If you held shares of WESCO International, Inc. (“WESCO” or the “Company”) Common Stock at the close of business on April 6, 2018, you may vote at the Annual Meeting. Each share is entitled to one vote on each matter presented for consideration and action at the Annual Meeting.

In order to vote, you must either designate a proxy to vote on your behalf, or attend the Annual Meeting and vote your shares in person. The Board of Directors requests your proxy so that your shares will count toward a quorum and be voted at the meeting.

Proposal 1—Elect eight Director nominees for a one-year term expiring at the 2019 Annual Meeting of Stockholders.

Proposal 2—Approve, on an advisory basis, the compensation of the Company’s named executive officers.

Proposal 3—Ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2018.

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.

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

The deadline for voting by Internet or telephone is 11:59 p.m., E.D.T., on Wednesday, May 30, 2018.

If you 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 “FOR” the election of each of the Director nominees named in this Proxy Statement, “FOR” the approval, on an advisory basis, of the compensation of the Company’s named executive officers, and “FOR” the ratification of the appointment of PricewaterhouseCoopers LLP as our Company’s independent registered public accounting firm for the year ending December 31, 2018.

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

If your shares are registered differently and are in more than one account (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 a broker, bank or other nominee account with respect to your shares held in “street name”. Please carefully follow the instructions on each Notice you receive and vote all of the proxy requests to ensure that all your shares are voted.

Shares held beneficially through a broker, bank or other nominee may not be voted in person at the Annual Meeting UNLESS you obtain a “Legal Proxy”. A “Legal Proxy” must be obtained from your broker, bank or other nominee that holds your shares. Without a “Legal Proxy”, you will not be able to attend and vote those shares in person at the Annual Meeting at the Hyatt Regency Pittsburgh International Airport, 1111 Airport Boulevard, Pittsburgh, Pennsylvania.

Shares registered directly in your name with our transfer agent, Computershare, may be voted in person at the Annual Meeting.

Directions to the Annual Meeting at the Hyatt Regency Pittsburgh International Airport, 1111 Airport Boulevard, Pittsburgh, Pennsylvania, are available at www.wesco.com.

Representatives of Broadridge Financial Solutions, Inc. 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.

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

If you are a “stockholder of record” 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 hold your WESCO stock in “street name” (such as through a broker, bank, or other nominee account), follow the information provided by your nominee for instructions on how to elect to receive paper copies of future Proxy Statements and Annual Reports.

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.

Holders of our Common Stock at the close of business on the record date of April 6, 2018 may vote at our Annual Meeting. On the record date, 47,042,918 shares of our Common Stock were outstanding. A list of stockholders entitled to vote will be available at the Annual Meeting at the Hyatt Regency Pittsburgh International Airport, 1111 Airport Boulevard, Pittsburgh, Pennsylvania, and during ordinary business hours for 10 days prior to the Annual Meeting at the Company’s principal executive offices. Any stockholder of record may examine the list for any legally valid purpose.

The Board of Directors is soliciting your proxy to vote at our Annual Meeting of Stockholders, and at any adjournment or postponement of the meeting. In addition to soliciting proxies by mail, telephone, and the Internet, our Board of Directors, without receiving additional compensation, may solicit in person. We have engaged Morrow Sodali LLC, 470 West Ave., Stamford, CT 06902 to assist us in the solicitation of proxies, and we expect to pay Morrow Sodali LLC approximately $8,500 for these services, plus reimbursement of their expenses. Brokerage firms and other custodians, nominees, and fiduciaries will forward proxy soliciting material to the beneficial owners of our Common Stock, held of record by them, and we will reimburse these brokerage firms, custodians, nominees and fiduciaries for reasonable out-of-pocket expenses incurred by them in doing so. The cost of this proxy solicitation will consist primarily of printing, legal fees, and postage and handling. We will pay the cost of this solicitation of proxies.

To conduct the business of the Annual Meeting, we must have a quorum. The presence, in person or by proxy, of stockholders holding at least a majority of the shares of our Common Stock outstanding will constitute a quorum. Abstentions, broker non-votes and votes withheld from Director nominees count as

shares present for purposes of determining a quorum. A broker non-vote occurs when a broker, bank or other nominee holder does not vote on a particular item because the nominee holder does not have discretionary authority to vote on that item and has not received instructions from the beneficial owner of the shares. In the absence of voting instructions from the beneficial owner of the shares, nominee holders will not have discretionary authority to vote the shares at the Annual Meeting in the election of Directors, the approval, on an advisory basis, of the compensation of the Company’s named executive officers, but will have discretionary authority to vote on the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2018. Broker non-votes will not affect the outcome of any of the matters scheduled to be voted upon at the Annual Meeting and are not counted as shares voting with respect to any other matter on which the broker has not voted expressly. Proxies that are transmitted by nominee holders for beneficial owners will count toward a quorum and will be voted as instructed by the nominee holder.

The election of Directors will be determined by a plurality of the votes cast. The Board has adopted a Director resignation policy in the event a Director receives less than 50% of the votes for his or her re-election in an uncontested election. Only votes “FOR” or “WITHHELD” affect the outcome of the election of Directors. The ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2018, and the approval, on an advisory basis, of our executive compensation will require affirmative votes by a majority of the shares present, in person or by proxy, and entitled to vote and voting on the proposal at the Annual Meeting. Abstentions will not affect the outcome of any of the matters scheduled to be voted upon at the Annual Meeting.

OUR BOARD UNANIMOUSLY RECOMMENDS A VOTE “FOR”

EACH OF THE DIRECTOR NOMINEES.

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.

We have adopted a Code of Business Ethics and Conduct and a Global Anti-Corruption 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 also have adopted a Senior Financial Executive Code of Principles for Senior Executives, referred to as the Senior Financial Executive Code, which applies to our Chief Executive Officer, Chief Financial Officer and Corporate Controller. We disclose future 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 Ethics and Conduct, Global Anti-Corruption Policy, Senior Financial Executive Code, Independence Policy, and related documents on our website at www.wesco.investorroom.com/overview.

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 categorical standards to assist it in evaluating the independence of each of its Directors. The categorical 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 categorical standards establish thresholds at which any relationships are deemed to be material.

In February 2018, the independence of each Director was reviewed, applying our independence standards. The review considered 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 affirmatively determined that the following Directors are independent: Ms. Beach Lin, Mr. Espe, Mr. Griffin, Mr. Morgan, Mr. Raymund, Mr. Singleton, and Ms. Utter.

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 are identified on pages 3 to 7.

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, and ability and willingness to commit sufficient time to Board activities. 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 diverse backgrounds and experiences. The Nominating and

Governance Committee considers candidates diverse in geographic origin, gender, ethnic background and 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 diversity of backgrounds and experiences.

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, financial expertise, capital markets expertise, sales or marketing expertise, supply chain or industry experience, mergers and acquisitions experience, international experience, technology expertise, and operational or strategy experience, among

others. 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 good overall Board composition. The Nominating and

Governance Committee applies the same criteria to all candidates that it considers, including any candidates submitted by stockholders.

The Board has established a robust self-evaluation process for the Board and its Committees. 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. Our Nominating and Governance Committee has responsibility for oversight of the Board and Committee evaluation process. In addition, the Lead Director also conducts a one on one interview with each Board member, and the Committee Chairs conduct one on one interviews with each of their respective Committee members. The results of the Board and Committee Evaluations are communicated to all Board and Committee members, and all

Board members participate in this continuous improvement process.

In 2018, as part of its continuous improvement efforts, the Board enhanced its evaluation process by engaging an independent third party. The consultant is experienced in corporate governance matters and will interview 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, the third party will seek input as to the performance of each individual Director, which the Lead Director will provide to each Director in an individual session.

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 with a longer experience with the Company, to benefit the Company and its stockholders by providing fresh perspectives, experience and stability. During the past four years, three Directors have retired and the Board has recruited new Directors and is actively engaged in the Board refreshment process, and thus 29% of our seven independent Directors have a tenure of four years or less.

In order to develop a balanced Board, the Director recruitment process included utilizing the assistance of a nationally recognized recruiting firm to identify and recruit potential Directors, based on requirements outlined on a skills matrix that was developed by the Nominating and Governance Committee. The Board has engaged an independent search firm in 2018 to further its recruitment and refreshment efforts, and the Board plans to add two new Directors.

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.

During 2017, the non-management members of our Board met in executive session at each regularly scheduled Board of Directors’ 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.

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 the structure is best for the Company at this time 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 comprised 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.

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 addresses noted in the corporate governance section of our website at www.wesco.investorroom.com under the caption “Contact Our Board.”

Our Director of Internal Audit will review all of these communications on a timely basis and 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: Director of Internal Audit.

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 2017 Annual Meeting of Stockholders.

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 containing:

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.

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.

The Board has adopted a resignation policy under which any Director who does not receive a majority of votes for his or her

re-election is expected to offer his or her resignation for the Board’s consideration.

We actively engage with our stockholders throughout the year so that management and the Board can better understand stockholder perspectives on governance, strategy, financial performance, executive compensation and other topics that are important to them, and to assess emerging issues that may help

shape our practices and enhance our corporate disclosures. We strive for a collaborative approach to stockholder engagement and value the variety of stockholders’ perspectives received. As described on page 26, we engaged in stockholder outreach related to our say on pay during 2017.

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. The Audit Committee of the Board 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. 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. The Compensation Committee of the Board 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.

If you wish to have a stockholder proposal included in the Company’s proxy soliciting materials for the 2019 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 17, 2018. For any other business to be properly brought before the 2019 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 2018 Annual Meeting, or between January 31, 2019 and March 2, 2019. We may be required to include certain limited information concerning any such proposal in our Proxy Statement so that proxies solicited for the 2019

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.

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

The full Board held four meetings in 2017. Each Director attended 75% or more of the aggregate number of meetings of the full Board held in 2017 and the total number of meetings held by all Committees of the Board on which he or she served.

During 2017, the Executive Committee consisted of Ms. Beach Lin and Messrs. Engel, Morgan, Raymund and Singleton, with Mr. Singleton serving as Chairman of the Executive Committee. With the exception of Mr. Engel, all Executive Committee members have been determined by our Board to be independent Directors according to the independence standards

of the NYSE. The Executive Committee may exercise all the powers and authority of the Directors in the management of the business and affairs of our Company and has been delegated authority to exercise the powers of our Board between Board meetings. The Executive Committee did not meet in 2017.

The members of our Nominating and Governance Committee are required to be, and were determined by our Board to be, independent under the independence standards of the NYSE. From January 2017 through March 31, 2017, the Nominating and Governance Committee consisted of Messes. Beach Lin and Utter, Mr. James J. O’Brien, who resigned from the Board effective March 31, 2017, and Mr. Singleton, with Ms. Beach Lin serving as Chair of the Nominating and Governance Committee. Following the resignation of Mr. O’Brien, the Nominating and Governance Committee consisted of Messes. Beach Lin and Utter and Mr. Singleton, with Ms. Beach Lin serving as Chair of the Nominating and Governance Committee. In December 2017,

Mr. Espe and Mr. Griffin became members of the Nominating and Governance Committee. The Nominating and Governance Committee is responsible for identifying and nominating candidates for election or appointment to our Board and determining compensation for Directors. It is also the responsibility of our Nominating and Governance Committee to review and make recommendations to our Board with respect to our corporate governance policies and practices and to develop and recommend to our Board a set of corporate governance principles. Our Nominating and Governance Committee held three meetings in 2017.

The members of our Audit Committee are required to be, and were determined by our Board to be, independent Directors according to the independence standards of the SEC and the NYSE. From January 2017 through March 31, 2017, the Audit Committee consisted of Messrs. Raymund, Espe, and Mr. O’Brien, who resigned from the Board effective March 31, 2017, and Ms. Utter, with Mr. Raymund serving as Chair of the Audit Committee. Following the resignation of Mr. O’Brien, the Audit Committee consisted of Messrs. Raymund and Espe and Ms. Utter. Our Board has determined that Messrs. Espe, and Raymund and Ms. Utter are Audit Committee Financial Experts, as defined under applicable SEC regulations. Our Audit Committee is responsible, among other things, for: (a) appointing

the independent registered public accounting firm to perform an integrated audit of our financial statements and to perform services related to the audit; (b) reviewing the scope and results of the audit with the independent registered public accounting firm; (c) reviewing with management our quarterly and year-end operating results; (d) considering the adequacy of our internal accounting and control procedures; (e) reviewing the Annual Report on Form 10-K and Quarterly Reports on Form 10-Q; and (f) reviewing any non-audit services to be performed by the independent registered public accounting firm and the potential effect on the registered public accounting firm’s independence. Our Audit Committee held twelve meetings in 2017.

The members of our Compensation Committee are required to be, and were at all times, independent Directors according to the independence standards of the SEC and the NYSE (including the enhanced independence requirements for Compensation Committee members) and is an “outside director” as defined in Section 162(m) of the Internal Revenue Code of 1986, as amended (the “Code”). During 2017, the Compensation

Committee consisted of Ms. Beach Lin and Messrs. Griffin, Morgan and Singleton, with Mr. Morgan serving as Chairman. Our Compensation Committee is responsible for the review, recommendation and approval of compensation arrangements for executive officers and for the administration of certain benefit and compensation plans and arrangements of the Company. Our Compensation Committee held five meetings in 2017.

Under the federal securities laws of the United States, the Company’s Directors, its executive officers, and any persons beneficially holding more than ten percent of the Company’s Common Stock are required to report their ownership of the Company’s Common Stock and any changes in that ownership to the SEC and NYSE. Specific due dates for these reports have been established. The Company is required to report in this

Proxy Statement any failure to file by these dates. For the year ended December 31, 2017, all such filings were made within the required time periods, based on the Company’s review of forms filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, as amended, and written representations received from such persons.

Our Company has a written policy and has implemented processes and controls in order to obtain information from our Directors and executive officers with respect to related person transactions and for then determining whether our Company or a related person has a direct or indirect material interest in the transaction, based on the facts and circumstances. Our Nominating and Governance Committee and Board review relationships and transactions between our Directors, executive officers and our Company or its customers and suppliers in order to determine whether the parties have a direct or indirect material interest. Its evaluation includes: the nature of the related person’s

interest in the transaction; material terms of the transaction; amount and type of transaction; importance of the transaction to our Company; whether the transaction would impair the judgment of a Director or executive officer to act in the best interest of our Company; and any other relevant facts and circumstances. Transactions that are determined to be directly or indirectly material to our Company or a related person are disclosed in this Proxy Statement. For the year ended December 31, 2017, there were no related party transactions to report.

OUR BOARD UNANIMOUSLY RECOMMENDS A VOTE “FOR”

APPROVAL OF THE COMPENSATION OF THE COMPANY’S NAMED EXECUTIVE OFFICERS.

This Compensation Discussion and Analysis section discusses the Company’s compensation philosophy, policies and arrangements for the 2017 year that are applicable to our Named Executive Officers (“NEOs”): John J. Engel, David S. Schulz, Diane E. Lazzaris, Robert Minicozzi and Kimberly G. Windrow. This discussion and analysis should be read in conjunction with the “Summary Compensation Table” on page 35, its accompanying footnotes and the additional tables and narrative disclosure that follow the Summary Compensation Table.

The Compensation Discussion and Analysis includes the following key sections:

Our management and our Board of Directors have consistently believed that a straightforward and transparent philosophy and approach to compensation design is fundamental to creating stockholder value. Our program comprises three main elements: (1) base salaries; (2) annual cash incentive bonuses; and (3) long-term incentive awards. We believe that this approach has enabled us to attract and retain extraordinary management talent and to deliver strong results to our stockholders.

Beginning at the Compensation Committee’s December meeting and ending in February, executive compensation is reviewed and a total compensation review is conducted regarding salary, bonus and equity awards, based on the compensation structure and philosophy described in this Compensation Discussion and Analysis section.

Pay for Performance – The annual cash incentive and long-term incentive components of our compensation program reflect our pay-for-performance philosophy. Annual cash incentive bonuses are paid upon the achievement of a set of measurable Company financial performance metrics and individual performance objectives set by the Committee. Annual equity awards are granted at the prevailing stock price on the day of the grant and only become valuable if our stock price increases over time. Our senior most management team is also incented through the grant of performance shares, which only become vested and valuable when specific performance metrics and goals are met over a three year period. We believe our performance share incentive plan encourages the achievement of long-term value creation that benefits all stockholders.

We have structured our compensation program to provide that 85% of our CEO’s total compensation opportunity is variable and 15% is fixed. And when we evaluate the long-term component of our compensation program, 80% is performance based – a combination of performance shares and stock appreciation rights, the value of which is dependent on the Company’s

profitable performance – and 20% retention focused through the awarding of restricted stock units that vest over time.

Performance shares granted to senior management covering the three year period from 2015 to 2017 were forfeited and of no value, since the Company did not meet its performance goals established under the plan for that period, as described on pages 28 and 29. This negative outcome for our senior management reflects the Board’s commitment to pay-for-performance and our commitment to align our compensation planning to our stockholders’ interests.

2017 Performance Highlights – During 2017, we returned to sales growth in all end markets and geographies, and we posted year-over-year increases in net income and earnings per share. As described in our Form 10-K filed on February 22, 2018, net income and earnings per diluted share attributable to WESCO International were $163.5 million and $3.38 per share, respectively, in 2017. Like many U.S. companies, we were affected by the enactment on December 22, 2017 of the Tax Cuts and Jobs Act of 2017 (“TCJA”), and as a result, we recorded a provisional discrete income tax expense of $26.4 million in the fourth quarter. Excluding this item, 2017 net income and earnings per diluted share attributable to WESCO International would be $189.9 million and $3.93, respectively.

Ownership Guidelines, Hedging and Clawbacks – We have stock ownership guidelines for officers and Directors, and our officers and Directors are prohibited from engaging in hedging transactions involving our stock and from pledging stock as security for loans. We have adopted a “clawback” policy to provide for recovery of incentive compensation, if any, in excess of what would have been paid to our executive officers or former executive officers in the event that the Company is required to restate financial results and also to provide for clawback of incentive compensation in the event of misconduct by an executive officer or former executive officer.

Limited Perquisites – We use perquisites on a very limited basis, and we do not provide tax gross-ups on executive-only perquisites. We have committed to not enter into any new or materially amended agreements with executive officers providing for excise tax gross-ups with respect to payments contingent upon a change in control, and we have not entered into any such agreements. We have only one pre-existing

employment agreement (entered into prior to 2010) that includes excise tax gross-ups under certain change in control circumstances.

In this Executive Summary, we describe our philosophy, approach and the way we assess our compensation practices. We believe that this process is a pillar of our high performance corporate culture and important to our ongoing success.

Structuring a balanced, fair and properly-crafted compensation program for our executive leaders is a critical component that promotes our high performance culture and contributes to our ongoing success. Our compensation philosophy begins with the recognition that our success depends on the talent of our workforce and our relationships with customers and suppliers. Our focus on consistency, service and continuous improvement are critical performance factors, and to encourage high level performance of our leaders we have constructed a compensation plan that rewards the behavior of our executives in pursuit of the following three broad goals.

The first of our philosophical tenets is to retain an excellent management team. Fielding a consistent and high performing team is critical to our success as a company. Developing and strengthening our corporate relationships with our customers and suppliers over the long-term puts us in an opportune position to grow our business intelligently and profitably. Equally important is the consistency of internal leadership in support of our corporate mission and sustaining our high performance culture.

The second philosophical goal of our compensation planning is to put the Company in a position to recruit strong leaders as we grow our business and expand our product and service offerings. We were able to recruit and retain our CEO because of our culture and a compensation package that aligned his

performance with our strategy of creating value for our customers, suppliers and stockholders. During the past several years, we have recruited other leaders at the executive leadership level who joined the Company for the same reasons. Our consistency of approach in aligning our compensation plans to our strategy has been an important reason for our recruiting and retention successes.

Finally, the third goal of our compensation plan is to reward our executives fairly and provide proper and balanced incentives for long-term value creation. Essentially, we want to provide a level of annual base compensation that is fair. When our executives perform at a level of high achievement, we reward them with attractive but capped annual cash bonus awards. In years when they perform below agreed upon standards, they may receive little or no bonus. In terms of long-term incentives, we believe that profitability metrics and the performance of our stock are appropriate measures of our performance. We believe that the opportunity to participate in the performance of our equity is a direct link between performance and pay. We reward our executives with equity incentives to align their interests with those of the stockholders and maintain ownership guidelines to instill that mindset. The value of those stock awards will only have meaning to our senior executives if they contribute to the growth in value of WESCO’s share price – a direct reflection of the Company’s operating performance.

The three central elements to our executive total compensation approach, base salary, short-term incentives and long-term incentives, are further refined by design: our base salary and short-term incentives are cash based; and our long-term incentives are equity based. Based on our objectives, we believe it is appropriate that we target our three compensation elements at approximately the 50^th percentile of companies in our peer group. The Company’s target total cash compensation and long-term incentives for the NEOs have been generally at or below the 50^th percentile of the peer group.

We use the services of an internationally recognized independent compensation consultant, Meridian Compensation Partners, LLC (“Meridian”), which provides us with research information and data. Meridian serves as a resource to our Compensation Committee (the “Committee”), providing information on new developments, best practices and trends in compensation. However, the Committee makes its own decisions, uses its own judgment and comes to its own conclusions relating to plan design and absolute determinations of total compensation rewards.

For our compensation philosophy and approach to work properly, the Committee must assess the effectiveness of our compensation programs regularly, using a variety of external and

internal resources. In conjunction with Meridian, the Committee reviews the composition of our peer group annually. We choose a large number of similarly sized companies because we believe

that those companies are representative of the talent pool that we compete with to recruit and retain talent. This approach has proven successful, as the last NEOs that we hired came from large corporations that were not direct competitors of ours and not in the distribution industry. We also believe that a large pool of comparable companies is better than choosing a smaller group to ensure a proper sample size for comparison purposes. When we engage professional search firms to assist us in identifying senior executive talent, they recruit from a set of corporations even larger than our peer group.

Our management team conducts a thorough leadership review process every year which is reviewed by the Board during our September Board meeting. Our focus on talent management is critical to our high performance culture and ongoing success. At

the September Board meeting, the entire Board and our Committee are informed of relevant issues relating to our senior management team. We are thus able to review personal development plans, actual performance, and alignment to corporate standards and expectations. From that feedback, we are able to derive a deeper understanding of whether our compensation program continues to promote our corporate objectives. We can use this information to help assess the appropriateness of our compensation approach for any individual whose compensation we review. We ask senior management to update us during the year on talent management objectives and progress made related to those objectives.

The material components of our executive compensation program are summarized in the following chart.

The Compensation Committee believes a majority of an executive’s pay should be composed of awards that are directly tied to the Company and individual employee performance. The Compensation Committee considers all elements of pay when setting awards.

85% of our CEO’s total compensation opportunity is variable, in the form of short-term and long-term compensation, and 15% is fixed, in the form of salary.

The large majority of the at-risk compensation for our CEO and other NEOs is tied to the Company’s financial and operating performance and stock price. What NEOs eventually earn from their at-risk compensation will align strongly with what stockholders earn over that same period from their investment in the Company.

Our philosophy, approach, and the manner in which we assess our compensation programs have been consistently applied since we became a public company. We intend to maintain our

high standards and make sure that the objectives and total compensation of our senior executives are aligned with the objectives of our stockholders.

Our Board has delegated to the Committee, composed entirely of individuals who are independent Directors under the independence standards of the NYSE and SEC, (including the enhanced independence requirements for compensation committee members) and “outside directors” as defined in Code Section 162(m), the responsibility of administering executive compensation and benefit programs, policies and practices. The Committee may also delegate certain matters to a subcommittee in its discretion. Annually the performance of the management team is reviewed relative to financial results and non-financial measures, including the areas of strategic and organizational development. The non-financial measures, and the progress made by the NEOs on those measures, are also reviewed by the Committee about half-way through each fiscal year at a regularly scheduled Committee meeting. Compensation levels for our NEOs are reviewed and approved on an annual basis.

Our compensation setting process for NEOs consists of the following steps:

As previously noted, the Committee also engages an independent compensation consultant to assist in reviewing its compensation practices, to provide market comparison information, and to make recommendations.

To assist in the compensation setting process, the Committee engages Meridian, an independent, internationally recognized

executive compensation consultancy firm, to provide information and advice regarding compensation and benefit levels and

incentive plan designs. Meridian is engaged by, and reports directly to, the Committee, which has the sole authority to hire or fire Meridian and to approve fee arrangements for work performed. The Committee has authorized Meridian to interact with management on behalf of the Committee, as needed in connection with advising the Committee. The Committee has assessed the independence of Meridian pursuant to SEC and NYSE rules and concluded that Meridian’s work for the Committee does not raise any conflict of interest.

In particular, the Committee retains Meridian to prepare compensation plan reviews, identify general trends and practices in executive compensation programs, assist in selecting the peer group, use market data to perform a study of the compensation of senior management at comparable and similarly-sized (by revenue) companies, and furnish its input regarding the

compensation and incentives of the Chief Executive Officer and other executives. In addition, the Committee has sought the recommendation of the Chief Executive Officer regarding the other NEOs relative to compensation adjustments and individual performance objectives he believes would be appropriate to achieve the Company’s strategic and operational goals. Our Committee meets in person or telephonically at least five times each year, and our Committee’s Chairman meets with management and our independent compensation consultant more regularly throughout the course of the year. The working relationship between the Committee and management is constructive and independent. Our Committee reports to the entire Board of Directors at every Board meeting on its activities, the research commissioned from our compensation consultant and on the Committee’s specific compensation deliberations and decisions that directly affect our executive leadership team.

The Committee reviews analyses of compensation paid by companies in our peer group through the use of marketplace compensation profiles prepared by Meridian. The peer group generally comprises comparably-sized, industrial firms, distribution companies and businesses with dispersed locales for which logistics are important, companies in industries in which asset management, in addition to operating margin, is a relevant measure of company performance, and other companies which are potential competitors for executive talent of interest to WESCO.

As part of Meridian’s independent comprehensive review of the Company’s executive compensation, the Committee selected a new data provider for use by Meridian in the analysis. The

compensation peer group that we used in 2017 was constructed using the following selection of criteria: business similarities and relevant industries, including distributors, retailers, building products, communications equipment, construction and engineering, construction materials, electrical components/equipment, industrial companies, office services and supplies, trading companies and trucking; and revenue size. Median revenue size of the compensation peer group was $7 billion, which is considered appropriate based on WESCO’s revenue size.

The compensation peer group in 2017 was comprised of the following companies:

The Committee reviews compensation practices among these companies to provide the Committee with relevant data in setting appropriate compensation levels for its NEOs. This market analysis, which is conducted by Meridian, makes it possible to evaluate and assess compensation for numerous executive positions that are not included in proxy statements or other

public filings. To adjust for a variation in size among our Company and the companies in the peer group and to get comparable data for its analysis, Meridian uses regression analysis to adjust market values for differences in company size, based on annual revenues.

The Committee reviewed the results of the 2017 stockholder advisory vote on NEO compensation and incorporated the results as one of the many factors considered in connection with the discharge of its responsibilities and in determining compensation policies and decisions for 2017. The support of our stockholder advisory vote last year was 80.4%. In addition to our regular investor relations activities, we solicited the feedback from stockholders who held over 4.6 million shares as of last year’s record date regarding their views of the Company’s executive compensation. As a result of the feedback we

received, we endeavored to augment our proxy disclosures to better explain our rationale, provide additional details and highlight important aspects of our compensation structure and pay for performance methodology. Additionally, starting in 2018 a return metric was added to our performance share metrics as described on page 31. Our profitability and return metrics are related directly to our strategy to drive profitable revenue and earnings growth, as well as the efficient use of assets to create value for our stockholders.

Base salaries are intended to provide our NEOs with a level of competitive cash compensation that is critical for retention and appropriate given their positions, responsibilities and accomplishments with the Company. Salaries for NEOs are reviewed annually. The Committee reviews detailed individual salary history for the NEOs and compares their base salaries to salaries for comparable positions at companies within our peer group. From time to time, the Committee adjusts base salaries for executive officers to reflect performance, changes in job scope, and market practices among the peer group generally based on the 50^th percentile of base salaries for comparable positions.

In determining adjustments to base salaries, the Committee considers prevailing economic conditions, base salaries of recent additions to management, performance assessments, changes in duties and responsibilities, Company performance, comparable salary practices of companies within our peer group, the recommendation of Mr. Engel (in the case of the other NEOs), and any other factors the Committee deems relevant.

Our practice is to award cash incentive bonuses for achievement of our strategic, financial, operational, and organizational development objectives. Target short-term incentives are designed to provide compensation opportunities generally approximating the 50^th percentile of the peer group and are reviewed on an annual basis.

Annually, the Company’s performance criteria and financial and operational targets are reviewed and approved by the Committee for the upcoming year. For purposes of the 2017 annual incentive programs, the performance measures for our NEOs, all of whom are corporate officers with broad-ranging responsibilities across the entire enterprise or for multiple operating and/or corporate support functions, consist of the achievement of a combination of the following metrics: Earnings Before Interest, Taxes, Depreciation and Amortization (“EBITDA”), as reported in the Form 10-K filed with the SEC on February 22, 2018 (“Our 10-K”), and “Free Cash Flow” (as reported in Our 10-K) targets, along with individual performance objectives. The performance measures we used to determine annual cash incentive bonuses for Messrs. Engel, Minicozzi, and

Schulz and Messes. Lazzaris and Windrow, the relative weightings of such measures and the related payout as a percentage of opportunity are reflected in the table below.

We believe that EBITDA is an appropriate performance measure because it relates directly to the Company’s sales growth (including organic sales growth), operating margin performance (including gross margin and cost management) and profitability. We believe that Free Cash Flow is an appropriate performance measure because it relates directly to the company’s operating performance, including the management of working capital. Each December, the Board reviews the Company’s annual operating plan, including these measures. Targets for the coming year’s Short-Term Incentives are consistent with the Board-approved annual operating plan, based on achievement levels as set forth in the table below. Additionally, the annual operating plan forms the basis of expectations that are provided to stockholders, in the form of sales and profitability expectations, as well as free cash flow generation. Thus, management’s Short-Term Incentive Plan is aligned with stockholder interests and expectations communicated to stockholders.

In addition to the quantitative metrics noted above, the Committee reviews and makes a qualitative assessment of individual performance and accomplishments as described below, and the Committee believes that a certain portion of an NEO’s overall bonus opportunity is appropriately evaluated on a qualitative basis, particularly as it relates to the accomplishment of initiatives, projects, or other personal objectives that are not purely quantitative in nature.

The Committee also considers bonus awards in the context of the overall business conditions. In 2017, the Company returned to sales growth in all end markets and geographies and posted year-over-year increases in sales, net income and earnings per share. The positive growth in sales in the second half increased accounts receivable and reduced free cash flow. Overall for our NEOs, 2017 bonus awards were below target and lower than the prior year.

With respect to the NEOs other than himself, the Chief Executive Officer makes recommendations to the Committee for the Committee’s consideration. The Committee’s review of the Chief Executive Officer’s bonus is conducted with only independent Directors, with the assistance of the independent compensation consultant, present.

Based on Mr. Engel’s base salary of $1,000,000 for the year and a target incentive payout percentage opportunity of 135%, his target bonus opportunity was $1,350,000. His actual bonus was $1,156,639, or 86% of target. The total was calculated as follows: $1,350,000 x ((50% EBITDA)(80.2% payout) + (25% Free Cash Flow)(0% payout)) + ($615,000, or 91% of his opportunity of $675,000 for individual performance). His individual performance component was based on the Committee’s assessment of Mr. Engel’s performance regarding strategy development and execution, information technology strategy development, organizational development and talent

management, investor and corporate relations, and Board and overall leadership.

Based on Mr. Schulz’s base salary of $525,000 for three months of the year and $540,000 for nine months of the year and a target incentive payout percentage opportunity of 75%, his target bonus opportunity was $402,188. His actual bonus was $350,000, or 87% of target. The total was calculated as follows: $402,188 x ((50% EBITDA)(80.2% payout) + (25% Free Cash Flow)(0% payout)) + ($188,637, or 94% of his opportunity of $201,094 for individual performance). His individual performance component was based on the Committee’s assessment of Mr. Schulz’s achievement of objectives, including strengthening the Company’s capital structure, effective investor relations, risk management and leadership and development of the finance function.

Based on Ms. Lazzaris’ base salary of $450,000 for three months of the year and $460,000 for nine months of the year and a target incentive payout percentage opportunity of 60%, her target bonus opportunity was $274,500. Her actual bonus was $235,000, or 86% of target. The total was calculated as follows: $274,500 x ((50% EBITDA)(80.2% payout) + (25% Free Cash Flow)(0% payout)) + ($124,867, or 91% of her opportunity of $137,250 for individual performance). Her individual performance component was based on the Committee’s assessment of Ms. Lazzaris’ performance regarding legal services and contracts, aligning legal department strategy with Company strategy, talent management, supporting business growth while managing cost and productivity, enterprise risk management, and legal department leadership.

Based on Mr. Minicozzi’s base salary of $325,000 for three months of the year and $340,000 for nine months of the year and a target incentive payout percentage opportunity of 50%, his target bonus opportunity was $168,125. His actual bonus was $150,000, or 89% or target. The total was calculated as follows: $168,125 x ((50% EBITDA)(80.2% payout) + (25% Free Cash

Flow) (0% payout)) + ($82,546, or 98% of his opportunity of $84,063 for individual performance). His individual performance component was based on the Committee’s assessment of Mr. Minicozzi’s performance regarding information technology, including master data management, technology strategy development, strengthening of existing systems (including cyber security improvements), support of e-Commerce initiatives, and expansion of business intelligence capabilities.

Based on Ms. Windrow’s base salary of $410,000 for three months of the year and $420,000 for nine months of the year and a target incentive payout percentage opportunity of 60%, her target bonus opportunity was $250,500. Her actual bonus was $215,000, or 86% of target. The total was calculated as follows: $250,500 x ((50% EBITDA) (80.2% payout) + (25% Free Cash Flow) (0% payout)) + ($114,496, or 91% of her opportunity

of $125,250 for individual performance). Her individual performance component was based on the Committee’s assessment of Ms. Windrow’s performance regarding development of the human resources function, recruitment of key executive positions, improving enterprise employee engagement, leading various talent management initiatives, diversity and inclusion strategy and refinement of compensation plans.

The Committee retains the right to increase or decrease performance objectives or to make adjustments to annual incentive awards to reflect acquisitions, changes in responsibility, external changes, or changes in business conditions that have a material impact on the fairness of the previously established performance factors.

The purpose of long-term incentives is to carefully align compensation with stockholder value creation, and thus long-term incentives comprise the centerpiece of executive compensation and a significant majority of our NEOs total compensation opportunity. The final measure of the increase in stockholder value is stock price appreciation, and this principle is as simple as it is essential to understanding our philosophy and the structure of our long-term incentive arrangements.

Structure of Long-Term Incentives

Long-term incentives for our NEOs are 80% performance-based. Specifically, the grant date value of our long-term incentive awards for our NEOs is allocated as follows:

Performance-Based Elements

SARs (50%)

We use SARs to both motivate and align management’s incentives with long-term stockholder value. We believe strongly that management should have a substantial stake in the success

of the Company and that enduring stock price growth reflects the effectiveness of management in executing a long-term strategic plan, not just the passage of time. Our SARs settle in Company common stock upon exercise, and they vest ratably over three years.

Performance Shares (30%)

Our performance shares are designed to reward our NEOs for both internal drivers of long-term value and a reflection of superior stockholder value.

Specifically, performance shares are earned based on two equally weighted performance metrics. From 2015 to 2017, those metrics were: (1) Net Income Growth; and (2) Relative TSR vs. a peer group. The “Net Income Growth rate” is equal to our net income (as reported in our Form 10-Ks), excluding certain items that are not indicative of ongoing results. We believe that Net Income Growth is related directly to our strategy to drive profitable revenue and earnings growth and that enduring stock price performance reflects the effective execution of a long-term strategic plan. Each year the Committee reviews the metrics, and as described on page 31, starting in 2018 the Committee introduced a return metric in addition to a profitability metric for the performance shares.

Performance share awards vest in the form of a number of shares of the Company’s common stock, and our performance shares are measured over a three-year performance period. The number of performance shares actually earned, if any, will depend on the attainment of certain levels (threshold, target, maximum) of the performance measures and may range from one-half the target amount of performance shares (at the threshold performance level) up to two times the target amount of performance shares (at the maximum performance level). In the event of a Change in Control (as defined in the Company’s Long-Term Incentive Plan), the performance shares will vest at the target level.

Consistent with our pay-for performance philosophy, performance shares awarded in 2015 for the three-year performance period ended December 31, 2017 (the “2015

Performance Shares”) were forfeited because the performance goals were not met, as shown below.

Fundamentally, RSUs are meant to balance the need for long-term retention of key executive talent while nevertheless aligning realizable value with changes in stockholder wealth. Restricted stock is common in the marketplace and therefore is an important component of a competitive compensation opportunity. It is, however, intentionally only a modest portion of our NEOs’ total long-term incentive compensation as we put the preponderance of the weighting on the performance-based SARs and performance shares. Our RSUs cliff vest after three years.

Our philosophy is to grant equity-based long-term incentives having an economic value which generally approximates the 50th percentile of grants by companies in our peer group. We believe this target allows us to attract, motivate and retain the executive talent necessary to develop and execute our business strategy.

The Company’s target long-term incentives for the NEOs were generally at the 50th percentile of the peer group for 2017.

In 2017, we granted 455,807 SARs, 39,978 performance shares, and 87,481 RSUs in the aggregate to all award recipients. The awards were approximately equal to 1% of the weighted average outstanding stock of the Company. With respect to the NEOs other than himself, the Chief Executive Officer makes grant recommendations based on each individual executive’s expected long-term contributions to the value creation of the Company and consideration of market data. The Chief Executive Officer’s recommendations and Meridian’s analysis are considered in making grant determinations. With respect to the Chief Executive Officer, the Compensation Committee determines (without the input of the Chief Executive Officer) the amount of his grant. In 2017, we granted performance shares, SAR and RSU awards to approximately 168 employees.

Pay for performance is the paramount principle of executive compensation. However, the “Summary Compensation Table” on page 35 reflects the value of equity awards on the grant date, not their earned or realized value. Since long-term incentives comprise the significant majority of total compensation, this form of reporting obscures the degree of alignment between pay and performance. Earned and realized values substantially reflect performance.

To illustrate this impact, consider the value of the long-term incentive grant to the CEO in 2015 and the subsequent earned or realized value in 2017. The graph below depicts the 2015 grant date fair value as reported in the 2015 Summary Compensation Table and the earned or realized value of these awards three years later:

Starting with the 2018 grant of performance share awards, we base the performance share awards on two equally-weighted performance measures of the three-year average growth rate of the Company’s fully-diluted earnings per share (EPS Growth) and return on net assets (RONA) improvement. Consistent with feedback we have received from investors, we have included a return metric.

We believe that EPS Growth is an appropriate performance measure because it is aligned with the interests of stockholders

and relates directly to the Company’s profitable growth, which encompasses sales growth (including organic sales growth), operating margin expansion, and cost management.

We believe that RONA is an appropriate measure of performance because it relates directly to the Company’s focus to improve both profitability and the efficient use of operating assets (working capital, property, buildings and equipment) to create value for our stockholders.

Our Insider Trading Policy prohibits our Directors and NEOs from engaging in hedging transactions involving Company securities

and from pledging Company securities as collateral for loans.

Our Company maintains a 401(k) Retirement Savings Plan for all eligible employees, including the NEOs. In 2017, the Company matched employee contributions at a rate of $0.50 per $1.00 of

contributions up to 6% of eligible compensation. The Company did not make a discretionary payment in 2017 for the plan year ended in December 2016.

We also maintain an unfunded nonqualified deferred compensation plan for a select group of qualifying management or highly compensated employees, including the NEOs. Participants may defer a portion of their salary and are eligible for a Company match at a rate of $0.50 per $1.00 up to 6% of eligible compensation less any Company match paid under the 401(k) plan. Earnings are credited to employees’ accounts based

on their deemed investment selections from offered investment funds. Notwithstanding any provision of the Deferred Compensation Plan or benefit election made by any participant deemed to be a key employee, benefits payable under the Deferred Compensation Plan will not commence until at least six months after the key employee’s separation from employment. See the “Nonqualified Deferred Compensation” table on page 40 for more information regarding the NEOs’ benefits under the Deferred Compensation Plan.

Our Company does not have a defined benefit or supplemental retirement plan or any plans providing for post-retirement health benefits for our NEOs.

We provide health benefits to full-time employees, including the NEOs, who meet the eligibility requirements. Employees pay a

portion of the cost of healthcare on an increasing scale correlated to higher annual incomes. Accordingly, the NEOs’

percentage share of the cost of benefit coverage under our plan is higher than other employees. Our health and welfare benefits are evaluated periodically by external benefits consultants to assess plan performance and costs and to ensure that benefit

levels approximate the median value provided to employees of peer companies. As a risk management measure, we also offer executive physicals involving diagnostic testing.

During 2017, the Company provided a limited number of perquisites to the NEOs. They primarily consist of a vehicle allowance, club memberships and spousal travel to certain business functions. The Compensation Committee determined that it is in the Company’s best interest to continue providing

these perquisites in order to offer a competitive pay package. The Company does not provide tax gross-ups on executive-only perquisites. See the “All Other Compensation” table on page 36 for more information regarding the perquisites given to our NEOs.

We have adopted a “clawback” policy to provide for recovery of incentive compensation, if any, in excess of what would have been paid to our executive officers or former executive officers in the event that the Company is required to restate financial results

and also to provide for clawback of incentive compensation in the event of misconduct by an executive officer or former executive officer.

Our Board has adopted stock ownership guidelines for certain executive officers. For the NEOs, the ownership guidelines are as follows:

These officers are expected to acquire their initial ownership positions within five years of their appointment and to hold those

ownership positions during their service as executives of the

Company. Until the stock ownership guidelines are met, an officer must hold a minimum of 50% of the pre-tax value realized at the exercise or vesting of equity awards. All of our NEOs have acquired or are acquiring equity in accordance with the guidelines. See “Security Ownership” on page 16 for more information on their ownership positions. See also “Director Compensation” on page 48 for information about Stock Ownership Guidelines for Directors. In addition, the Company has stock ownership guidelines for other officers and members of management who are not NEOs. In total, approximately 34 individuals were subject to stock ownership guidelines as of April 2018.

Mr. Engel’s compensation is higher than the compensation of other NEOs due to the broad scope of his responsibilities as Chief Executive Officer, including executive leadership in the development, articulation and promotion of the Company’s vision, goals and values, the development and execution of the Company’s long-term strategy and annual operating and financial plans, the development and motivation of the senior management team, ensuring the recruitment, training

and development of the required human resources to meet the needs of the Company, and overall service as the principal spokesperson for the Company in communicating with stockholders, employees, customers, suppliers, and our Board and Board committees. During the year, Mr. Engel’s target total compensation for 2017 (the total of salary, target annual cash incentive and long-term incentives) was slightly above the 50^th percentile of the Company’s peer group.

Mr. Engel has a 2009 Employment Agreement that provides for, among other things, an initial annual base salary of $725,000 with a target bonus of not less than 100% of base salary, as may be adjusted by the Compensation Committee, Mr. Engel also

receives long-term equity-based incentives under the Company’s Long-Term Incentive Plan as determined by the Committee. In the event that prior to a change in control Mr. Engel’s employment is terminated by the Company without cause or by Mr. Engel for

good reason, he will be entitled to receive monthly cash payments for 24 months in an amount equal to his monthly base salary as of the termination date, a lump sum cash amount equal to his target annual incentive opportunity for the year in which he was terminated and accelerated vesting of all stock-based awards, exercisable for up to 18 months, except for performance based awards where operational or performance criteria have not been met. If such termination occurs within two years after a change in control, Mr. Engel will instead be entitled to receive (i) a lump sum cash payment equal to two times the sum of his annual base salary and his annual target incentive opportunity as of the termination date, (ii) a gross-up payment to offset certain excise taxes, if any, (iii) prorated incentive compensation for the year in which he was terminated and (iv) accelerated vesting of all stock-based awards, exercisable for up to 18 months, except for performance-based awards where operational or performance criteria have not been met. As disclosed previously, other than the pre-existing employment agreement with Mr. Engel, the Company has no other agreements with executive officers providing for excise tax gross-ups with respect to payments contingent upon a change in control. In addition, the Company committed that it will not enter into any new or materially amended agreements with executive officers providing for excise tax gross-ups with respect to payments contingent upon a change in control and, indeed, has not entered into any such agreements. See “Potential Payments Upon Termination” on page 41 for additional information. The 2009 employment agreement has a term of three years and thereafter is subject to one-year automatic extensions. Mr. Engel is subject to confidentiality obligations during the term of his employment and for five years thereafter. He is bound by restrictive covenants in the form of non-competition and non-solicitation of employees and customers during the term of his employment and for a period of two years thereafter.

Mr. Schulz would be entitled to receive a severance payment equal to one year’s base salary plus pro rata bonus if he is terminated by the Company without cause, if he terminates his employment for good reason, or if his employment is terminated by the Company upon or within two years after a change in control of the Company, as described on page 43. Mr. Schulz is bound by restrictive covenants in the form of non-competition and non-solicitation of employees during the term of his employment and for a period of one year thereafter.

Ms. Lazzaris would be entitled to receive a severance payment equal to one year’s base salary plus pro rata bonus if she is

terminated by the Company without cause, if she terminates her employment for good reason, or if her employment is terminated within one year following a change in control of the Company (other than for cause), as described on page 44.

Mr. Minicozzi would be eligible to receive a payment equal to one year’s base salary of severance if he is terminated by the Company without cause, or he terminates his employment for good reason, as described on page 45. Mr. Minicozzi is bound by restrictive covenants in the form of noncompetition and nonsolicitation of employees during his term of his employment and for a period of one year thereafter.

Ms. Windrow would be entitled to receive a severance payment equal to one year’s base salary plus pro rata bonus if she is terminated by the Company without cause, or she terminates her employment for good reason, as described on page 46. Ms. Windrow is bound by restrictive covenants in the form of non-competition and non-solicitation of employees during the term of her employment and for a period of one year thereafter.

The Company’s LTIP provides that SAR and RSU awards would vest upon consummation of a Change in Control transaction, and our performance share award agreements provide that performance share awards would vest at the target level upon consummation of a Change in Control transaction. The payments to the NEOs upon consummation of a Change in Control transaction for accelerated vesting of equity awards are set forth in the first column of each table on pages 41 to 46.

We maintain the WESCO Distribution, Inc. 2006 Severance Plan which provides severance benefits to all eligible employees, not limited to executives. In accordance with the WESCO Distribution, Inc. 2006 Severance Plan, in the event of an involuntary termination without cause, an eligible employee would receive severance payments of up to 52 weeks of base pay based on the employee’s completed years of service.

As set forth on an exhibit to the Company’s Form 10-K filed on February 22, 2017, the Company has entered into indemnification agreements with Messrs. Engel and Schulz and Messes. Lazzaris and Windrow providing for: indemnification for indemnifiable claims and losses; advancement of expenses; and D&O liability insurance.

On an annual basis, the Committee reviews the potential for risk regarding our compensation program design, including incentive compensation. The Committee has reviewed the Company’s compensation programs for employees generally and has concluded that these programs do not create risks that are reasonably likely to have a material adverse effect on the Company. The Committee believes that the design of the Company’s annual cash and long-term equity incentives provides an effective and appropriate mix of incentives to help

ensure the Company’s performance is focused on long-term stockholder value creation and does not encourage the taking of short-term risks at the expense of long-term results. Short-term incentive award payouts to the NEOs are subject to review and approval of the Committee, and the Committee also reviews with the independent members of the Board the CEO’s incentive award. The Committee has the discretionary authority to reduce or eliminate any incentive payouts. As previously noted above, the Company also maintains stock ownership guidelines and has

adopted a clawback policy that applies to incentive compensation, if any, in excess of what would have been paid to our executive officers or former executive officers in the event

that the Company is required to restate financial results and also to provide for clawback of incentive compensation in the event of misconduct by an executive officer or former executive officer.

Management succession planning and talent development are reviewed by the Board annually as part of its leadership and organizational review process. The Board reviews and discusses with management succession plans for the NEOs and other senior management positions across the Company, and the Board also evaluates succession plans in the context of overall Company strategy. Senior management is visible to Board members through formal presentations and informal events to

allow Directors to personally assess candidates. The Board also establishes steps to address emergency CEO succession planning in extraordinary circumstances. The emergency CEO succession planning is intended to help the Company respond in the event of an unexpected emergency and reduce potential disruption or loss of continuity to the Company’s business and operations.

We consider the anticipated accounting and tax treatment to the Company and our executive officers when reviewing executive compensation and our compensation programs, but the Company reserves the right to pay compensation that is not deductible and a portion of the executive officers’ compensation paid in 2017 was not deductible. The deductibility of some types of compensation payments can depend upon the timing of an executive’s vesting or exercise of previously granted rights or termination of employment.

Code Section 162(m) generally imposes a $1 million limit on the amount that a public company may deduct for compensation paid to the Company’s CEO and certain other highly compensated executive officers (together, the “covered employees”). The TCJA repealed, effective for tax years beginning after December 31, 2017, the exception to the

Section 162(m) limitation for compensation that met the requirements for “qualified performance-based” compensation (i.e., compensation paid only if the individual’s or the Company’s performance meets pre-established objective goals based on stockholder-approved performance criteria). Therefore, compensation paid to our covered employees in excess of $1 million per year will not be tax deductible after December 31, 2017, unless it qualifies for the transition relief provided by the TCJA for compensation paid pursuant to a binding written contract which was in effect on November 2, 2017 and not materially modified on or after that date. As a result of uncertainty about the application of the transition provisions, it is unclear whether compensation in excess of $1 million paid to a covered employee that had been intended to be qualified performance-based compensation will be deductible.

The Compensation Committee has reviewed and discussed the foregoing Compensation Discussion and Analysis with management and, based on that review and those discussions, it recommended to the Board of Directors that the foregoing Compensation Discussion and Analysis be included in our Proxy Statement, and incorporated by reference in our Annual Report on Form 10-K for the year ended December 31, 2017.

Respectfully Submitted:

THE COMPENSATION COMMITTEE

John K. Morgan, Chairman

Sandra Beach Lin

Bobby J. Griffin