UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material Pursuant to §240.14a-12

WESCO INTERNATIONAL, INC.

(Name of Registrant as Specified In Its Charter)

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

Payment of Filing Fee (Check all boxes that apply):

☒ No fee required

☐ Fee paid previously with preliminary materials

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

Notice of 2026 Annual Meeting of Stockholders

Dear Fellow Stockholders:

I am pleased to invite you to attend our 2026 Annual Meeting of Stockholders. It will be held via live audio webcast on May 28, 2026. Details regarding the items of business to be conducted at the Annual Meeting are described in the accompanying Proxy Statement:

We are sending a Notice Regarding the Availability of Proxy Materials to you on or about April 17, 2026. Stockholders of record at the close of business on March 30, 2026 will be entitled to vote at our Annual Meeting or any adjournments or postponements of the meeting. You have a choice of voting online during the open poll section of the meeting, over the internet, by telephone, or by requesting a paper copy of the proxy materials and a proxy card and then executing and returning the proxy card. In order to assure a quorum, please vote over the internet or by telephone, or request a paper copy of a proxy card and then complete, sign, date and return the proxy card in the postage-paid envelope provided, whether or not you plan to attend the meeting.

Thank you for your ongoing support of Wesco.

By order of the Board of Directors,

John J. Engel

Chairman, President and Chief Executive Officer

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders to be Held on May 28, 2026

The 2026 Proxy Statement and 2025 Annual Report of WESCO International, Inc. (“Wesco” or the “Company”) are available to review at: www.proxydocs.com/wcc. A copy of our Annual Report on Form 10-K is available upon request, at no cost. Any request should be directed to our Corporate Secretary at the Company’s headquarters office located at 225 West Station Square Drive, Suite 700, Pittsburgh, Pennsylvania 15219-1122.

Questions and Answers

What is a proxy or proxy statement?

The Board is soliciting your proxy to vote at the Annual Meeting. A proxy is your legal designation of another person to vote the stock you own – that person is sometimes called “your proxy”. A proxy statement is a document that the Securities and Exchange Commission (the “SEC”) regulations require us to provide to you when we ask you to sign a proxy to designate someone to vote on your behalf.

Why did I receive a Notice Regarding the Availability of Proxy Materials? What is included in the proxy materials?

We are pleased to continue to utilize the SEC “Notice and Access” rule, which allows companies to distribute proxy materials to stockholders over the internet. A Notice Regarding the Availability of Proxy Materials (a “Notice”) contains instructions on how to access the proxy materials online, describes the matters to be considered at our Annual Meeting, and provides instructions on how to vote your shares. By using the Notice and Access model, we are reducing costs and minimizing the environmental impact of our Annual Meeting. We encourage you to sign up for direct email notice of the availability of future proxy materials by submitting your email address when you vote your proxy via the internet.

The proxy materials for the Annual Meeting include the Notice, this Proxy Statement, and our Annual Report on Form 10-K. If you receive a paper copy of these materials, the proxy materials also include a proxy card or voting instruction form. Proxy materials are first being made available to stockholders on April 17, 2026.

What does it mean if I receive more than one Notice?

If your shares are registered differently or held in multiple accounts (for example, some shares may be registered directly in your name and some may be held in the Company’s 401(k) Retirement Savings Plan), you may receive more than one Notice from the Company or, if your shares are beneficially owned (also known as held in “street name”), from your broker, bank or other nominee. Please carefully follow the instructions on each Notice you receive and vote all proxies to ensure that all your shares are voted.

What is the record date?

The Board established March 30, 2026 as the record date. If you owned shares of the Company’s Common Stock at the close of business on March 30, 2026, you may vote at the Annual Meeting. On that date, there were 48,744,192 outstanding shares of our Common Stock. Each share of Common Stock is entitled to one vote on each matter presented for consideration and action at the Annual Meeting.

How do I attend the Annual Meeting?

Our Annual Meeting will be exclusively conducted via live audio webcast. We are pleased to leverage technology to expand stockholder access and allow for stockholders to participate from any location around the world and save Wesco and its stockholders time and money. We have designed the virtual meeting with the aim of providing all stockholders the same rights and opportunities to participate as they would have at an in-person meeting. In addition to online attendance, our meeting format provides stockholders with the opportunity to hear all portions of the official meeting, submit written questions, and vote online during the open poll section of the meeting.

You may attend the meeting webcast by visiting http://www.virtualshareholdermeeting.com/WCC2026. You will need the 16-digit control number received with your Notice. If a bank, brokerage firm, or other nominee holds your shares, you should contact that organization for additional information. Rules of conduct for our Annual Meeting will be available once you access the meeting webcast.

The meeting is scheduled to begin at 2:00 PM EDT on May 28, 2026, and online check-in is scheduled to begin at 1:45 PM EDT We encourage you to access the meeting platform prior to the meeting start time. The virtual meeting platform is supported across most

internet browsers and devices (such as desktops, laptops, tablets, and cell phones) running the most up-to-date version of applicable software and plug-ins. Participants should ensure that they have a sufficient internet connection wherever they intend to participate in the meeting. If you encounter any technical difficulties when accessing or using the virtual meeting website, please call the technical support number that will be posted on the meeting website login page.

How can I ask questions during the Annual Meeting?

The virtual format allows stockholders to communicate with us in advance of, and during, the Annual Meeting so they can ask questions of our Board of Directors or management. To submit a question, you must login to the meeting platform using your control number, locate the “Ask a Question” section of the page, select a topic from the “Question Topic” menu, type your question into the “Submit a Question” field, and click “Submit.” During the Annual Meeting, we will answer questions submitted that are relevant to the business of the Annual Meeting as time permits and in accordance with our meeting rules and procedures. In the interest of addressing as many stockholder questions as possible in the time allotted, stockholders will generally be limited to one question per proposal and questions that are substantially similar may be grouped and answered once. Questions that are not relevant to the official business of the Annual Meeting or that include derogatory, offensive, or uncivil language or that are otherwise inappropriate or not suitable for the conduct of the Annual Meeting will not be addressed during the meeting. Responses to any questions appropriately submitted and relevant to the official business of the Annual Meeting that were not answered during the meeting due to time constraints will be posted to our Investor Relations website (https://investors.wesco.com) as soon as practicable after the Annual Meeting.

What are the proposals to be voted on at the Annual Meeting? How many votes are needed to approve each proposal? How do abstentions and broker non-votes affect the voting results?

Action may be taken at the Annual Meeting with respect to any other business that properly comes before the meeting, and the proxy holders have the right to and will vote in accordance with their judgment on any additional business.

How do I cast my vote?

There are four different ways you may cast your vote. You may vote by:

The deadline for voting by internet, telephone, or mail is receipt by 11:59 PM EDT on May 27, 2026. If you have any questions or need assistance with voting, please contact our proxy solicitor, Innisfree M&A Incorporated (“Innisfree”) at (888) 750-5834 (for shareholders) or (212) 750-5833 (for banks and brokers).

How do I revoke or change my vote?

If you have returned a proxy via the internet, telephone or mail, you may revoke it at any time before it is voted at the Annual Meeting by:

What is the difference between holding shares as a registered stockholder and a beneficial holder?

If your shares are registered directly in your name with our transfer agent, Computershare, then you are considered a registered stockholder with respect to those shares. If you hold your shares through an intermediary, such as a bank, broker, or other nominee (sometimes referred to as shares held in “street name”), then you are considered the beneficial holder of those shares.

What if I don’t indicate my voting choices?

If you are a registered stockholder and return your signed proxy card but do not mark the boxes showing how you wish to vote on any particular matter, your shares will be voted in the manner recommended by our Board on each matter presented in this Proxy Statement.

If you are a beneficial holder, then your broker, bank or other nominee will ask you how you want to vote your shares. If you give the broker, bank or nominee instructions, your shares will be voted as you direct. If you do not give instructions, your broker, bank or nominee may vote your shares only on proposals that are considered routine matters. The only routine matter being proposed for stockholder vote at the Annual Meeting is the proposal to ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2026. So, without voting instructions from the beneficial owner of the shares, brokers, bank or other nominee holders will not have discretionary authority to vote the shares at the Annual Meeting on any of the other proposals. We encourage you to provide instructions to your bank, broker or nominee by carefully following the instructions provided. This will ensure that your shares are voted at the Annual Meeting as you direct.

Who will count the votes?

Representatives of Broadridge Financial Solutions, Inc. (“Broadridge”) will tabulate the votes, and there will be a duly appointed inspector of election who will certify his or her examination of the list of stockholders, the number of shares held and outstanding as of the record date, and the necessary quorum for transaction of the business for this meeting. These persons will count the votes at the Annual Meeting.

How many votes must be present to hold the Annual Meeting? What is a quorum?

A quorum of stockholders is required to conduct business at the Annual Meeting. A quorum is met if the holders of a majority of the outstanding shares of the Company’s Common Stock entitled to vote at the Annual Meeting are present either in person or by proxy at the Annual Meeting. Abstentions, broker non-votes and votes withheld from Director nominees count as shares present for purposes of determining a quorum.

How will Wesco solicit votes and who pays for the proxy solicitation?

Wesco pays the cost of preparing our proxy materials and soliciting your vote. We have engaged Innisfree to assist with the solicitation of proxies for an estimated fee of $20,000 plus expenses. Wesco will reimburse brokerage firms and other persons representing beneficial owners of shares for reasonable expenses incurred by them in forwarding proxy-soliciting materials to such beneficial owners. Proxies may be solicited on our behalf by our Directors, officers, employees and agents, without additional remuneration, by telephone, electronic or facsimile transmission or in person.

May I elect to receive a paper copy of proxy materials in the future?

Stockholders can elect to receive future Wesco Proxy Statements and Annual Reports via paper copies in the mail.

If you are a registered stockholder, you can choose to receive future Annual Reports and Proxy Statements via paper copy at no charge by writing to WESCO International, Inc., 225 West Station Square Drive, Suite 700, Pittsburgh, Pennsylvania, 15219-1122, Attention: Corporate Secretary. If you are a beneficial holder, follow the information provided by your nominee for instructions on how to elect to receive paper copies of future Annual Reports and Proxy Statements.

If you enroll to receive paper copies of Wesco’s future Annual Reports and Proxy Statements, your enrollment will remain in effect for all future stockholders’ meetings unless you cancel the enrollment.

What is householding?

Stockholders who share the same last name and address will receive one package containing a separate Notice for each individual stockholder at that address. Stockholders who have elected to receive paper copies and who share the same last name and address will receive only one set of our Annual Report on Form 10-K and Proxy Statement, unless such stockholders have notified us that they wish to continue receiving multiple copies. This method of delivery, known as “householding,” will help ensure that stockholder households do not receive multiple copies of the same document and lowers the costs and the environmental impact of our Annual Meeting.

If you are a registered stockholder, you can opt out of the householding practice and receive prompt delivery of a separate copy of the materials by calling Broadridge at 1-866-540-7095. If you would like to opt out of this practice and you are a beneficial holder, please contact your bank or broker.

If you receive multiple copies of proxy materials at your household and would prefer to receive a single copy of these materials, please contact Broadridge at the above telephone number. If you are a beneficial holder, please contact your bank or broker.

Proposal 1 — Election of Directors

The following Director Nominees have been nominated for election to our Board for a term expiring at the 2027 Annual Meeting of Stockholders: John J. Engel, Glynis A. Bryan, Michael L. Carter, Anne M. Cooney, Matthew J. Espe, Sundaram Nagarajan, James L. Singleton, Easwaran Sundaram, Laura K. Thompson and David C. Wajsgras.

Our Board unanimously recommends a vote “FOR”

each of the Director Nominees.

Board of Directors

The Board of Directors is composed of twelve directors as of the filing date of this Proxy Statement. Two directors, Bobby J. Griffin and Steven A. Raymund, will retire from the Board at the end of their current term and are not standing for re-election at the 2026 Annual Meeting. The Director Nominees are to be elected at the Annual Meeting for a one-year term expiring in 2027, subject to earlier retirement, resignation or removal.

The following is the complete list of individuals who comprise our Board of Directors and Board Committees as of March 30, 2026.

The following information is provided regarding our Directors as of March 30, 2026:

The following information is provided regarding our Directors as of May 28, 2026, following the retirements of Messrs. Griffin and Raymund at the end of their current term, assuming all Director nominees are elected at the 2026 Annual Meeting:

Our Board proactively seeks Director candidates to provide representation of relevant and varied backgrounds, perspectives, skills, and experiences in our business and in the boardroom. During the past eight years, the Board has added six new Directors as part of its on-going refreshment process, including two new Directors in January 2026.

The matrix below describes the self-identified gender and race or ethnicity attributes of our Directors:

Director Skills, Experience, and Background

The Board regularly reviews the relevant skills, experiences, and backgrounds that it believes are desirable to be represented on the Board and, in conjunction with the Board’s refreshment process described herein, has evaluated these skills and qualifications to align with the Company’s strategic vision, business and operations. The following is a description of some of these skills, experiences and backgrounds, along with the percentage of our Directors that bring such skills and qualifications to the Board.

Board composition is assessed by the Nominating and Governance Committee and the Board to achieve the appropriate mix of skills and experiences so that the Board, taken as a whole, is well-situated to fulfill the needs of the Company and its stockholders. Also, it is considered particularly beneficial that 100% of Board members have strategic leadership, executive management leadership, and operational expertise, as well as international experience and public company board service.

Nominee Directors to Serve for a One-Year Term Expiring in 2027

Corporate Governance

Corporate Governance Guidelines, Committee Charters and Other Governance Policies

We have adopted Corporate Governance Guidelines in conformity with the New York Stock Exchange ("NYSE") listed company standards to provide a framework to assist members of our Board in fully understanding and effectively implementing their responsibilities while assuring our on-going commitment to high standards of corporate conduct and compliance. Our Board has adopted written charters for each of its committees: the Audit Committee, the Compensation Committee, the Nominating and Governance Committee, and the Executive Committee.

We have adopted a Wesco Code of Business Conduct and a Global Antibribery and Anticorruption Policy which apply to our Board of Directors and all of our employees and cover all areas of professional conduct, including customer relations, conflicts of interest, insider trading, financial disclosure, and compliance with applicable laws and regulations. We have adopted a Political Contribution Policy, which, together with our Code of Business Conduct, outlines our policies regarding corporate political contributions.

We also have adopted a Code of Principles for Senior Financial Executives, referred to as the Senior Financial Executive Code, which applies to our Chief Executive Officer, Chief Financial Officer and Corporate Controller. We disclose amendments to, or waivers from, the Senior Financial Executive Code on the corporate governance section of our website within four business days of any amendment or waiver.

You may access our Corporate Governance Guidelines, Committee Charters, Code of Business Conduct, Global Antibribery and Anticorruption Policy, Senior Financial Executive Code, Independence Policy, Political Contribution Policy, and related documents on our website at https://www.wesco.com/us/en/our-company/corporate-responsibility/governance-guidelines-and-policies.

Director Independence

Our Board has adopted independence standards that meet or exceed the independence standards of the NYSE, including the enhanced independence requirements for audit and compensation committee members. In addition, as part of our independence standards, our Board has adopted standards to assist it in evaluating the independence of each of its Directors. The standards are intended to assist our Board in determining whether or not certain direct or indirect relationships between its Directors and our Company or its subsidiaries are “material relationships” for purposes of the NYSE independence standards. The standards establish thresholds at which any relationship is deemed to be material.

Annually, the independence of each Director is reviewed, applying applicable independence standards. The review considers relationships and transactions between each Director and his or her immediate family and affiliates and our management and our independent registered public accounting firm. Based on this review, our Board has affirmatively determined that the following Directors are independent: Messrs. Carter, Espe, Griffin, Nagarajan, Raymund, Singleton, Sundaram, and Wajsgras and Messes. Bryan, Cooney and Thompson.

Director Qualifications

Our Nominating and Governance Committee reviews with the Board at least annually the qualifications of new and existing Board members, considering the level of independence of individual members, together with such other factors, including overall skills and experience. Each Director’s particular and specific experience, qualifications, attributes or skills which support his or her position as a Director on our Board include those that are identified in the Proposal 1 – Election of the Board of Directors section of this Proxy Statement.

The Nominating and Governance Committee considers various factors in determining whether to recommend a candidate for nomination as a Director, including an individual’s aptitude for independent analysis, level of integrity, personal and professional ethics, soundness of business judgment, relevant experience, skills, and ability and willingness to commit sufficient time to Board activities. As part of this annual review, Directors disclose their service on other boards, which the Nominating and Governance Committee takes into consideration when evaluating a Director’s ability to devote sufficient time to the Company’s Board. The Nominating and Governance Committee consults with the Board to determine the most appropriate combination of characteristics, skills and experiences for the Board as a whole with the objective of having a Board whose members have a variety of backgrounds and experiences and sufficient domain knowledge of the Company’s end markets and distribution industry. The Nominating and Governance Committee considers candidates' professional experience and evaluates each individual in the context of the individual’s potential contribution to the Board as a whole to best promote the success of the Company’s business, represent stockholder interests through the exercise of sound judgment, and allow the Board to benefit from the group’s range of backgrounds, experiences and skills.

The Nominating and Governance Committee also reviews the characteristics of incumbent Board members and prospective Board members to ensure that the Board, as a whole, possesses the experience, expertise and competencies that are relevant or desirable. The Nominating and Governance Committee uses a skills matrix to assess the overall composition of the Board, including such characteristics as CEO experience, strategy and operational expertise, financial expertise, capital markets expertise, human capital management expertise, sustainability and environmental expertise, corporate governance experience, risk management experience, supply chain and industry experience, mergers and acquisitions experience, international experience, and technology and cybersecurity experience, among others. These processes are designed to ensure a high-functioning and well-composed Board of independent and capable Directors with relevant experience.

The Nominating and Governance Committee may also target prospective candidates for Board membership based on their attributes compared to current Board members to achieve a strong overall Board composition. The Nominating and Governance Committee applies the same criteria to all candidates that it considers, including any candidates submitted by stockholders.

Board Refreshment and Tenure

The Board is committed to ongoing Board refreshment. The Board considers a balanced Board in terms of overall average Director tenure, comprising newer Directors as well as those who have longer experience with the Company, to benefit the Company and its stockholders by providing fresh perspectives, experience and stability. As part of its Board refreshment process, the Board has recruited a new Director in six of the past eight years. Currently, 46% of our independent Directors have a tenure of five years or less, and the average tenure of our independent Directors as of March 30, 2026 is 8.62 years with a median tenure of 7.62 years. Two our current Directors, Bobby Griffin and Steven Raymund, will retire from the Board at the end of their current term on May 28, 2026. Immediately following the 2026 Annual Meeting, and assuming all Director nominees are elected, 56% of our independent Directors will have a tenure of five years or less, and the average tenure will be 7.14 years and median tenure will be 6.66 years. In order to develop a balanced Board, we have a robust Director recruitment process that includes utilizing the assistance of a nationally recognized recruiting firm to identify and recruit potential candidates for our Board of Directors based on attributes outlined on a skills matrix that was developed by the Nominating and Governance Committee. For each recruiting engagement, the Nominating and Governance Committee, working with the independent recruiting firm and including input from the Board, develops specifications for each director position, which are used to identify and recruit director candidates.

Board, Committee and Director Evaluations

The Board has established a robust self-evaluation process for the Board, its Committees and individual Directors. Each year, our Board and Committees conduct evaluations to assess their effectiveness and adherence to the Corporate Governance Guidelines and Committee charters, and to identify opportunities to improve Board and Committee performance. As part of that process, we also conduct individual Director evaluations, including peer assessments. As described below, the Board engages an independent corporate governance professional to conduct interviews with each Director as part of this process.

Under the leadership of our Lead Director, Mr. Singleton, our annual evaluation process focused on three components: (1) the Board, (2) Board Committees and (3) individual Directors. An independent third party who is experienced in corporate governance matters interviews each Director to obtain his or her assessment of the effectiveness of the Board and its Committees, including identifying any opportunities the Board can focus on to enhance effectiveness. In addition, each Director had the opportunity to provide feedback on his or her peers. Our Lead Director provides overall Board and Committee evaluation feedback and leads a discussion with the entire Board, and also provides feedback to each Director in an individual session.

Director Continuing Education

As part of our efforts designed to ensure a continuing high-performance Board, Directors participate in continuing education on current topics and developments. We bring outside experts into the Board room to review current topics and developments in their areas of expertise, and Directors regularly attend outside education sessions on relevant topics. Education topics include corporate governance, compensation, SEC developments, financial matters, economic developments, artificial intelligence, emerging technology and trends, risk management, cybersecurity, and others.

Compensation Committee Interlocks

None of our executive officers serves as an executive officer of, or as a member of, the compensation committee of any public company that has an executive officer, director or other designee serving as a member of our Board. No member of our Compensation Committee has been an executive officer of the Company.

Executive Sessions and Lead Director Responsibility

During 2025, the non-management members of our Board met in executive session at each regularly scheduled Board of Directors’ meeting. Our Directors generally hold executive sessions at both the beginning and end of each Board meeting. As Lead Director, Mr.

Singleton presided over these executive sessions. In addition, Mr. Singleton has broad authority to call and conduct meetings of the independent Directors. The duties and responsibilities of our Lead Director are described in more detail in the section below.

Board Leadership Structure

Since 2011, Mr. Engel has served as Chairman of the Board. The Board believes that Mr. Engel’s combined role of Chairman and Chief Executive Officer is in the best interests of the Company and its stockholders at this time, and that Mr. Engel is the Director best situated to serve as Chairman because of his detailed and in-depth knowledge of the issues, opportunities and challenges facing the Company, his familiarity with the Company’s business and industry, and his ability to identify strategic priorities essential to the future success of the Company. The Board believes that this structure is best for the Company because it provides for clear leadership responsibility and accountability, while providing for effective corporate governance and oversight by an independent Board of strong and seasoned Directors with an independent Lead Director. Mr. Singleton serves as the Board’s independent Lead Director and presides over executive sessions of the Board. The non-management members of our Board meet in executive session at each regularly scheduled Board meeting. The Audit, Compensation, and Nominating and Governance Committees are all chaired by and composed solely of independent Directors in accordance with independence standards of the NYSE, and thus oversight of key matters is entrusted to the independent Directors. Each of these Committees also meets in executive session without members of management present. The responsibilities of the Lead Director include the following:

The Lead Director assures that appropriate independence is brought to bear on important Board and governance matters. In addition, there is strong leadership vested in and exercised by the independent Committee chairs, and each Director may request inclusion of specific items on the agendas for Board and Committee meetings.

Considering all of the above, the Board believes that a combined Chairman and Chief Executive Officer, together with the Lead Director, is an appropriate Board leadership structure and is in the best interests of the Company and its stockholders at this time.

Communications with Directors

Our Board has established a process by which stockholders and other interested parties may communicate with the Board, our Board Committees, and/or individual Directors by confidential e-mail. Such communications should be sent in writing to the e-mail address noted in the corporate governance section of our website at https://www.wesco.com/us/en/our-company/leadership.html#contact.

Our Chief Compliance Officer will review all of these communications on a timely basis, and our General Counsel will forward appropriate communications (i.e., other than solicitations, invitations, advertisements, or similar communications) to the relevant Board members on a timely basis.

Stockholders who wish to communicate with our Board in writing via regular mail should send correspondence to: WESCO International, Inc., 225 West Station Square Drive, Suite 700, Pittsburgh, Pennsylvania, 15219-1122, Attention: Corporate Secretary.

Our Board members routinely attend our Annual Meeting of Stockholders. This provides you with additional opportunities to communicate with our Board. All of our Board members were present at our Annual Meeting of Stockholders.

Director Nominating Procedures

Our Nominating and Governance Committee recommends potential candidates for nomination as Director based on a number of criteria, including the needs of our Board. Any stockholder who would like the Nominating and Governance Committee to consider a candidate for Board membership should send a letter of recommendation that includes:

To allow for timely consideration, recommendations must be received not less than 90 days prior to the first anniversary of the date of our most recent Annual Meeting. In addition, the Company may request additional information regarding any proposed candidates. A stockholder who wishes to nominate a person for election as a Director must provide written notice to the Corporate Secretary of the Company at the address below in accordance with the procedures specified in Section 2.15 of our By-Laws. In general, to be timely, the written notice must be received by our Corporate Secretary not less than 90 days prior to the first anniversary of the date of our most recent Annual Meeting. The notice must provide certain information required by the By-Laws, including (a) biographical and share ownership information of the stockholder (and certain affiliates), (b) descriptions of any material interests of the stockholder (and certain affiliates) in the nomination and any arrangements between the stockholder (and certain affiliates) and another person or entity with respect to the nomination, (c) certain biographical, employment and specific qualifications information of each nominee, and (d) a brief description of any arrangement or understanding between each individual proposed as a nominee and any other person pursuant to which the individual was selected as a nominee. Any notice of director nomination submitted must comply with the additional requirements of, and include the additional information required by, Rule 14a-19(b) under the Securities Exchange Act of 1934, as amended.

Notices of Director recommendations or Director nominations, including the information described above, should be sent to: WESCO International, Inc., 225 West Station Square Drive, Suite 700, Pittsburgh, Pennsylvania, 15219-1122, Attention: Corporate Secretary.

Director Resignation Policy

The Board has adopted a resignation policy under which any Director who does not receive a majority of votes cast for his or her re-election is expected to offer his or her resignation for the Board’s consideration.

Stockholder Engagement

We seek to engage with current and prospective investors throughout the year in order to review our financial performance, business model and strategic initiatives, so that management and the Board can better understand stockholder perspectives. We also utilize these discussions to assess emerging issues that may help shape our practices and enhance our corporate disclosures, including in the areas of environmental, social and governance issues, executive compensation and capital deployment strategies. We strive for a collaborative approach with our stockholders and value the variety of perspectives that we hear in our discussions with them.

Board’s Role in Oversight of Risk Management

Management is responsible for risk management, and the Board’s role is to oversee management’s efforts in this area. As part of their regular meetings and deliberations, the Board and its Committees review and discuss matters of significance regarding operational, financial and other risks that are relevant to the Company’s business. Strategic risks and operating risks are monitored by the Board through discussions regarding the Company’s strategic and operating plans and regular reviews of the Company’s operating performance. Certain topics, including succession planning and mergers and acquisitions, are of such importance that they are reviewed by the full Board and not delegated to a specific committee. In addition, management assesses the Company’s enterprise risk and reviews with the entire Board significant risks and associated mitigating factors on an annual basis.

Our Board has tasked designated standing committees with oversight of certain categories of risk management. The risk oversight focus areas of the committees are:

The Audit Committee, which is composed 100% of independent members, discusses and reviews guidelines and policies with respect to risk assessment and risk management and discusses with management the Company’s major financial risk exposures and the steps management takes to monitor and control such exposures. The Audit Committee is also responsible for oversight of cybersecurity risk. The Compensation Committee, which is composed 100% of independent members, reviews the potential for risk related to the Company’s compensation arrangements, including compensation arrangements and policies for executives, and determines whether any such arrangements are likely to encourage excessive or inappropriate risk taking. The Nominating and Governance Committee, which is composed 100% of independent members, is responsible for oversight of significant environmental, social and governance matters that are relevant to the Company.

To more effectively prevent, detect and respond to information security threats, the Company has a dedicated Chief Information Security Officer ("CISO") whose team is responsible for leading enterprise-wide information security strategy, policy, standards, architecture and processes. The CISO reports to our Executive Vice President, Chief Information and Digital Officer (“CIDO”), who reports directly to our Chief Executive Officer. The CISO and CIDO regularly review cybersecurity matters with our Chief Executive Officer and other members of senior management, including cybersecurity risks and threats and the status of our cybersecurity incident response plan and related processes relating to the prevention, detection, mitigation and remediation of cybersecurity incidents. As part of its oversight responsibility of cybersecurity risk and the overall enterprise risk management process, the Audit Committee meets at least quarterly with the Company’s CISO, the CIDO, and other senior management to receive updates on cybersecurity risks and threats (and should they arise, any material incidents), the status of initiatives to strengthen the Company’s information security systems, management’s assessments of the Company’s security program and compliance with disclosure requirements. The Audit Committee and senior management report any findings and recommendations, as appropriate to the full Board of Directors for consideration. The Company has developed and conducts mandatory information security training programs for all employees and maintains cyber liability insurance policies.

Corporate Responsibility

The Board oversees the Company’s efforts to conduct its business in a principled, transparent, and accountable manner. The Board believes that its effective oversight of environmental, social and governance matters is central to its risk oversight function. The Nominating and Governance Committee is responsible for oversight of significant matters in these areas, and the Audit and Compensation Committees are delegated responsibility for oversight of specific topics. However, the Board receives regular updates from each of the Committees and retains ultimate oversight responsibility for these matters.

Our management teams work with senior leaders to set strategy and develop goals to embed sustainability objectives across our organization. Management of our sustainability programs is led by the Executive Vice President, Supply Chain and Operations who reports at least annually to the Board and as appropriate to the Board Committees on the status of these programs.

Sustainability Initiatives

We promote ethics, safety, and environmental sustainability in conducting our business. We act responsibly and strive to reduce our environmental impact by how we service customers and the communities in which we operate. As a business-to-business distribution, logistics services, and supply chain solutions company, our approach to sustainability includes positive actions across our organization to reduce the environmental impacts of our own operations and assist our customers and suppliers with attaining their sustainability goals through our products, services, and supply chain solutions. For example, we assist our customers in areas such as lighting efficiency, energy management, renewable energy, and green sustainable sourcing. We also support utilities as they work to meet their renewable portfolio standards initiatives (solar and wind generation projects). Our lighting renovation and retrofit business is focused on improving energy efficiency in offices, schools, high rise buildings and manufacturing plants and our automation solutions are focused on reducing waste for customers.

Overall, we continue to invest in new and emerging technologies and expand our capabilities in order to meet growing demands in these areas:

Safety

Our Sustainability Goals include a focus on employee safety, training and development, as these are core values of Wesco. We work to reduce or eliminate health and safety risks through dedicated programs, leadership commitments and employee involvement. We seek to achieve continuous improvement in the safety of our facilities and track a series of metrics that provide guidance toward that improvement. We have adopted a Global Health and Safety Policy to promote a culture of operational excellence and safety, health, and environmental performance.

Inclusive and Respectful Workplace Culture

We believe that our people and our high-performance culture are our greatest assets. We foster a culture that values and rewards employees based on merit. We also believe that making the most of the wealth of ideas, talents, skills, backgrounds, and perspectives from our people helps us do more and drives value for our stakeholders. We take pride in our talented workforce and aspire to become the employer of choice in our industry. Our Compensation Committee and Board are updated routinely by management on relevant programs and engage in regular discussions on matters such as workplace culture, talent development, and employee engagement.

We require that personnel actions are administered without any form of discrimination, and in compliance with applicable law.

We aim to support an inclusive and respectful workplace culture that:

Human Rights – At Wesco, the way in which we conduct business is as important as the products and services that we provide. Our Human Rights policy includes protections relating to:

We also expect vendors to comply with our Supplier Code of Conduct, which incorporates these human rights protections.

United Nations Global Compact

Wesco’s focus on sustainability includes supporting the ten principles of the United Nations Global Compact, which we joined in 2017. We also support the United Nations Sustainable Development Goals. Our recent efforts have had the most impact for the goals below.

Prohibition on Hedging and Pledging

The Company’s Insider Trading Policy prohibits Section 16 Directors and Officers from engaging in any hedging transactions that involve Wesco securities. Wesco believes that this ensures a strong alignment of the interests of Directors and Officers with our stockholders. The policy also prohibits all Officers, Directors, Designated Insiders and employees from selling short (including short sales “against the box”) or from trading, writing, or purchasing “put” or “call” options on Wesco securities. Section 16 Directors and Officers also are prohibited from holding securities of Wesco in a margin account and from using shares as collateral and pledging them as security for a loan. Designated Insiders and employee stockholders are not prohibited from using Wesco securities as collateral to secure a bona fide loan.

Stockholder Proposals for 2027 Annual Meeting

If you wish to have a stockholder proposal included in the Company’s proxy soliciting materials for the 2027 Annual Meeting of Stockholders, you must submit the proposal to the Company at its principal executive offices by our deadline, which is 120 days prior to the first anniversary of the mailing of this Proxy Statement, or December 18, 2026. For any other business to be properly brought before the 2027 Annual Meeting by a stockholder, notice in writing must be delivered to the Company in accordance with the Company’s Amended and Restated By-Laws not less than 90 days nor more than 120 days prior to the first anniversary of the 2026 Annual Meeting, or between January 28, 2027, and February 27, 2027. We may be required to include certain limited information concerning any such proposal in our Proxy Statement so that proxies solicited for the 2027 Annual Meeting may confer discretionary authority to vote on that matter. Any stockholder proposals should be addressed to our Corporate Secretary, WESCO International, Inc., 225 West Station Square Drive, Suite 700, Pittsburgh, Pennsylvania, 15219-1122.

Board and Committee Meetings

Our Board has four standing committees: an Audit Committee, a Compensation Committee, an Executive Committee, and a Nominating and Governance Committee. Each Committee operates under a separate charter, which is available on the corporate governance section of our website at https://www.wesco.com/us/en/our-company/corporate-responsibility/governance-guidelines-and-policies.

The full Board held four meetings in 2025. Each Director attended 75% or more of the aggregate number of meetings of the full Board held in 2025 and the total number of meetings held by all Committees of the Board on which he or she served.

The membership information above reflects the composition of the Committees as of the date of this Proxy Statement. Messrs. Griffin and Raymund will retire from the Board at the end of their current term and will not stand for re-election at the 2026 Annual Meeting. Immediately following the 2026 Annual Meeting, and assuming all Director nominees are elected, the Board intends to reconstitute its Committees as follows:

Director Compensation

Compensation

Independent members of the Board of Directors receive compensation in the form of an annual cash retainer paid quarterly and an annual equity award. Directors have the ability to defer 25% to 100% of the cash and equity retainers. Deferred annual cash retainer amounts were converted into stock units and credited to an account in the Director’s name using the fair market value of our Common Stock on the dates the annual retainer would have been paid in the absence of a deferral election. The table below sets forth 2025 annual retainers for our non-employee Directors, as determined based on analysis provided by the independent compensation consultant, as described below.

The Nominating and Governance Committee works with an independent compensation consultant, Meridian Compensation Partners, LLC (“Meridian”), to do an annual assessment of Director Compensation, including providing the Nominating and Governance Committee with market research and comparison data using a peer group of companies which is the same as that used in the Compensation Committee’s evaluation of executive compensation. We review Director Compensation compared to that of the peer group. We query our consultant on new developments, best practices and trends in Director Compensation, and Meridian serves as a resource to the Nominating and Governance Committee.

In addition to the retainer, non-employee Directors are reimbursed for travel and other reasonable out-of-pocket expenses related to attendance at Board and Committee meetings. Directors receive no additional compensation for Board or Committee meeting attendance. Members of our Board who are also our employees do not receive compensation for their services as Directors.

For 2025, non-employee Directors received equity grants in the form of Restricted Stock Units ("RSUs") in the amount of $185,000, which will vest on the first anniversary of the date of the grant. If a Director’s Board service is terminated earlier than one year from the date of grant as a result of the scheduled expiration of the Director’s term then, if such date is (1) less than three calendar months from the date of grant, then 25% of the RSUs shall be deemed vested, (2) at least three but less than six calendar months from the date of grant, then 50% of the RSUs shall be deemed vested, (3) at least six but less than nine calendar months from the date of grant, then 75% of the RSUs shall be deemed vested, and (4) at least nine calendar months from the date of grant, then 100% of the RSUs shall be deemed vested. On March 1, 2025, each non-employee Director received a grant of 1,025 RSUs with a grant date fair value of $180.47 per RSU, which was the closing price of our Common Stock on February 28, 2025.

Distribution of deferred stock units will be made in a lump sum or in installments, in the form of shares of our Common Stock, in accordance with the distribution schedule selected by the Director at the time the deferral election is made.

As set forth on an exhibit to the Company’s Form 10-K filed on February 22, 2016, the Company has entered into indemnification agreements with each current Director providing for: indemnification for indemnifiable claims and losses; advancement of expenses; and D&O liability insurance.

Robust Stock Ownership Guidelines

Our Board has adopted robust stock ownership guidelines for Directors, which are five times their annual cash retainer. Directors are expected to hold these ownership positions during their service as Directors. All Directors have acquired or are acquiring stock in accordance with the stock ownership guidelines.

Director Compensation for 2025

Director Outstanding Equity Awards at Year-End

The following table summarizes outstanding RSUs held by each director on December 31, 2025, including those on which settlement has been deferred and those acquired through the deemed reinvestment of dividend equivalents.

Security Ownership

Security Ownership of Management

The following table sets forth the number of shares of Company’s Common Stock beneficially owned as of March 30, 2026, by each Director or nominee for Director of the Company, the named executive officers in the Summary Compensation Table and by all Directors and executive officers as a group. Unless otherwise indicated, the holders of all shares shown in the table have sole voting and investment power with respect to such shares. In determining the number and percentage of shares beneficially owned by each person, shares that may be acquired by such person pursuant to options or convertible stock exercisable or convertible within 60 days of March 30, 2026, are deemed outstanding for purposes of determining the total number of outstanding shares for such person and are not deemed outstanding for such purpose for all other stockholders.