributes are inherent to engaged leadership, effective management structure, and a committed, carefully-trained workforce.

The Corporate Governance Guidelines and Policies of the Board (the "Governance Guidelines") inform the pursuit of superior Board function, management accountability, effective and transparent disclosure, and financial integrity. Together with the Bylaws and the Code of Ethics Policy, the Governance Guidelines provide a meaningful governance framework upon which we operate.

The Governance Guidelines represent the current view of the Board on governance and should not be viewed as rigid constraints. We will continue to monitor new developments and requirements, as well as emerging issues concerning corporate governance best practices and financial disclosure, and will adopt changes and new policies as appropriate. The Governance Guidelines are reviewed regularly and are subject to modification from time to time by the Board. The Governance Guidelines are available for review on the Corporate Governance page of the Investor Relations section of our website at unitil.com/investors, and are available in print to any shareholder or other interested party free of charge upon request to the Corporate Secretary at 1-800-999-6501or at the address listed in the section entitled Information about the Annual Meeting.

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DIRECTOR INDEPENDENCE

Our Governance Guidelines specify that a majority of the
members of the Board, and all members of the Audit,
Compensation, and Nominating and Governance Committees,
must be independent (as defined in Section 303A.02 of the
NYSE Listed Company Manual-Corporate Governance
Standards). As a listed company on the NYSE, we adhere to
the independence standards set forth by the NYSE. The Board
has formally adopted independence criteria which
corresponds to the NYSE rules for director independence. The
NYSE Listed Company Manual includes additional
independence requirements for Audit Committee and
Compensation Committee members. In addition, Rule 10A-3
of the Exchange Act includes further independence
requirements for Audit Committee members.

Our Governance Guidelines, as well as the NYSE independence standards, require that the Board annually affirm the independence status of non-employeeor "outside" Directors. The Board performs this review and affirmation annually in January, and based on its last comprehensive review on January 29, 2025, the Board determined at that time, with the exception of Mr. Meissner, all of the current Board members are independent. The Board also confirmed that Ms. Kountze, if elected, would be independent.

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During its annual independence review and affirmation, the Board applies the independence standards set forth in our Governance Guidelines and by the NYSE. Under these requirements, the members of the Board who qualify as independent must be free from any material relationship that would interfere with the exercise of independent judgment as a member of the Board. An independent Director is one for whom the Board has affirmatively determined that he or she, individually or through a member of his or her immediate family, does not have or has not had management responsibility with the Company or otherwise been affiliated with Unitil for the past three years and who has no material relationship, either directly or as a partner, shareholder or officer of an organization with such a relationship with Unitil. This definition generally leaves the Board with discretion to determine, on a case-by-casebasis, what constitutes a "material relationship" with us, subject to certain "bright line" independence standards set forth by Section 303.A of the NYSE Listed Company Manual. The Board exercises this discretion in a manner that is consistent with applicable NYSE and SEC regulations and standards. In addition, members of the Board are obligated to notify the full Board of any material changes in their relationships that may affect their independence status as determined by the Board. The obligation encompasses all relationships between Directors and Unitil and its subsidiaries and/or members of senior management.

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LEADERSHIP STRUCTURE

The current leadership structure of the Board consists of a combined chairman and chief executive officer ("CEO") position, which has been held by Mr. Meissner since April 2018.

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RISK OVERSIGHT

As defined in the Board Charter, the Board is responsible for the oversight of management, the development of Company policy and strategy, and the ongoing assessment of our Company's operational effectiveness and financial strength, which includes the oversight of risk. The Board's ultimate goals are to ensure that we continue as a successful and sustainable business, to optimize financial returns in light of the business risks, to increase shareholder value over time, and to protect the interests of all stakeholders.

Our Enterprise Risk Management ("ERM") program has been in place since 2014. The Board has definitive oversight responsibility for the ERM program in accordance with its fiduciary duty, as well as the Board Charter. The ERM program is a foundation for risk management that is relevant, sustainable and scalable. The ERM program is designed to identify existing and potential risks, and to manage risks within our risk appetite in order to sustain operations and achieve business and strategic objectives. Our ERM program includes regular review of new or emerging risks, the assessment of such risks and their potential effects on our Company, the velocity of potential incidents resulting from such risks, and risk mitigation strategies. In building the ERM program, the potential risks relating to our business were originally defined using a comprehensive set of risk disclosures which are described in Part I, Item 1A. Risk Factorsof our Annual Report on Form 10-Kfiled with the SEC. The potential risks relating to our Company that inform our ERM program are reviewed regularly, and most recently described in Part I, Item 1A. Risk Factorsof our Annual Report on Form 10-Kfor the year-ended 2024 filed with the SEC on February 10, 2025, (the "2024 Form 10-K").

In its oversight role, the Board is supported by the Risk and Compliance Committee (the "RCC"), a multi-function management committee that is responsible for the ongoing development and implementation of the ERM program and associated risk management standards. The ERM program is integrated with other assurance and strategy-related functions throughout our Company to ensure appropriate coverage of risks that could impact us. In addition to known risks, the ERM provides for the identification of emerging risks, through participation in industry groups, scenario planning and gap analysis, discussions with designated internal subject matter experts, and in consultation with outside advisers. Management and the RCC then analyze the emerging risks to determine materiality, likelihood, impact, velocity, and appropriate mitigation strategies. A quarterly ERM report, outlining both emerging and ongoing risks as well as management's mitigation efforts, is provided to the Board at each Board meeting.

Our statements of risk appetite and risk tolerance were developed as a joint effort between management and the Board. The importance of the integration of clear statements of risk appetite and risk tolerance to strategy development and implementation were the primary factors considered during this exercise. The Board was guided through the process with management's input and information from the RCC's work with regard to known risks, emerging risks, and opportunities created by well-managed risk. At the conclusion of the exercise, the Board determined our risk appetite and risk tolerance as noted below.

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Like all companies, we face a variety of risks, both internal and external, and many factors work simultaneously to affect our overall business risk. The Board recognizes that our business risk is not static, and that it is not possible to mitigate all risk and uncertainty. The Board works within a climate of respect and candor, fostering a culture of open dialogue between Board members and senior management, which includes comprehensive knowledge of our many elements of risk. Overall, the Board believes that a systematic and proactive approach to properly oversee risk management has been defined and enhanced by the ERM program, which will continue to evolve through ongoing review and assessment of the existing and emerging risks that we face.

CYBERSECURITY OVERSIGHT

As described in the Board Charter, the Board is responsible for oversight of cybersecurity, which is and will continue to be a primary focus. The Board recognizes the protection of our data, customer information and

infrastructure are critical to the ongoing success and prosperity of our Company, and the Board's decision to elevate oversight of cybersecurity to the full Board is appropriate and a matter of good governance.

We maintain a robust Cybersecurity Plan for assessing, identifying, and managing material risks from cybersecurity threats. The intent of the Cybersecurity Plan is to provide a proactive and systemic approach to meet the evolving requirements for cybersecurity and related compliance in the utility industry. The

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Cybersecurity Plan is part of our ERM program, described above, and the Board receives regular cybersecurity updates as part of the ERM report. The Cybersecurity Plan includes annual assessments, the results of which are used to benchmark our cybersecurity posture, to identify risks from cybersecurity threats, to prioritize any such risks that may have potential material effects on our Company, and to establish effective controls to manage, mitigate and remediate such risks.

Cybersecurity awareness and training is a Company-wide initiative, established in 2013, in which all employees participate. The results of our internal, external, and regulatory assessments have routinely demonstrated a high-degree of integrity in our risk, security, and governance practices because of targeted focus, direct investment, and prioritization across our cybersecurity program to protect our assets, customer data, and critical utility services.

To date, there have been no risks from cybersecurity threats (including as a result of previous cybersecurity incidents) that have materially affected or are reasonably likely to materially affect our business strategy, results of operations, or financial condition.

BOARD SUCCESSION PLAN

The Board is engaged in ongoing succession planning (the "Board Succession Plan"), which is led by the Nominating and Governance Committee. The Board Succession Plan addresses upcoming retirements, committee membership and rotation, class balancing, skill set requirements and gaps, and planning for unforeseen events. The Board Succession Plan is also directly linked to both new director recruitment actions and diversity goals.

RETIREMENT POLICY

In general, no Director may be nominated as a candidate for re-electionas part of the slate of Directors that we propose, nor may any person be nominated as a candidate for election, after he or she has reached age 75. Directors are not subject to specific term limits. Due to the complexity of the utility industry, we value the insight that a Director is able to develop over a period of time. The Board believes that tenure provides an enhanced contribution to the Board, including the benefits of valuable experience and familiarity. However, the Board seeks to balance tenure on the Board in the context of overall diversity, as well as to protect against an entrenched Board.

DIRECTORS' STOCK OWNERSHIP AND RETENTION POLICY

The Board believes that its members should make the financial commitment to own a significant number of shares of our common stock to properly align their interests with those of our shareholders. All non-employeeDirectors must own shares of common stock in the equivalent value of three times the current annual cash retainer for Board service. Shares of restricted stock and restricted stock units ("RSUs") are counted towards this total. The ownership requirement is calculated annually on January 1, and as of

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January 1, 2025, the current ownership requirement is $240,000 in value. Mr. Brown, Mr. Collin, Ms. Foster, Mr. Godfrey, Mr. Green, Ms. Vogel and Mr. Whiteley meet the stock ownership requirement. Any new Director who joins the Board has four years from the date of first election to the Board by shareholders to accumulate the required number of shares of common stock, which currently applies to Ms. Alonzo and Ms. Awad, who were first elected in 2023, as well as to Ms. Lewis-Raymond, who was appointed to the Board in October 2024, and Ms. Kountze, if elected at the Annual Meeting. All members of the Board are required to hold all forms of equity received from the Company until retirement or other separation from our Company. For Board members, this includes all forms of equity received as part of the annual retainer for Board service. The Board, in its sole discretion, may approve a waiver to this policy as circumstances may warrant. To date, no such waivers have been proposed or approved.

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EXECUTIVE STOCK RETENTION POLICY

The Board believes that our executive officers should own a significant number of shares of our common stock to properly align their interests with those of the shareholders. All Named Executive Officers are required to hold all forms of equity received as compensation until retirement or other separation from the Company. The Board, in its sole discretion, may approve a waiver to this policy as circumstances may warrant. To date, no such waivers have been proposed or approved.

PROHIBITION ON HEDGING AND/OR PLEDGING COMPANY STOCK POLICY 

All members of our Board and our executive officers are prohibited from engaging in short sales or engaging in any hedging transaction with respect to our common stock, as well as engaging in any transactions that result in pledging, or using as collateral, shares of our common stock in order to secure personal loans or other obligations, including any shares that may be held in a margin account. For more information, see the section entitled Insider Trading Policy, above.

TRANSACTIONS WITH RELATED PERSONS

The Audit Committee is responsible for reviewing and approving, as appropriate, all Related Person Transactions (as defined below), in accordance with its charter (the "Audit Committee Charter") and as prescribed in the NYSE Listed Company Manual, Section 314, Related Person Transactions. As a result, the Committee has adopted procedures for such review and approval and included such procedures in our Governance Guidelines. We had no Related Person Transactions requiring disclosure in 2024, and there are no Related Person Transactions requiring disclosure currently proposed for 2025. "Related Person" and "Related Person Transaction" are defined in Item 404(a) of Regulation S-K("Regulation S-K"),as prescribed under the Securities Act of 1933, as amended (the "Securities Act").

Transactions between us or one or more of our subsidiaries and one or more Related Person may present risks or conflicts of interest or the appearance of conflicts of interest. Our Code of Ethics generally requires all employees, officers and Directors to avoid engagement in activities or relationships that conflict, or would be perceived to conflict, with our interests or adversely affect our reputation. It is understood, however, that certain relationships or transactions may arise that would be deemed acceptable and appropriate upon full disclosure of the transaction, following review and approval to ensure there is a legitimate business reason for the transaction and that the terms of the transaction are no less favorable to us than could be obtained from an unrelated person.

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In connection with the review and approval, if appropriate, of any Related Person Transaction, the Audit Committee will consider whether the transaction will compromise our professional standards included in our Code of Ethics. In the case of any Related Person Transaction involving an outside Director or nominee for Director, the Committee will also consider whether the transaction will compromise the Director's status as an independent Director as prescribed in the NYSE Listed Company Manual, Section 303A, Independent Directors. The procedures followed by the Committee to evaluate transactions with Related Persons are also available on the Corporate Governance page of the Investor Relations section of our website at unitil.com/investors.

COMMUNICATION WITH THE BOARD

Shareholders and other interested parties who desire to communicate with the Board, a committee of the Board, the non-managementor independent Directors as a group, or an individual member of the Board may do so in writing by sending a letter c/o Corporate Secretary, Unitil Corporation, 6 Liberty Lane West, Hampton, New Hampshire 03842-1720 or via email to whitney@unitil.com. The Corporate Secretary will screen all correspondence for security purposes, and will also determine whether the communication relates to business matters that are relevant to us. If the correspondence meets these standards, it will be promptly forwarded to the appropriate Director(s).

NOMINATIONS

The Nominating and Governance Committee is responsible for recommending to the Board the slate of Director nominees for election by our shareholders. The Board reviews and, as appropriate, approves all Director nominees to be presented to our shareholders for election. As provided in Article III of our Bylaws,

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any vacancy occurring in the Board, whether due to the death, resignation or other inability to serve of any Director previously elected may be filled by the affirmative vote of a majority of the remaining Directors.

General Nomination Process

The Nominating and Governance Committee determines the required selection criteria and qualifications for Director nominees based upon the needs of the Company at the time nominees are considered. See also the section entitled Qualifications and Skills of Directors below. Director candidates will be selected based on input from Directors, executive officers, and if the Committee deems appropriate, a third-party search firm. Minimum criteria for Director nominees are set forth below, as well as in the Corporate Governance Guidelines. A candidate must possess the ability to apply good business judgment and must be in a position to properly exercise his or her duties of loyalty and care. Candidates with potential conflicts of interest will be identified and disqualified, as appropriate. The Committee shall ensure there is a robust and diverse initial pool of director candidates. In addition, the Committee will consider criteria including independence, proven leadership capabilities, business experience, areas of expertise, and factors relating to the composition of the Board, including diversity (gender, race/ethnicity, and age), size and structure. The Committee will consider these criteria for nominees identified by the Committee, by other Directors, by shareholders, or through another source. When current Board members are considered for nomination for re-election,the Committee also considers prior Board contributions, performance, meeting preparedness and attendance records.

The Committee makes a preliminary assessment of each proposed nominee based upon his or her resume and biographical information, an indication of his or her willingness to serve and other background information. This information is evaluated against the criteria set forth above as well as our specific needs at the time. Based upon a preliminary assessment of the candidate(s), those who appear best suited to meet our needs may be invited to participate in a series of interviews, which are used for further evaluation. On the basis of information collected during this process, the Committee determines which nominee(s) to recommend to the Board for approval to submit for election at the next annual meeting of shareholders, or to fill vacancies on the Board that occur between shareholder meetings. The Committee uses the same process for evaluating all nominees, regardless of the source of the nomination. The Board may elect, at its discretion, to participate in an additional round(s) of interviews with one or all candidate(s) recommended by the Committee.

The Committee's diligent actions and thorough recruitment process resulted in the addition of six outstanding and highly qualified Board members from 2019 through 2024, all of whom have varied and extensive experience in numerous important areas that have proven to enhance the Board's strong skill set and diversity goals.

Director Candidate Identification and Selection Process in 2024

In anticipation of Mr. Godfrey's retirement from the Board in April 2025, and following the Board's defined succession planning process, the Nominating and Governance Committee began a comprehensive search for a new Board member in early 2024. The Committee consulted the Skills Matrix (described further in the

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Qualifications and Skills of Directorssection below) to determine the primary directives to use to identify qualified candidates. The Committee decided to seek candidates with specialized skills and expertise in some or all of the following areas:

In addition, our diversity policy requires that the initial list of candidates from which Board nominees are chosen includes one or more qualified candidates with diversity of gender and race and/or ethnicity.

The Committee engaged Preng & Associates ("Preng"), an executive search firm dedicated to the energy industry, to produce a comprehensive preliminary list of candidates meeting some or all of the primary directives identified by the Committee. The Committee then selected four of the most qualified candidates from Preng's preliminary list, all of whom met at least two of the skills and experience requirements, and three of whom had diversity of gender, and race and/or ethnicity. Virtual interviews were conducted with each candidate, and based on feedback regarding those interviews, two final candidates were selected. The Committee determined that both candidates were highly qualified by way of their own professional accomplishments. The Committee acknowledged that both candidates would complement the Board's strong culture of respect and collegiality. The Committee and Mr. Meissner conducted formal in-personinterviews with both candidates in late July of 2024. Based on the interviews and further evaluation of each candidate, the Committee decided that both final candidates were extremely well qualified, possessed the desired skills and attributes defined as primary directives, met or exceeded the general selection criteria, and would enhance the positive and productive Board culture. The Committee considered the Board's succession planning needs for both 2025 and 2026, and decided to extend an invitation to join the Board of Directors to both candidates, and to recommend both candidates to stand for election by shareholders at the Annual Meeting.

In October 2024, the Board approved the Committee's recommendation and appointed Jane Lewis-Raymond to the Board. She will serve as an appointed member of the Board until the Annual Meeting, at which time she will stand for election by shareholders at the Annual Meeting. Expanded biographical information for Ms. Lewis-Raymond is included in the section entitled Proposal 1: Election of Directors of this proxy statement.

In January 2025, the Board acted upon the Committee's recommendation and approved Katherine Kountze to be included on the slate of director nominees to stand for election to the Board by shareholders at the Annual Meeting. Expanded biographical information for Ms. Kountze is included in the section entitled Proposal 1: Election of Directors of this proxy statement.

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The Board believes the Committee's well-planned and comprehensive process once again produced an outstanding result with the identification and recommendation of Ms. Lewis-Raymond and Ms. Kountze, two highly-qualified candidates with varied and extensive experience and expertise who will enhance and preserve the Board's existing strong skill set for long-term sustainability and ongoing value creation for our shareholders.

Shareholder Nominations

Shareholders who wish to recommend a nominee for consideration by the Committee may do so by sending the following information to the Committee c/o the Corporate Secretary at the address listed in the section entitled Corporate Governance - Governance Policies of the Board-Communication with the Board: (1) the name of the candidate with brief biographical information and his or her resume; (2) contact information for the candidate and a document evidencing the candidate's willingness to serve as a Director if elected; and (3) a signed statement as to the submitting shareholder's current status as a shareholder and proof of ownership of the number of shares currently held.

Additionally, nominations of persons for election to the Board made by any of our shareholders must comply with all procedures set forth in Article IV - Nomination of Directorsof our Bylaws.

No candidates for Director nominees were submitted to the Committee by any shareholder in connection with the Annual Meeting.

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The Board believes there are general qualifications that all Directors must exhibit, and other qualifications, attributes, skills and experience that should be represented on the Board as a whole, but not necessarily by each Director.

Qualifications Required of All Directors

The Board requires that each Director be a person of high integrity and superior ethical character with a proven record of leadership and accomplishment in his or her chosen field. Each Director must demonstrate innovative and independent thinking, understand complex principles of business, finance, and utility regulation, and demonstrate familiarity with and respect for corporate governance requirements and practices. Directors must also comply unequivocally with the Code of Ethics, and be free of conflicts or potential conflicts of interest, and a sufficient number of Directors must meet the requirements of independence as set forth by the NYSE, as appropriate. Directors must be willing and able to dedicate the proper amount of time and effort to service on the Board as necessary to fulfill his or her responsibilities as a Director. Independent members of the Board may not serve on more than four boards of for-profitcompanies in addition to the Unitil Board. Non-independentmembers of the Board may not serve on more than two boards of for-profitcompanies in addition to the Unitil Board. Service on boards of non-profitorganizations, other industry associations, and community or civic groups is not limited.

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Qualifications, Attributes, Skills and Experience to be Represented on the Board

The Board has identified certain qualifications, skills, experience and backgrounds that it believes are important to be represented on the Board. The Nominating and Governance Committee is charged with the responsibility of tracking the Directors' professional experience and skill sets with a board inventory matrix (the "Skills Matrix"). The Skills Matrix is composed of 13 categories of skills and attributes considered by the Board and the Committee to be advantageous to the regulated utility business, as well as for a company of our size and complexity. The Committee uses this information to assess overall Board composition and to identify existing and potential gaps. This information is also used for recruiting and evaluation purposes when there is a vacancy, or an expected vacancy, on the Board. The Skills Matrix has proven to be a valuable tool in this assessment exercise. The Board strives to represent a meaningful cross-section of business and industry experience, education, and specialized skill sets with individuals who add quality to our corporate governance framework, and who fairly and without compromise execute their fiduciary duty to serve the best interests of our shareholders and all of our stakeholders.

The Skill Sets Summary provides a snapshot of key qualifications and experience that the Board believes should be represented for optimal oversight of our business and the effective exercise of its fiduciary

duty to shareholders. The information provided in the Skill Sets Summary was determined using the skills and demographics declaration where each Board member self-identifies their strongest skill sets. Directors standing for re-electionare also evaluated by the Committee for recommendation to the Board using a set procedure based on the expectations of Board members, which is reviewed annually. The evaluation includes contribution to the Board and committees served upon; unique skills, expertise and attributes; attendance and preparedness; and willingness to continue serving. Overall continuity and chemistry of the Board are also considerations, as well as factors relating to the composition of the Board, such as size and structure, the diversity profile, and the backgrounds, perspectives, experience and skills among its members. The evaluation also includes a discussion with Mr. Meissner to address any concerns, desire to continue serving, or any other matters. Tenure on the Board is considered to be a uniquely valuable qualification in the highly regulated utility industry, although the Board recognizes that a range of tenure is beneficial to avoid complacency and/or Board entrenchment.

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In January 2024, the Nominating and Governance Committee reviewed the Skills Matrix to ensure it continues to reflect the most relevant and essential skill sets and identify any gaps in advance of the recruitment of new Board members in 2024. The Committee elected to make no changes to the Skills Matrix at that time.

BOARD DIVERSITY

The Board's policy is to ensure the composition of the Board reflects gender, racial and ethnic diversity. To advance the Board's policy, the Nominating and Governance Committee ensures that the initial list of candidates from which Board nominees are chosen includes one or more qualified candidates with diversity of gender and race and/or ethnicity. Also, any external search firm retained must also include in its initial list of candidates one or more qualified candidates with diversity of gender and race and/or ethnicity.

Skills and Demographics Declaration

The skills and demographics declaration was added to the Board's general evaluation process to provide a means for each Board member to declare their strongest skill sets and to self-identify demographics, including gender and race/ethnicity. This information is used to inform ongoing accuracy of the Skills Matrix for Board succession planning needs, and to ensure accuracy in our disclosure of these items in our public documents. The skills and demographics declaration was completed by all Board members as part of the 2024 annual evaluation process. Ms. Kountze, who has not yet served as a member of the Board, completed the skills and diversity declaration in conjunction with the pre-onboardingprocess for new Board members, and her responses are included in the skill sets summary in the prior section of this proxy statement.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

The subsection entitled Section 16(a) Beneficial Ownership Reporting Compliancewithin the Share Ownershipsection of this proxy statement is incorporated herein by reference.

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respected, and embrace the genuine benefits that focused and effective human capital management brings to our organization.

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Our Approach

Aligning Sustainability and Risk Management

As climate-related risks evolve, so does the need to align sustainability and the assessment of risk. Our goal is to continuously enhance our understanding of enterprise-wide risk and uncertainty with comprehensive evaluation of current risks, scenario planning, and quantitative analysis. These tools strengthen our ability to successfully integrate sustainability into our strategic decision-making processes. By doing so, we are better able to assess operational, environmental, and social uncertainties and weigh their potential implications for our strategic priorities.

Our Practices and Priorities

Our values state clearly that sustainability initiatives are fundamental to and firmly rooted in our culture. This top-to-bottomemphasis on the very nature of sustainability helps ensure long-term benefits and value creation, and reflects our commitment to our corporate responsibilities to our shareholders, employees, customers, and society at large.

There are four key areas we believe are central to our Company and to the utility industry as the transition to a sustainable future continues. By looking closely at each area, we have identified practices and priorities that demonstrate our commitment to sustainability in support of our stakeholders while simultaneously illustrating our corporate culture in action.

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Our Objective

As we transform our business to meet the needs of future generations, we are fully committed to the environmental, social and governance priorities that matter most to our shareholders and other stakeholders.

While change creates uncertainty for some, those who arrive prepared at these critical moments find great opportunity for growth and long-term benefits for all. With thoughtful planning, informed decision-making, and an inspired, dedicated workforce, we are well-positioned to capitalize on multiple growth opportunities as our industry continues to evolve and embrace the clean energy transition.

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Corporate Sustainability and Responsibility Report

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The Board has the following standing committees: Audit Committee; Compensation Committee; Executive Committee; and Nominating and Governance Committee. The tables below provide a summary of each committee with respect to membership and primary responsibilities.

Audit Committee

The Audit Committee is a separately-designated standing audit committee established in accordance with section 3(a)(58)(A) of the Exchange Act. Each member of the Committee is financially literate, knowledgeable and qualified to review financial statements. The Committee operates under a written charter, which it reviews annually, and adopts amendments, if necessary, to reflect changes governing financial reporting and accounting requirements or its responsibilities. The Audit Committee Report, which appears in the section entitled Audit Matters, more fully describes the activities and responsibilities of the Committee.

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Compensation Committee

NOTES:

Ms. Alonzo joined the Committee on July 31, 2024, and therefore did not attend the meetings held on January 30, April 30, and July 30, 2024. Ms. Lewis-Raymond joined the Committee on October 30, 2024, and therefore did not attend the meetings held on January 30, April 30, July 30, and October 29, 2024.

The Compensation Committee operates under a written charter, which it reviews annually and, as appropriate, amends to reflect changes in its responsibilities. The specific activities and responsibilities of the Committee are described in greater detail in the section entitledCompensation Committee Operations.

Executive Committee

The Executive Committee operates under a written charter, which it reviews annually and, as appropriate, amends to reflect changes in its responsibilities. Committee membership includes the Chairman of the Board, the lead director, and the chairs of the Audit, Compensation, and Nominating and Governance Committees of the Board, as well as any additional Board members appointed at the discretion of the Board.

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Nominating & Governance Committee

NOTES:

Ms. Awad joined the Committee on July 31, 2024, and therefore did not attend the meetings held on January 30, April 30, and July 30, 2024.

The Nominating and Governance Committee operates under a written charter, which it reviews annually and, as appropriate, amends to reflect changes in its responsibilities.

All Committees

The existence and activities of all committees of the Board do not alter the traditional roles and responsibilities of Unitil's management. All committees may delegate authority to individuals or subcommittees when they deem appropriate, subject to applicable laws, rules or regulations. However, in delegating authority, a committee shall not be absolved from the responsibilities designated under the terms of its respective charter. All committees shall undertake any other action or exercise such other powers, authority, duties and responsibilities as necessary or appropriate to the discharge of the duties and responsibilities set forth in their respective charters or our Bylaws, or otherwise required by the listing standards of the NYSE or other applicable laws, rules or regulations, or as shall otherwise be determined by or assigned by the Board.

The charters for each of the standing committees are available in the Corporate Governance section of the Investor Relations section of our website at unitil.com/investors, or in print to any shareholder or other interested party, free of charge, upon request to the Office of the Secretary, Unitil Corporation, 6 Liberty Lane West, Hampton, NH 03842-1720; or to InvestorRelations@unitil.com; or by calling toll free 800-999-6501.

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AUDIT COMMITTEE REPORT 

The following report is submitted by the Audit Committee with respect to our audited financial statements for the fiscal year ended December 31, 2024. In discharging its oversight responsibility regarding the audit process, the Audit Committee has discussed with Deloitte & Touche LLP ("Deloitte"), our Company's independent registered public accounting firm for the fiscal year ended December 31, 2024, the matters required to be discussed by AS 1301, as adopted by the Public Company Accounting Oversight Board. In addition, the Committee has received the written disclosures and the letter from Deloitte required by applicable requirements of the Public Company Accounting Oversight Board regarding Deloitte's communications with the Committee concerning independence and has discussed with Deloitte the firm's independence with respect to our Company.

During 2024, the Audit Committee members received quarterly financial information for review and comment prior to the filing of each of our Forms 10-Qwith the SEC. In fulfilling its responsibilities relating to the financial statements, the Committee also reviewed and discussed our significant accounting policies and the audited financial statements for the fiscal year ended December 31, 2024, with management and Deloitte. Based on the review and discussions with management and Deloitte, the Committee recommended to the Board that the audited financial statements be included in the 2024 Form 10-Kfor filing with the SEC.

Audit Committee Members

Anne L. Alonzo, Mark H. Collin, Edward F. Godfrey, Michael B. Green, and Justine Vogel (chair)

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PRINCIPAL ACCOUNTANT FEES & SERVICES

The following table presents fees for professional services rendered by Deloitte, Unitil's independent registered public accounting firm, for the fiscal years ended December 31, 2024, and December 31, 2023.

Audit Fees

In 2024 and 2023, this category includes fees incurred for professional services rendered by Deloitte for reviewing the quarterly financial statements included in our Quarterly Reports on Form 10-Q,auditing our annual financial statements included in our Annual Report on Form 10-K,and auditing our internal control over financial reporting. In addition, in 2024, this category also includes fees incurred of approximately $60,000 for audit services rendered by Deloitte related to the Company's customer information system upgrade in the first quarter of 2024.

Audit-Related Fees

In 2024 and 2023, this category includes fees of $30,000 and $22,500, respectively, incurred for professional services rendered by Deloitte in connection with our filing of registration statements with the SEC.

Tax Fees

In 2024 and 2023, Deloitte did not perform any tax services.

All Other Fees

In 2024 and 2023, this category includes fees of $3,790 for cost-based non-auditservices consisting of subscriptions to DART (the "Deloitte Accounting Research Tool").

AUDIT COMMITTEE PRE-APPROVALPOLICY

The Audit Committee's formal policy is that all services to be provided by the independent registered public accounting firm engaged to audit our consolidated financial statements, including audit services and permitted audit-relatedand non-auditservices, must be pre-approvedby the Committee. The Committee pre-approvedall audit, audit-related,tax and all other services provided by Deloitte during fiscal 2024 and 2023.

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COMPENSATION COMMITTEE OPERATIONS

The Compensation Committee is appointed annually by the Board and is responsible for, among other things, oversight of the executive compensation program. The Committee has overall authority to establish goals and objectives and to interpret the terms of our compensation policies, including base salary, incentive compensation, equity compensation, and all benefits programs. The Committee discharges its oversight responsibilities by carrying out the specific functions and exercising the authority provided in its charter (the "Compensation Committee Charter"). See the section entitled Compensation - Compensation of Named Executive Officers - Compensation of Directors for information on the Nominating and Governance Committee's work regarding Directors' compensation.

The Committee has the authority to delegate some of its responsibilities to individuals or subcommittees of the Committee's choice, subject to applicable laws, rules or regulations. However, such delegation does not absolve the Committee from the responsibilities that it bears under the terms of the Compensation Committee Charter.

The Committee has the authority to invite executive officers, members of management or other guests to attend meetings, to perform research, or to provide relevant information or recommendations. In 2024, at the Committee's request, Mr. Meissner, Mr. Hevert, Mr. Hurstak, and the vice president of people, shared services and organizational effectiveness, John Closson, served the Committee in a consultative capacity, providing data and analytical support, as well as management perspective and recommendations relative to employee compensation and benefits, including executive compensation.

The Committee also has the authority to retain or obtain the advice of outside counsel, compensation consultants or other advisors to advise the Committee as it deems necessary. The Committee is directly responsible for the appointment, retention terms (including compensation), and oversight of the work of any adviser it retains. Prior to retaining or obtaining advice from an adviser, the Committee will consider factors relevant to the adviser's independence from management to the extent required by the NYSE listing standards.

The Committee has periodically engaged a compensation consultant, Willis Towers Watson ("Willis Towers"), to provide compensation study data, including data from selected peer companies and compensation marketplace survey analysis, as well as to provide various recommendations based on study findings and industry trends for the Committee's consideration. Willis Towers is engaged by and reports directly to the Compensation Committee. Willis Towers receives compensation only for services related to executive compensation, employee benefits and general compensation matters, and neither it nor any affiliated company provides any other services to us or our subsidiaries.

The Compensation Committee engaged Willis Towers in 2024 to conduct a comprehensive review and assessment of senior management compensation, including the CEO, president, and CFO compensation, non-unionemployee compensation, employee benefits, and directors' compensation, (the "2024 Compensation Analysis"). The Committee requested Willis Towers to provide an assessment of current levels of competitive compensation and broad-based benefit programs to assist the Committee with its decisions concerning 2025 compensation. See the section entitled Compensation - Compensation Discussion and Analysis for additional information on the 2024 Compensation Analysis and the Committee's work in 2024 regarding compensation-related matters for the 2025

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compensation year. See also the section entitled Compensation - Compensation Discussion and Analysis for additional information on the comprehensive compensation analysis prepared by Willis Towers in 2019 and the Committee's work regarding compensation-related matters for compensation years 2020-2024.

In 2024, we incurred total expenses of $205,298 for services rendered by Willis Towers. The services were approved by the Compensation Committee as part of the Willis Towers 2024 engagement.

In addition, we requested and received information from Willis Towers to assist the Committee in determining whether its work raised any conflict of interest. Based on the responses provided by Willis Towers in its completed Conflict of Interest Questionnaire, there were no conflicts of interest in 2024.

COMPENSATION COMMITTEE INTERLOCKS & INSIDER PARTICIPATION

The current members of the Compensation Committee are not current or former officers or employees of Unitil. No member of the Committee has any relationship requiring disclosure under Item 404 of Regulation S-K,Transactions with Related Persons. In addition, none of our executive officers serve on the board of directors or compensation committee of another company where an executive officer of the other company also serves on the Board or Compensation Committee.

RISK & BROAD-BASED COMPENSATION PROGRAMS

We believe the risks that may arise from our compensation policies and practices, which include the annual short-term incentive award performance metrics, long-term incentive award performance metrics, variable and non-variablepay mix, and limited non-performancepayouts, are not likely to have a material adverse effect on us because of multiple factors that work together, as summarized below.

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COMPENSATION DISCUSSION & ANALYSIS

2024 PERFORMANCE REVIEW

Operations and Safety

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Customer Service

Employee Satisfaction and Culture

Infrastructure Investments

Regulation

Sustainability / Carbon Reduction Commitment

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In addition to the operational successes noted above, we also continued to advance our long-term strategic planning initiatives, including customer engagement, clean transportation, renewable energy, operating systems' integrity, grid modernization, and employee engagement. We continued to accelerate dividend growth for our investors continuing our unbroken record of annual dividend payments in 2024. On January 31, 2024, the Board of Directors approved an increase in the annualized dividend to $1.70 per share, maintaining our dividend payout ratio near the low end of our long-term target range of 55% - 65%. On January 29, 2025, the Board of Directors voted to increase the 2025 annualized dividend to $1.80 per share.

EXECUTIVE COMPENSATION POLICIES

EXECUTIVE COMPENSATION RECOVERY POLICY

The purpose of the Executive Compensation Recovery Policy (the "Policy") is to provide for the recovery of certain executive compensation in the event of an accounting restatement resulting from material noncompliance with financial reporting requirements under the securities laws. In the event we are required to prepare an accounting restatement of our financial statements due to material non-compliancewith any financial reporting requirement, we shall be entitled to recover any excess performance-based compensation received by any current or former Covered Executive⁵ during the three-year period immediately preceding the date on which we are required to prepare an accounting restatement. "Performance-based compensation⁶" is defined as all annual incentives and long-term incentives (whether in cash, in equity, or otherwise) granted, earned, vested or unvested with performance features based wholly or in part on our Company's or a specified group's attainment of a financial reporting measure. "Financial reporting measures" is defined as measures that are determined and presented in accordance with the accounting principles used in preparing our financial statements, and any measure(s) that are derived wholly or in part from these measures. We shall recover any erroneously awarded performance-based compensation in accordance with the Policy, with the exception that if the conditions of Rule 10D-1of the Exchange Act and the listing standards of the NYSE are met, the Compensation Committee

determines that recovery would be impractical. All actions taken under this Policy will comply with Section 10D of the Exchange Act and the listing standards of the NYSE.

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EXECUTIVE STOCK OWNERSHIP POLICY

All Named Executive Officers of our Company are required to own shares of our common stock in the equivalent value of a multiple of base salary. Any newly appointed Named Executive Officer will have four years from the date of appointment to obtain the required shares of stock. Additional information concerning the current share ownership of our Directors and officers can be found in the section entitledShare Ownership -Beneficial Ownership.

EXECUTIVE STOCK RETENTION POLICY

The Board believes that our executive officers should own a significant number of shares of our common stock to properly align their interests with those of our shareholders. All Named Executive Officers are required to hold all forms of equity received as compensation until retirement or other separation from the Company. The Board, in its sole discretion, may approve a waiver to this policy as circumstances may warrant. To date, no such waivers have been proposed or approved.

PROHIBITION ON HEDGING AND/OR PLEDGING COMPANY STOCK POLICY

All members of the Board and the executive officers are prohibited from engaging in short sales or engaging in any hedging transaction with respect to Unitil common stock, as well as engaging in any transactions that result in pledging, or using as collateral, shares of Unitil common stock in order to secure personal loans or other obligations, including any shares that may be held in a margin account.

TIMING AND PRICING OF STOCK AWARDS

While we do not have a formal policy regarding the timing of equity awards, our practices regarding the grant of equity awards are designed to comply with applicable securities laws, and to reflect the integrity of our executive compensation program. The Board, together with the Compensation Committee, are responsible for determining the timing and terms of equity awards to eligible persons, including Named Executive Officers, other employees, and Directors. We do not grant equity awards in anticipation of the release of material non-public information, and we do not time the release of material non-public information based upon grant dates of equity. Equity awards are granted in connection with our yearly compensation cycle at pre-scheduled meetings. Currently, we do not issue stock options or SARS, and there are no stock options or SARS outstanding.

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Compensation Philosophy and Administration

The Compensation Committee is responsible for oversight of our executive compensation program. The Committee, the Board and management recognize the value and importance of sound principles for the development and administration of competitive compensation and benefit programs. We believe our executive compensation program:

The Compensation Committee uses a set of guiding principles in the design and implementation of the Company's executive compensation program, which are outlined above. The primary goal of the guiding principles is to ensure consistency and fairness in all aspects of the Committee's oversight of compensation policy. Additional information concerning the processes and operational procedures followed by the Committee can be found in the section entitledCompensation-Compensation Committee Operations.

Compensation Policy & Process

The principal objective of our executive compensation program is to attract, motivate, retain and reward highly qualified employees committed to the achievement of solid financial performance, outstanding service to customers, and excellence in the management of our assets. It is our belief that a strong sense of teamwork and shared responsibility are vital to achieving strong performance. Our incentive compensation reflects and supports this philosophy with an appropriate balance of financial and operational goals that apply to the entire management team. See the section entitled Compensation - Compensation Discussion and Analysis-Elements of Compensationfor a discussion of the specific goals set, and results achieved, for 2024. We also believe that retention of talented and dedicated key executives will help ensure continued focus on the achievement of long-term growth in shareholder value and overall sustainability, which in turn will provide significant benefits to all of our stakeholders, including shareholders, customers and employees.

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Compensation Policy - What We Do & What We Do Not Do

The Compensation Committee continuously strives to make improvements to our executive compensation policies. Below is a summary of what we do and what we do not do with respect to executive compensation, the totality of which the Committee and the Board believe aligns with the long-term interests of our shareholders as well as with today's commonly accepted best practices in the market.

Compensation Decisions for 2020 - 2024

In order to prudently manage outside consulting expenses, the Compensation Committee decided to forego consulting work related to overall executive pay in the years 2020, 2021, 2022, and 2023. Instead, the Committee determined the information contained in the comprehensive 2019 Compensation Analysis remained relevant and therefore was used as an across-the-boardassessment benchmark. The Committee also used existing compensation programs and policies previously found to be reasonable and competitive to evaluate overall executive compensation for 2021, 2022, 2023 and 2024. The Committee recommended and the Board approved executive compensation paid in January of each respective year as noted. We continue to include the details of the 2019 Compensation Analysis, which is described below, as it is the base benchmark for executive compensation disclosed in this proxy statement.

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2019 Compensation Analysis - Summary

The 2019 Compensation Analysis scope included an overall analysis of our compensation as it relates to and supports our business strategy, alignment with the compensation philosophy, peer group identification, detailed information on executive, non-unionstaff and Directors' compensation, as well as a review of the research methodology and process, key findings with regard to base salary and incentive compensation, program assessment, and several recommendations for the Committee's consideration.

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General Methodology

Towers Watson used both compensation data from published compensation surveys focused on comparably sized organizations in the utility sector and general industry sector (for "cross industry" positions), and compensation data from proxy filings of our approved peer group of 13 publicly traded utility companies with annual revenues between $275 million and $1.6 billion (the "2019 Peer Group")⁷, which was approved by the Compensation Committee in April 2019 for the purposes of this Analysis.

Compensation Data from Published Compensation Surveys

Compensation data from published compensation surveys focused on comparably sized organizations in the utility sector and general industry sector (for "cross industry" positions)⁸. Published survey data were size-adjustedbased on revenue, employee regression and/or scope parameters. Because the surveys are confidential, the specific data selected by Willis Towers did not indicate survey participants by company name.

Compensation Data from Proxy Filings

Compensation data was also extracted from the 2019 Peer Group proxy filings. The Compensation Committee used this data to analyze only the CEO's and CFO's compensation, with the objective of ensuring that CEO and CFO total compensation was reasonable, competitive and consistent with pay practices at peer companies.

Published compensation surveys generally provide a broader sample of data upon which to base compensation decisions, which is essential when analyzing a large number of positions as was the case with the 2019 Compensation Analysis. Data from peer company proxy filings generally validate published survey information with definitive executive compensation data from specific companies.

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Willis Towers completed the 2024 Compensation Analysis in October 2024. Deliverables included a review of the research methodology and process, key findings with regard to base salary and incentive compensation, program assessment, and several recommendations for the Committee's consideration. Results of the Directors' competitive assessment were also provided to the Nominating and Governance Committee. Please see the section entitledCompensation - Compensation of Directors for additional information on the Nominating and Governance Committee's actions concerning Directors' compensation.

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The Committee used the information provided in the 2024 Compensation Analysis:

The Committee did not use any information provided in the 2024 Compensation Analysis for decisions or consideration relating to 2024 compensation.

Salary Administration

Our Salary Administration Policy has three objectives:

The Salary Administration Policy includes three important components:

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Base Salary

We set base salary ranges for every job grade and position based upon salary survey data provided by Willis Towers and in accordance with the Salary Administration Policy described above. In relation to each Named Executive Officer, base salary is set within the salary range based upon individual experience, skills, and education, as well as performance relative to individual annual goals. This process is used for both executive and non-executivepositions.

Short-Term Incentive Compensation - Cash Incentive

We set annual target cash incentive awards equal to the median of the broad-based published compensation survey group for the executive officers' target cash incentive awards at other comparable companies based on data provided by Willis Towers. The Committee also used information from the proxy statements of our peer group, at the 25^th percentile target, as a secondary source to set the CEO's and CFO's annual target cash incentive award. We have developed a "balanced score card" approach to setting goals for the annual incentive awards, which includes certain goals from the Strategic Plan that represent success in financial results, electric reliability, gas safety, customer service and distribution cost per customer. The Compensation Committee approves the quantitative goals, also referred to as performance metrics, for these awards annually. See the section entitled Compensation - Compensation Discussion and Analysis - Elements of Compensationfor a discussion of the balanced score card.

Long-Term Incentive Compensation - Equity Compensation

We grant shares of restricted stock to selected management participants in the Third Amended Stock Plan generally on an annual basis. The size of the annual restricted stock award (the "target award") is based upon the midpoint of the participant's salary grade, multiplied by the participant's salary grade multiplier (i.e., the equity compensation opportunity percentage), divided by the 30-dayaverage stock price of our common stock¹⁰, less the percentage of anticipated Federal and Medicare taxes to equal the number of

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shares to be granted. The salary grade multiplier is based on research data provided by Willis Towers in their competitive assessment (the "Assessment") of long-term incentive compensation ("LTI") program design conducted in 2021. Willis Towers incorporated information from the proxy statements of our peer group into the Assessment as a benchmark to set the salary grade multiplier.

All Named Executive Officers are required to hold all forms of equity, vested or unvested, received as compensation until retirement or other separation from Unitil. The Board, in its sole discretion, may approve a waiver to this policy as circumstances may warrant. However, to date, no such waiver has been requested or granted.

Performance-Related Incentive Compensation

In addition to individual performance, overall Company performance is a critical component in the determination of how each individual executive is paid relative to the market median of the broad-based published compensation survey group, as described above. See also the section entitled Compensation - Compensation of Named Executive Officers - Proportional Compensation for additional information on performance-related compensation.

CEO Pay Ratio

Summary

As required by the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the "Dodd-Frank Act"), the SEC adopted a rule requiring annual disclosure of the ratio of the median employee's annual total compensation to the total annual compensation of the principal executive officer. Our principal executive officer is Mr. Meissner (the "CEO").

We believe the compensation program and salary administration policy should be consistent and internally equitable to motivate all employees to perform in ways that enhance shareholder value. We also believe that our compensation philosophy and processes yield an equitable result for all employees, which is reflected in the resulting ratio.

Methodology

To reasonably identify the median employee, we prepared a list of all active employees (excluding the CEO) as of December 31, 2024. The list included part-time employees. As of December 31, 2024, we employed 544 people of which 372 were non-unionemployees and 172 were union employees covered by a collective bargaining agreement.

Next, we extracted the taxable wages number reported in Box 1 of the 2024 Form W-2from our payroll records for each employee, excluding the CEO. We did not annualize wages and salaries for those employees who were not employed for the full year of 2024. The median employee was then identified based on taxable wages as reported on Form W-2.Once identified, we calculated the median employee's total annual compensation in the same manner as "Total Compensation" shown for the CEO in the Summary Compensation Table in the section entitled Compensation - Compensation of Named Executive Officers.

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Results

The table below shows the information used for the calculation of the ratio of the estimated annual total compensation of the median employee identified using the methodology described above to the annual total compensation of Mr. Meissner as calculated for the Summary Compensation Table.

NOTES:

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Shareholder Advisory Vote on Executive Compensation

As required by the Dodd-Frank Act, we must provide the opportunity for shareholders to vote, on an advisory basis, on the compensation of executives (commonly known as a "say-on-pay"proposal). We present the say-on-payproposal to our shareholders annually.

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ELEMENTS OF COMPENSATION

Base Salary

Every employee is paid a base salary. The purpose of base salary is to reward employees for the expertise and value they bring to their jobs. Base salary is determined according to our salary policy, which assigns each position a grade and a corresponding salary range. We set salary ranges for every position based upon comparative salary data provided by Willis Towers. The midpoint of the salary range is set at the median level of the broad-based published compensation survey group when compared to similar positions at comparable companies. The minimum parameter in the salary range is determined by multiplying the midpoint by 80%, and the maximum parameter is determined by multiplying the midpoint by 120%. The salary range is then used to manage each employee's salary, which is based on merit, within the range. For each employee (including Named Executive Officers), base salary is set within the salary range based upon individual performance relative to individual annual goals. The elements of individual performance differ depending on the individual position, but generally include: quality of work; successful completion of established goals; ability to initiate creative solutions; adaptability to change; and impact on our overall performance. The salaries of all employees (including the Named Executive Officers) are reviewed annually, as well as at the time of a promotion or change in responsibilities.

individual goals established at the beginning of the year. Executive officers' merit increases also include evaluation of overall Company performance for the year. Merit increases are generally effective as of January 1 of each year. Merit increases also are one of the methods used to reach one of our competitive compensation guiding principles, which is to ensure that employees are paid at or near the market median of the broad-based published compensation survey group. Merit increases may also be adjusted by the Compensation Committee to reflect the market value of a job when compared to similar positions at other companies within our peer group, as recommended by Willis Towers.

The process followed to determine base salary increases for the Named Executive Officers begins with an annual summary and evaluation of Unitil's overall performance provided to the Board by the CEO, which generally occurs in mid-January.The Compensation Committee and the Executive Committee meet jointly in executive session to discuss the evaluation of our overall performance, as well as to discuss the CEO's performance in relation to our performance for the year, considering both the quantitative and qualitative aspects of the performance of both the CEO and our Company as a whole. The Compensation Committee uses the feedback gained in the joint meeting along with the market competitive salary information previously described to determine an appropriate base salary increase for the CEO based on both merit and market conditions. The CEO provides a recommendation to the Compensation Committee for base salary increases for the other Named Executive Officers. The Compensation Committee then reviews and

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recommends the base salaries of all of the Named Executive Officers to the full Board for discussion and approval. The Committee's recommendations are based on the performance evaluations and market information for each of the Named Executive Officers. Each Named Executive Officer received the base salary increase percentage from 2023 to 2024 as noted in the table above.

Incentive Compensation

Management Incentive Plan

The Unitil Corporation Management Incentive Plan (the "Management Incentive Plan") provides annual cash incentive payments based upon the attainment of specified goals selected from the Strategic Plan. The Compensation Committee selects participants in the plan and establishes their individual target awards. All executives (including the Named Executive Officers) are participants in the Management Incentive Plan. The purpose of the Management Incentive Plan, which is consistent with our principal compensation objective, is to provide executives with significant incentives related to performance, thereby providing motivation to maximize efforts on behalf of all of our stakeholders. The Management Incentive Plan is further intended to provide executives with competitive target levels of total compensation when considered with base salaries.

For the annual incentive awards, annual quantitative performance goals are established by the Compensation Committee. These goals, which relate to key performance metrics selected from the Strategic Plan, are the same for all employees (including executive officers) to ensure that employees are focused on common bottom-line business, customer service, and operational results. These goals are discussed below in the subsection entitled Incentive Compensation Performance Metrics and Goals. Under the Management Incentive Plan, executive officers receive a cash award if the quantitative goals that are set by the Committee are met. Each executive officer's Management Incentive Plan target award is established as a percentage of base salary based on the market median of the broad-based published compensation survey group for his or her position when compared to other comparable companies, calculated using data provided by Willis Towers. The Committee also used information from the proxy statements of our peer group, at the 25^th percentile target, as a secondary source to set the CEO's and CFO's Management Incentive Plan target award. The table above shows the Management Incentive Plan target awards for 2024 performance as a percentage of base salary for the Named Executive Officers.

Actual awards may be less than or greater than the target awards depending upon final results achieved. In

addition, the Committee has the authority to increase or decrease the annual cash incentive award under

the Management Incentive Plan when the final results calculation does not properly balance the interests of employees and shareholders. The Committee also has the sole discretion to pay no award when one would otherwise be paid. The Committee has in the past exercised its discretion to both increase and decrease award payments and chose not to do so in 2021, 2022 or 2023. However, for the award for 2024 results, the

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Committee exercised its authority to adjust the cash incentive award to account for the transaction costs associated with our acquisition of Bangor Natural Gas Company. For additional information on the Committee's decision to adjust the award, please see the section entitledIncentive Compensation Performance Metrics and Goals, below.

Third Amended and Restated 2003 Stock Plan

The Unitil Corporation Third Amended and Restated 2003 Stock Plan (as amended, the "Third Amended Stock Plan") was initially approved by shareholders at the 2003 annual meeting of shareholders, amended and restated on March 24, 2011, amended and restated, effective April 19, 2012, and again amended and restated, effective May 1, 2024. Participants in the Third Amended Stock Plan currently include Directors, executive officers and other employees selected by the Compensation Committee. Common stock, restricted stock and restricted stock units ("RSUs") may be issued to participants in the Third Amended Stock Plan. The objectives of the Third Amended Stock Plan are directly tied to the principal compensation objective. The maximum number of shares that may be issued under the Third Amended Stock Plan is 1,027,500, and an aggregate of 333,568 shares remain in reserve for issuance under the Third Amended Stock Plan as of the Record Date.

The Committee believes that equity-based compensation ensures that executive officers have a continuing stake in our long-term success. As described elsewhere in this proxy statement, executive officers are

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taxes. The Total Number of restricted shares provides a
market competitive award while minimizing both dilution and volatility. The table above summarizes the 2024 multiplier for Mr. Meissner, Mr. Hevert, Mr. Hurstak, Mr. Eisfeller, and Mr. LeBlanc.

Time Restricted Shares

Time Restricted Shares generally vest over a period of four years at a rate of 25% each year. Prior to the end of the vesting period, Time Restricted Shares are subject to forfeiture if the Participant's employment terminates other than due to death, disability or retirement. During the vesting period, dividends on Time Restricted Shares are paid to the Participants.

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Performance Restricted Shares

Performance Restricted Shares generally vest after a performance period of three years based on the attainment of certain performance thresholds of certain defined performance metrics, each as set by the Compensation Committee at the beginning of the performance period. On January 30, 2024, the Compensation Committee selected two performance metrics for the three-year performance period starting January 1, 2024, through December 31, 2026:

Performance Restricted Shares are generally granted at target at the beginning of the performance period.

Summary of Time Restricted Shares and Performance Restricted Shares

The following table summarizes certain terms of the Time Restricted Shares and the Performance Restricted Shares.

NOTES:

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Prior to the end of the performance period, the Performance Restricted Shares are subject to forfeiture

if the Participant's employment terminates other than due to death, disability or retirement. In the event of death, disability or retirement, vesting will be pro-ratedbased on the number of months of service completed during the performance period.

Stock Ownership & Holding Requirement for Executive Officers

The Board believes that executive officers of the Company should own a significant number of shares of our common stock to properly align their interests with those of our shareholders. All Named Executive Officers are required to own shares of Unitil common stock in the equivalent value of a multiple of base salary. All shares of Unitil common stock that are owned directly or beneficially, shares of restricted stock that are awarded, whether vested or unvested, as well as any shares of stock held in the Unitil Stock Fund of the Tax Deferred Savings and Investment Plan will be counted towards the required total. Any newly appointed Named Executive Officer will have four years from the date of appointment to obtain the required shares of stock. As of the date of this proxy statement, all current Named Executive Officers have met the stock ownership requirement, with the exception of Mr. Hurstak. Mr. Hurstak was appointed Senior Vice President, Chief Financial Officer and Treasurer of the Company in May 2023, and he will have until May 2027 to meet the ownership requirement.

All Named Executive Officers are also required to hold all forms of equity received as compensation until retirement or other separation from the Company. The Board, in its sole discretion, may approve a waiver to this policy as circumstances may warrant. To date, no such waivers have been proposed or approved. Additional information concerning the share ownership of Named Executive Officers can be found in the section of this proxy statement entitled Share Ownership - Beneficial Ownership.

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Management Incentive Plan Performance Metrics and Goals

The Management Incentive Plan includes performance metrics and goals that are integral to determine any officer's compensation awarded. The current performance metrics and goals are also linked to the Strategic Plan.

Selecting the Performance Metrics and Setting the Goals

Performance metrics and goals are recommended by management annually as part of the strategic planning process. In the Strategic Plan, performance metrics and goals are aligned with the strategies defined for the coming year. The Strategic Plan includes suggested targets for each performance metric, which is reviewed and approved by the Board each year. The Compensation Committee then selects the key performance metrics to be applied to the Management Incentive Plan.

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The table below shows the short-term performance metrics selected and goals set by the Committee for the 2024 annual cash incentive awards under the Management Incentive Plan, as well as the performance results calculated for 2024.

2024 PERFORMANCE METRICS, GOALS & RESULTS

The Total Weighted Performance Factor of 112% for 2024 indicates the payout percentage relative to Target used to calculate the actual cash awards for Management Incentive Plan participants using the applicable formula described in the section entitled Incentive Compensation Formulas.

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2024 Key Performance Metrics and Goals: Defined

Earnings Per Share ("EPS")

The goals for the EPS metric are set as a target based on the approved current year EPS budget with a plus/minus 5% range to maximum and threshold, respectively, from the target value. The Compensation Committee set the 2024 EPS target equivalent to our budgeted 2024 EPS of $2.96, and agreed that a 5% range from the approved budget to the threshold is a practical goal, and a 5% range from the approved budget to the maximum is a reasonable stretch goal considering, among other things, the continued economic uncertainty in early 2024. The Committee also agreed that the plus/minus 5% range provided good symmetry in the goals for this metric.

Gas Safety

Gas safety is measured as the percentage of the response time to natural gas odor calls answered within a pre-setresponse time window. In 2024, the response time target is based on a best in class 30-minuteresponse standard based on a three-year historical trend. Similar to electric reliability, described below, the shorter the response time standard, the more rigorous the target. In defining the threshold, the Committee considered the minimum acceptable percentage to be not less than 84% and the maximum percentage to be at least 88% of the natural gas odor calls responded to in person be within 30 minutes. For 2024, we responded to 90.83% of our natural gas odor calls within the 30-minute pre-setresponse time window.

Electric Reliability

Electric reliability is benchmarked using an industry standard index, SAIDI (System Average Interruption Duration Index). SAIDI represents the total length of time the average customer is without electric service during the year, measured in minutes. For added perspective on this metric, a lower number of minutes (without electric service) equates to a more stringent target. The target for reliability performance is set using the rolling five-year average of the median of peer group reliability based on the national Institute of Electrical and Electronics Engineers ("IEEE") benchmarking survey.¹² In 2024, we achieved exceptional electric service reliability with a SAIDI of 85.20 minutes, marking two consecutive years of top-quartilereliability performance.

Customer Satisfaction

Customer satisfaction is measured using direct customer survey feedback to the question "How satisfied are you with the service, excluding price, you are receiving from Unitil?"as compared to the current national benchmark for residential customer satisfaction as compiled by an independent human behavior and analytics firm. The survey is administered twice each year from a system-generated random selection of customers from our database. The national benchmark in 2024 was 84%, which was set as the target, with maximum and threshold at plus or minus 5%, respectively. In 2024, despite comparatively high energy costs in the New England region, we exceeded the target with 90% in overall customer satisfaction. From a benchmarking perspective, compared to our defined utility peer groups (eastern U.S. and northeast U.S. regions), we ranked first among eight northeast U.S. utilities, and first among 23 eastern U.S. utilities.

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Cost Per Customer

Distribution cost per customer is measured against our same-year approved operations and maintenance ("O&M") cost per customer budget. Results are weighted 50% electric and 50% gas. The minimum and maximum range stretch factors are determined from the previous 10 years' O&M budget variance standard deviation. Target is determined using a stretch factor of zero. For added perspective on this metric, a lower cost per customer equates to a more stringent target. For 2024, our O&M cost per customer for electric division customers was $344.12, and $508.89 for gas division customers.

Cash Incentive Compensation Formula

The Role of the Compensation Committee

The Compensation Committee Charter provides the Committee with the authority to approve annual cash incentive and long-term compensation plan restricted stock awards in light of the established corporate goals and strategic objectives; to determine whether annual and/or long-term incentive compensation plan awards have been earned; and to apply a qualitative adjustment to increase or decrease the annual cash incentive award under the Management Incentive Plan. The Committee has in the past exercised discretion to both increase and decrease award payments when such calculation did not properly balance the interests of employees and shareholders and chose not to do so in 2021, 2022 or 2023. However, for the award for 2024 results, the Committee exercised its authority to adjust the cash incentive award. For additional information on the Committee's decision to adjust the cash incentive award, please see the section entitledIncentive Compensation Performance Metrics and Goals, above.

The Committee meets annually in the first fiscal quarter to review the performance metrics and results for the previous year, and to approve the annual cash incentive awards and the annual grant of restricted stock awards under the Third Amended Stock Plan. The Committee approved the annual cash incentive awards

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under the Management Incentive Plan for 2024 performance on January 28, 2025. The Committee approved the grant of restricted stock awards under the Third Amended Stock Plan on January 30, 2024. For additional information see the section entitled Elements of Compensation - Long-Term Equity Incentive Compensation Programof this proxy statement.

Other Benefits

Unitil Corporation Retirement Plan

The Unitil Corporation Retirement Plan (the "Retirement Plan") is a traditional Defined Benefit Pension Plan covering certain employees of Unitil and our subsidiary companies that provides retirement income benefits based upon years of service, age at retirement and final five-year average salary. The Retirement Plan is closed to new participants, effective January 1, 2010. Employees hired after January 1, 2010 participate in an enhanced 401(k) plan instead of the Retirement Plan. In addition, at the time of closure of the Retirement Plan, existing employee participants were offered a one-timeopportunity to elect to remain an active participant in the Retirement Plan, or to accept a frozen Retirement Plan benefit and move to the enhanced 401(k) Plan.

Supplemental Executive Retirement Plan

The purpose of the Supplemental Executive Retirement Plan (the "SERP") is to provide enhanced retirement benefits to certain key executives selected by the Board in order to encourage continued service by these executives until retirement. Currently, Mr. Meissner is the only active employee participant in the SERP. The SERP was closed to any new entrants in 2018. See also the Pension Benefits Table in the section entitled Compensation - Compensation of Named Executive Officersfor the present value of the accumulated benefit for each Named Executive Officer.

Deferred Compensation Plan

The Unitil Corporation Deferred Compensation Plan (the "DC Plan") is a non-qualifieddeferred compensation plan that provides a vehicle for participants to accumulate tax-deferredsavings to supplement retirement income. The DC Plan is open to senior management or other highly compensated employees with a salary grade of 23 or higher who do not participate in the SERP. The DC Plan may also be

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used as a tool for recruitment and retention purposes for newly hired senior executives. The DC Plan design mirrors our Tax Deferred Savings and Investment Plan formula, but provides for contributions on compensation above the IRS limit, which allows participants to defer up to 85% of base salary, and up to 85% of any cash incentive, for retirement. The Board may also elect to make discretionary contributions on behalf of any participant in an amount determined by the Board. Mr. Hevert, Mr. Hurstak, Mr. Eisfeller and Mr. LeBlanc currently participate in the DC Plan.

Change of Control Agreements

We provide certain executives with protection from job loss due to a change of control in the Company in the form of Change of Control Agreements ("CoC Agreements"). This protection is primarily provided so that the executives will make decisions and take actions that are in the best interest of shareholders and not unduly influenced by the fear of job loss.

All existing CoC Agreements are two-year"double trigger" agreements, meaning that two events must occur in order for payments to be made: (i) a change of control must occur; and (ii) an adverse employment action must occur, meaning that we must terminate the executive's employment other than for cause or disability or the executive must terminate his or her employment for good reason. Double trigger agreements were chosen to protect the shareholders from executives choosing to resign as result of a change of control where there is no adverse employment action. No existing CoC Agreements contain any excise tax or other gross up provision of any kind. We believe that all CoC Agreements comply with the provisions of IRS Code Section 409A. See also the section entitled Compensation-Compensation of Named Executive Officers - Potential Payments Upon Termination or Change of Controlfor a full description of "change of control" as defined in the CoC Agreements.

Employment Agreement - Thomas P. Meissner, Jr.

We entered into an employment agreement (the "Employment Agreement") with Mr. Meissner on April 25, 2024, for a term of three years, which is a renewal of his prior employment agreement that expired on April 24, 2024. For a detailed description of the Employment Agreement, see the sections entitled Compensation-Compensation of Named Executive Officers- Employment Agreement of the Chief Executive Officer and Compensation-Compensation of Named Executive Officers- Potential Payments Upon Termination or Change of Control.

Executive Perquisites

We limit the use of perquisites as a method of compensation. In 2024, Mr. Meissner received a monthly automobile allowance, and Mr. LeBlanc was provided with a Company-owned automobile for business and personal use. Please see the All Other Compensation column of the Summary Compensation Table in the section entitled Compensation-Compensation of Named Executive Officers. The perquisite provided to Mr. Meissner is pursuant to his employment agreement, and with the exception of Mr. LeBlanc as described above, no perquisites are provided to any other Named Executive Officer.

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INTERNAL REVENUE CODE SECTION 162(M)

In general, under Section 162(m) of the Internal Revenue Code of 1986, as amended (the "Code"), we cannot deduct, for federal income tax purposes, compensation in excess of $1,000,000 paid to the CEO, CFO and certain executive officers. However, for prior to the 2018 tax year, this deduction limitation did not apply to compensation that constituted "qualified performance-based compensation" within the meaning of Section 162(m) of the Code and applicable regulations, as then in effect. In 2018, the "qualified performance-based compensation" exception under Section 162(m) of the Code was eliminated, other than with respect to compensation payable pursuant to a written binding contract that was in effect on November 2, 2017, and is not materially modified after that date. For the 2024 tax year, the deduction limitation applied to all Named Executive Officers. The Committee reserves its right to authorize executive compensation that may or may not be subject to the deduction limitations of Section 162(m) of the Code when it believes that such compensation is appropriate and in the best interests of our Company and our shareholders.

OTHER EMPLOYEE BENEFITS

For employees hired after December 31, 2009, this subsidy ends when the retiree reaches age 65. Post-retirement benefits for employees represented by unions are administered in accordance with the applicable collective bargaining agreement.

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COMPENSATION COMMITTEE REPORT

This report is submitted by the Compensation Committee of Unitil with respect to the review and approval of the Compensation Discussion and Analysis, which appears above.

In discharging its oversight responsibility, the Compensation Committee has reviewed and discussed the Compensation Discussion and Analysis required by Item 402(b) of Regulation S-Kwith management, and has recommended to the Board that the Compensation Discussion and Analysis be included in this proxy statement for the Annual Meeting.

Compensation Committee Members

Anne L. Alonzo, Neveen F. Awad, Winfield S. Brown (chair), Jane Lewis-Raymond, and David A. Whiteley

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COMPENSATION OF NAMED EXECUTIVE OFFICERS

Summary Compensation Table

The table below shows the information specified in paragraph (c)(2) of Item 402 of Regulation S-Kconcerning the compensation of the CEO, the CFO, and our three other most highly compensated officers for each of fiscal years 2022, 2023, and 2024.