UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

Information Required in Proxy Statement

Schedule 14A Information

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.      )

Filed by the Registrant      þ☑

Filed by a Party other than the Registrant      ¨☐

Check the appropriate box:

April 29, 2016May 1, 2017

Dear Stockholder:

You are cordially invited to attend the 20162017 Annual Meeting of Stockholders (the “Annual Meeting”) of Vicor Corporation (the “Corporation”). The Annual Meeting will be held at the following date, time, and location:

The attached Notice of Annual Meeting and Proxy Statement cover the formal business of the Annual Meeting and contain a discussion of the matters to be voted upon at the Annual Meeting. At the Annual Meeting, the Corporation’s management also will report on the operations of the Corporation and be available to respond to appropriate questions from stockholders.

The Board of Directors encouragesWe hope you will be able to promptly complete, date, sign,attend the Annual Meeting, but in any event we would appreciate your completing, dating, signing, and returnreturning your Proxy CardCard(s) as soonpromptly as possible. If you attend the Annual Meeting and wish to vote your shares in person, you may revoke your proxy at that time.

Sincerely yours,

PATRIZIO VINCIARELLI Chairman of the Board, President and Chief Executive Officer

VICOR CORPORATION

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON FRIDAY, JUNE 17, 201616, 2017

NOTICE IS HEREBY GIVEN that the 20162017 Annual Meeting of Stockholders (the “Annual Meeting”) of Vicor Corporation, a Delaware corporation (the “Corporation”), will be held on Friday, June 17, 2016,16, 2017, at 9:00 a.m., local time, at the offices of Foley & Lardner LLP, 111 Huntington Avenue, Boston, Massachusetts 02199, for the following purposes:

1.   To fix the number of Directors at 10nine and to elect the 10nine nominees named in the attached proxy statement as Directors to hold office until the 20172018 Annual Meeting of Stockholders and until their respective successors are duly elected and qualified, andqualified.

2.   To hold an advisory vote on compensation of the Corporation’s named executive officers.

3.   To hold an advisory vote on the frequency of stockholder votes on executive compensation.

4.   To approve the amendment and restatement of the Vicor Corporation Amended and Restated 2000 Stock Option and Incentive Plan to increase the number of shares of common stock available for issuance thereunder from 4,000,000 to 10,000,000 shares.

5.   To approve the VI Chip Corporation Amended and Restated 2007 Stock Option and Incentive Plan.

6.   To approve the Picor Corporation Amended and Restated 2001 Stock Option and Incentive Plan.

7.   To approve the Vicor Corporation 2017 Employee Stock Purchase Plan.

8.   To consider and act upon any other matters that may be properly brought before the Annual Meeting and at any adjournments or postponements thereof.

Any action may be taken on the foregoing matters at the Annual Meeting on the date specified above, or on any date or dates to which, by original or later adjournment, the Annual Meeting may be adjourned or to which the Annual Meeting may be postponed.

The Board of Directors has fixed the close of business on April 29, 2016,28, 2017, as the record date for determining the stockholders entitled to receive notice of and to vote at the Annual Meeting and any adjournments or postponements thereof. Only stockholders of record at the close of business on April 29, 201628, 2017 will be entitled to receive notice of and to vote at the Annual Meeting and any adjournments or postponements thereof.

You are requested to authorize a proxy to vote your shares by completing, dating, and signing the enclosed Proxy Card,Card(s), which is being solicited by the Board of Directors, and by mailing it promptly in the enclosed postage-prepaid envelope. Any proxy may be revoked by delivering a written declaration deliveredrevocation to the CorporationCorporation’s Secretary stating that the proxy is revoked or by delivery of a properly executed, later dated proxy. Stockholders of record who attend the Annual Meeting may vote in person by notifying our Corporate Secretary, even if they have previously delivered a signed Proxy Card.

By Order of the Board of Directors

James A. Simms Corporate Secretary

Andover, Massachusetts

April 29, 2016May 1, 2017

VICOR CORPORATION

25 FRONTAGE ROAD

ANDOVER, MASSACHUSETTS 01810

TELEPHONE(978) 470-2900

PROXY STATEMENT

FOR THE 20162017 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON FRIDAY, JUNE 17, 201616, 2017

April 29, 2016May 1, 2017

This Proxy Statement is furnished in connection with the solicitation of proxies by the Board of Directors (the “Board” and each member thereof being a “Director”) of Vicor Corporation (the “Corporation”) from owners of the outstanding shares of capital stock of the Corporation (the “Stockholders”, or as an individual, a “Stockholder”) for use at the 20162017 Annual Meeting of Stockholders (the “Annual Meeting”) of the Corporation to be held on Friday, June 17, 2016,16, 2017, at 9:00 a.m., local time, at the offices of Foley & Lardner LLP, 111 Huntington Avenue, Boston, Massachusetts 02199, and at any adjournments or postponements thereof. At the Annual Meeting, Stockholders will be asked to consider and vote on the election of the 10 individuals namedproposals set forth in the proxy statement as Directorsthis Proxy Statement and to consider and act on any other matters that may be properly brought before the Annual Meeting and at any adjournments or postponements thereof.

In this Proxy Statement, we refer to Vicor Corporation as “Vicor,” “the Corporation,” “we,” “us,” or “our.” In addition, the term “Proxy Solicitation Materials” includes this Proxy Statement, the Notice of Annual Meeting, and the Proxy Card.Cards.

The Proxy Solicitation Materials are first being sent to Stockholders of record on or about May 9, 2016.8, 2017. The Board has fixed the close of business on April 29, 201628, 2017 as the record date for the determination of Stockholders entitled to receive notice of and to vote at the Annual Meeting (the “Record Date”). Only Stockholders of record at the close of business on the Record Date will be entitled to receive notice of and to vote at the Annual Meeting.

As of March 31, 2016,2017, there were 27,037,32827,346,172 shares of Common Stock and 11,758,218 shares of Class B Common Stock of the Corporation outstanding and entitled to vote. Each share of Common Stock entitles the holder thereof to one vote per share (for an aggregate of 27,346,172 votes), and each share of Class B Common Stock entitles the holder thereof to 10 votes per share.share (for an aggregate of 117,582,180 votes).Shares of Common Stock and Class B Common Stock will vote together as a single class, reflecting their respective voting entitlement, on each proposal at the Annual Meeting.

Stockholders are requested to complete, date, sign, and return the accompanying Proxy CardCard(s) in the enclosed postage-prepaid envelope. Shares represented by a properly executed Proxy Card received prior to the vote at the Annual Meeting and not revoked will be voted at the Annual Meeting as directed on the Proxy Card. If a properly executed Proxy Card is submitted and no instructions are given, the shares so represented will be voted FOR each of the electionDirector nominees, FOR an advisory vote on executive compensation every three years and FOR each of each individual candidate nominated for election as a Directorthe other proposals set forth herein (individually, a “Nominee”, and collectively, “Nominees”).in this Proxy Statement. We do not anticipate any matters other than those set forth in this Proxy Statement will be presented at the Annual Meeting. If other matters are properly presented, proxies will be voted in accordance with the discretion of the proxy holders.

A Stockholder of record may revoke a proxy at any time before it has been exercised by: (1) delivering a written revocation to our Corporate Secretary, James A. Simms, at the address of the Corporation set forth above; (2) filing a duly executed Proxy Card bearing a later date; or (3) appearing in person, notifying the Corporate Secretary of such revocation, and voting by ballot at the Annual Meeting. Any Stockholder of record as of the

Record Date attending the Annual Meeting may vote in person whether or not a proxy has been previously submitted, but the presence (without further action) of a Stockholder at the Annual Meeting will not constitute revocation of a previously submitted proxy.

The presence, in person or by proxy, of Stockholders representing a majority in interest of all capital stock issued, outstanding, and entitled to vote at the Annual Meeting shall constitute a quorum for the transaction of business at the Annual Meeting. Because of his ownership of shares of Class B Common Stock and shares of Common Stock, representing 82.8%82.6% of the total voting shares, a quorum is assured by the presence of Dr. Patrizio Vinciarelli, Chairman of the Board, President, and Chief Executive Officer, who will preside over the Annual Meeting. Shares that reflect abstentions or “brokernon-votes” (i.e., shares held by investment brokerage firms or other nominees that are represented at the Annual Meeting, but, as to which, such brokers or nominees have not received instructions from the beneficial owners or persons entitled to vote such shares and, with respect to one or more but not all matters, such brokers or nominees do not have discretionary voting power to vote such shares) will be counted for purposes of determining whether a quorum is present for the transaction of business at the Annual Meeting.

The cost of solicitation of proxies in the form enclosed herewith will be borne by the Corporation. In addition to the solicitation of proxies by mail, Directors, officers, and employees of the Corporation also may solicit proxies personally or by telephone,e-mail, or other form of electronic communication without special compensation for such activities. The Corporation also will request those holding shares in their names or in the names of their nominees that are beneficially owned by others to forward proxy materials to and obtain proxies from such beneficial owners. The Corporation will reimburse such holders for their reasonable expenses in connection therewith.

The Corporation’s 20152016 Annual Report (the “Annual Report”), including financial statements for the fiscal year ended December 31, 2015,2016, will be mailed to Stockholders concurrently with this Proxy Statement. The Annual Report, however, is not part of the Proxy Solicitation Materials. The Corporation and certain intermediaries (e.g., banks, brokers, and nominees) may deliver only one copy of the Annual Report and Proxy Solicitation Materials to Stockholders sharing an address. The Corporation will deliver promptly, upon written or oral request, a separate copy of the Annual Report or Proxy Solicitation Materials, as applicable, to a Stockholder at a shared address. In order to receive such a separate document, please contact our Corporate Secretary, Mr. Simms, at the address of the Corporation set forth above. If Stockholders sharing an address (i) currently receive a single copy of the Annual Report and Proxy Solicitation Materials and wish to receive separate copies of such materials in the future or (ii) currently receive separate copies of the Annual Report and Proxy Solicitation Materials and wish to receive a single copy of such materials in the future, please contact Mr. Simms, our Corporate Secretary, or the applicable intermediary, as the case may be.

PROPOSAL ONE

ELECTION OF 10NINE DIRECTORS

In accordance with the requirements of the Corporation’sBy-Laws, the Board recommends the number of Directors be fixed at 10nine and has nominated all of the Nominees named below for election to the Board. Each of the 10nine Nominees presently serves as a Director. Mr. Riddiford, a current independent Director, informed the Board he would not stand forre-election at the Annual Meeting following his 33 years of service to the

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Corporation. Accordingly, Mr. Riddiford will cease his service as a Director and as a member of the Audit Committee and the Compensation Committee following the election of directors at the 2017 Annual Meeting. After consideration of a number of factors, the Board concluded the vacancy that would be created due to Mr. Riddiford’s pending retirement would not be filled, and the number of Directors would be reduced at the Annual Meeting to nine from 10.

If elected, each Nominee will serve until the 20172018 Annual Meeting of Stockholders and until his respective successor is duly elected and qualified or until his death, resignation, or removal. Properly executed Proxy Cards will be voted FOR the Nominees unless otherwise specified. Each Nominee has consented to stand for election and the Board anticipates each of the Nominees, if elected, will serve as a Director.

However, if any person nominated by the Board is unable to serve or, for good cause, will not serve, proxies solicited hereby will be voted for the election of another person designated by the Board, if one is nominated.

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A plurality of the votes cast for a Nominee by the Stockholders of Common Stock and Class B Common Stock, voting together as a single class, shall elect such Nominee. Accordingly, abstentions, brokernon-votes, and votes withheld from any Nominee will have no effect on this proposal. There is no cumulative voting.

Because the number of incumbent Directors standing for reelection (i.e., 10)nine) is equal to the number of Nominees, and the Corporation’sBy-Laws provide for election by plurality, any number of votes cast for a Nominee assures that Nominee of election as a Director. Dr. Vinciarelli beneficially owned, as of March 31, 2016,2017, 9,828,272 shares of Common Stock and 11,023,648 shares of Class B Common Stock, together representing 82.8%82.6% of the voting power of the outstanding stock of the Corporation, sufficient to elect each of the nomineesNominees named below. He has stated an intention to vote in favor of fixing the number of Directors at 10nine and in favor of the election of all Nominees.

Information Regarding Nominees and Qualifications

The following sets forth certain information as of March 31, 2016,2017, with respect to the 10nine Nominees for election to the Board. The information presented includes information each Director has provided us about age, all positions held, principal occupation and business experience for the past five years, and the names of other publicly-held companies for which the Director currently serves as a director or has served as a director during the past five years. In addition to the information presented below regarding each Nominee’s specific experience, qualifications, and skills that led the Board as a whole to conclude the Nominee possessed the necessary attributes to serve as a Director. In addition to the experience, qualifications and skills of each Director, the Board as a whole also consideredconsiders each Nominee’s reputation for integrity, honesty, and adherence to high ethical standards.

Information regarding the beneficial ownership of shares of the capital stock of the Corporation by such persons is set forth in the section of this Proxy Statement entitled “Principal and Management Stockholders.” See also “Certain Relationships and Related Transactions.” There is no family relationship among any of the Directors and/or executive officers of the Corporation.

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The Board unanimously recommends a vote FOR fixing the number of Directors at 10nine and the election of all of the Nominees.

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CORPORATE GOVERNANCE

Status as a Controlled Company

As of March 31, 2016,2017, there were 27,037,32827,346,172 shares of Common Stock and 11,758,218 shares of Class B Common Stock of the Corporation outstanding and entitled to vote. Our Common Stock is listed for trading on the NASDAQ Global Select Market(“NASDAQ-GS”) and, as such, we are subject to the listing requirements set forth in the Marketplace Rules of the NASDAQ Stock Market LLC (the “Nasdaq Rules”). The Corporation is a “controlled company” in accordance with the governance provisions of the Nasdaq Rules, because Dr. Vinciarelli, Chairman of the Board, President, and Chief Executive Officer, holds more than 50% of the voting power of our outstanding capital stock. Accordingly, the Corporation relies on certain exemptions from corporate governance requirements available to us under the Nasdaq Rules for a controlled company.

Dr. Vinciarelli owned, as of March 31, 2016,2017, 9,828,272 shares of our Common Stock and 11,023,648 shares of our Class B Common Stock. Each share of Class B Common Stock, which entitles the holder thereof to 10 votes per share, is exchangeable on a one for one basis into a share of Common Stock, which entitles the holder thereof to one vote per share. As of March 31, 2016,2017, Dr. Vinciarelli owned 35.9%35.4% of our Common Stock and 93.7% of our Class B Common Stock, which together represent 82.8%82.6% of total voting power, giving him effective control of our governance.

Because of the Corporation’s status as a controlled company, we are not required to comply with listing standards requiring a majority of independent Directors on our Board, the determination of the compensation of our executive officers solely by independent Directors, and the recommendation of nominees for Director solely by independent Directors. Upon consideration of the independence criteria under the Nasdaq Rules, the Board has determined that four of our current 10 Directors (Messrs. Carlson, Eichten, Griffin and Riddiford) and three of our Nominees (Messrs. Carlson, Eichten, and Griffin) are independent as defined by the Nasdaq Rules. As noted above, Mr. Riddiford will not be standing forre-election to the Board at the 2017 Annual Meeting and his service as a Director and as a member of the Audit and Compensation Committees will cease following the election of Directors at the 2017 Annual Meeting.

While we do rely on ouran exemption, as a controlled company, from the Nasdaq Rules requirement that our Board be comprised of a majority of independent Directors, the Nasdaq Rules nevertheless require our Board to have an Audit Committee comprised of no fewer than three Directors, all of whom are independent. The Nasdaq Rules further require all members of the Audit Committee have the ability to read and fully understand financial statements and at least one member of the Audit Committee possess financial sophistication (i.e., qualify to be identified as a “Audit Committee Financial Expert” under Section 407 of the Sarbanes-Oxley Act of 2002). Messrs. Carlson, Eichten, Griffin and Riddiford each serve on the current Audit Committee, and the Board has determined each of the members of the current Audit Committee are independent under Nasdaq’sthe Nasdaq Rules and Messrs. Carlson and Riddiford each qualify as Audit Committee Financial Experts under Section 407 of the Sarbanes-Oxley Act of 2002. Messrs. Carlson, Eichten, and Griffin are standing for reelection to the Board and, if reelected, intend to serve as members of the Audit Committee for the comingone-year term.

We rely on ouran exemption, as a controlled company, from the Nasdaq Rules requirement that the compensation of our executive officers, including Dr. Vinciarelli, our Chief Executive Officer, be determined solely by independent Directors. However, all four members of the current Compensation Committee of the Board, Messrs. Carlson, Eichten, Griffin and Riddiford, are considered independent, and Messrs. Carlson, Eichten, and Griffin are standing for reelection to the Board and, if reelected, intend to serve as members of the Compensation Committee for the comingone-year term. The Compensation Committee is solely responsible for the administration of the Corporation’s stock option plans, with authority delegated by the Board to approve all recommended stock option awards.

We also rely on ouran exemption, as a controlled company, from the Nasdaq Rules requirement that the Board have a standing committee responsible for Director nominations and other governance matters. The Board

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believes it, as a whole, is in the best position to evaluate potential candidates for nomination as Director and, therefore, the full Board performs the function of such a committee.

Finally, while we rely on the exemptions from certain Nasdaq Rules requirements described above, we are not exempt from the requirement that independent Directors have regularly scheduled meetings at which only

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independent Directors are present. At each meeting of the Board, the independent Directors conduct such “executive sessions,” frequently with our outside counsel as an invited guest. In addition, at each meeting of the Audit Committee, which is comprised solely of the current four independent Directors, the independent Directors conduct private meetings with representatives of our independent registered public accounting firm, KPMG LLP (“KPMG”).

The Board and Its Committees

Our Board which currently consists of the 10 Nominees, has two standing committees: the Audit Committee and the Compensation Committee.

The Board held four threein-person meetings and acted by written consent in lieu of meetings on tenthree other occasions during 2015.2016. Each of the Directors attended 75% or more of the total number of meetings of the Board and meetings of the committees thereof on which each such Director serves. Directors are expected to attend each year’s Annual Meeting in person unless doing so is impracticable due to unavoidable conflicts. All of the Directors, except Mr. Carlson,Griffin, attended the 20152016 Annual Meeting of Stockholders.

Information regarding the functions performed by the Audit Committee is set forth in the section of this Proxy Statement entitled “Report of the Audit Committee.” The Audit Committee is governed by a written charter, approved by the Board on February 3, 2007, and reviewed each year. As stated above, the Board has determined all four members of the current Audit Committee are independent under the applicable Nasdaq Rules and Securities and Exchange Commission (“SEC”) regulations. TheMessrs. Carlson, Eichten, and Griffin are standing for reelection to the Board and, if reelected, intend to serve as members of the Audit Committee for the comingone-year term. As stated above, the Board also has determined that Messrs.Mr. Carlson and Riddiford meetmeets the definition of “Audit Committee Financial Expert” as defined by Item 407(d) of RegulationS-K. The Audit Committee charter is posted on the Corporation’s website, www.vicorpower.com, under the heading “About Vicor” and the subheading “Corporate Governance.” The Audit Committee held fivesix meetings during 2015.2016.

The Compensation Committee is responsible for approving, based on the recommendation of Dr. Vinciarelli, the compensation for the executive officers of the Corporation, approving all grants of stock options by the Corporation and its subsidiaries, and administering the Corporation’s stock option plans pursuant to authority delegated to it by the Board. The Compensation Committee is governed by a written charter, approved by the Board on October 18, 2013, and subject to review each year. The Compensation Committee held threefive meetings during 20152016 and acted by written consent in lieu of meeting on 2415 other occasions to approve stock option awards granted during 2015.2016. The Compensation Committee charter is posted on the Corporation’s website, www.vicorpower.com, under the heading “About Vicor” and the subheading “Corporate Governance”.

Board Leadership and Role in Risk Management

Given the Corporation’s status as a controlled company and Dr. Vinciarelli’s leadership of the Corporation since its founding, he fulfills both the roles of Chairman of the Board and Chief Executive Officer. As Chairman of the Board, Dr. Vinciarelli presides over meetings of the Board and, in collaboration with Mr. Simms, in his capacity as Corporate Secretary, establishes an agenda for each meeting. The Board does not have a lead independent Director. As Chief Executive Officer, Dr. Vinciarelli is responsible for setting the strategic direction of the Corporation, the leadership of the organization, and the operational and financial performance of the Corporation.

Under Dr. Vinciarelli’s leadership, the Board provides the highest level of direction and authority for the Corporation. The Board advises and oversees executive management, which, under Dr. Vinciarelli’s leadership, is responsible for theday-to-day operations of the Corporation’s affairs. The Board reviews, assesses, and directs our long-term strategic plans and provides oversight and guidance on all matters influencing the Corporation’s well-being.

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The Board has an active role, as a whole and also at the committee level, in overseeing identification, analysis, and management of the Corporation’s risks. The Board regularly reviews information regarding the Corporation’s strategy, operations, financial performance and position, and legal and regulatory affairs, addressing the risks associated with each. Messrs. Kelleher, Simms, and Tuozzolo, in their capacities as former President of the Brick Business Unit, Chief Financial Officer, and President of Picor Corporation, respectively, provide first-hand information and insight to the Board regarding all enterprise risks. Mr. Anderson, as the former Chief Executive Officer of an important supplier to the Corporation, provides valuable external perspectives on a range of challenges facing the Corporation, including evolving technology and intensifying competition. The independent Directors, given their breadth of experience and expertise, as well as their governance responsibilities as the sole members of the Audit Committee and the Compensation Committee, contribute to an ongoing assessment of the integrity of our financial reporting processes and systems and the appropriateness and effectiveness of our compensation programs.

While the Board is ultimately responsible for the Corporation’s risk management, the Audit Committee, comprised of independent Directors, plays a primary and important role in assisting the Board in overseeing such responsibilities, with particular focus, as mandated by the Sarbanes-Oxley Act of 2002, on the integrity and effectiveness of the Corporation’s financial reporting processes. The Audit Committee reviews our guidelines and policies on management of enterprise risks, including assessment and management of the Corporation’s major financial exposures and management’s monitoring and control of such exposures. At each meeting of the Audit Committee, members of management, led by Mr. Simms, in his capacity as Chief Financial Officer, present information addressing issues related to risk identification, analysis, and mitigation. Also at each meeting of the Audit Committee, the committee members meet privately with representatives of our independent auditors, KPMG.

In addition to the risk oversight role undertaken by the Audit Committee, the Compensation Committee assists the Board in overseeing the Corporation’s compensation policies and practices as they relate to the Corporation’s risk management and risk-taking incentives. The Compensation Committee has determined the compensation policies and practices for the Corporation’s employees are not reasonably likely to have a material adverse effect on the Corporation, as the incentives of the Corporation’s compensation programs are believed to be aligned with our strategic, operational, and financial goals and the interest of our Stockholders.

Upon learning from Mr. Riddiford of his intent to not stand for reelection to the Board, the Board concluded the Board’s effectiveness in overseeing the identification, analysis, and management of the Corporation’s risks will not materially change due to Mr. Riddiford’s retirement.

Director Nomination Process

As indicated above, the full Board performs the Director nomination function for the Corporation. The Board does not have a charter governing the Director nomination process, although it has established Director nomination procedures setting forth the process for identifying and evaluating Director nominees. The Corporation’sBy-Laws require that our Stockholders approve the number of Directors for the coming year at each Annual Meeting of Stockholders, although theBy-Laws also allow the Board to reduce the number of Directors in the event of a vacancy on the Board and to increase the number of Directors at any time by majority vote of the Directors then serving.

Board Membership Criteria— At a minimum, the Board must be satisfied each candidate for nomination has high personal and professional integrity, has demonstrated exceptional ability and judgment, and is expected, in the judgment of the Board, to be highly effective, in collaboration with the other nominees to the Board, in collectively serving the interests of the Corporation and our Stockholders. In addition to the minimum qualifications set forth above, the Board seeks to select for nomination persons possessing relevant industry or technical experience and, in order to comply with the Nasdaq Rules regarding independence of Audit Committee members is maintained, persons meeting the independence requirements of the Nasdaq Rules and SEC regulations.

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Identifying and Evaluating Nominees — The Board may solicit recommendations from any sources it deems appropriate. The Board will evaluate all candidates for nomination in the same manner, evaluating the qualifications of any recommended candidate and conducting inquiries it deems appropriate, without discrimination on the basis of race, religion, national origin, sexual orientation, disability, or any other basis. In

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identifying and evaluating candidates for nomination, the Board may consider, in addition to the minimum professional qualifications discussed above and other criteria for Board membership approved by the Board from time to time, all facts and circumstances it deems appropriate or advisable, including, among other things, the breadth of experience, geographic representation, and backgrounds of other nominees. Based on these considerations, the Board may nominate a candidate it believes will, together with the other nominees, best serve the interests of the Corporation and our Stockholders.

Stockholder Recommendations— The Board’s policy is to review and consider, in accordance with the procedures described above, any candidates for nomination recommended by Stockholders entitled to vote for the election of Directors. All Stockholder recommendations of candidates for nomination must be submitted to our Corporate Secretary, Mr. Simms, at the address of the Corporation set forth above.

All Stockholder recommendations for Director candidates must include the following information:

Any stockholder seeking to present a Director nomination at an annual meeting must comply with the notice procedures in ourBy-Laws as described herein under “Stockholder Proposals.”

Communications with the Board

If a Stockholder wishes to communicate with any Director or the Board as a whole, he or she may do so by addressing such communications to:[Name(s) of Director(s)/Board of Directors of Vicor Corporation], c/o James A. Simms, Corporate Secretary, Vicor Corporation, 25 Frontage Road, Andover, MA 01810. All correspondence should be sent via certified U.S. mail, return receipt requested. All correspondence received will be forwarded promptly to the addressee(s).

Code of Business Conduct

The Corporation has established and adopted a Code of Business Conduct. This Code of Business Conduct is posted on the Corporation’s website, www.vicorpower.com, under the heading “About Vicor” and the subheading “Corporate Governance”.

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Executive Officers

Executive officers of the Corporation (designated as our “corporate officers” in accordance with ourBy-Laws) are appointed annually by the Board and hold office until the first meeting of the Board following the next annual meeting of Stockholders and until their successors are elected and qualified, or until their earlier death, resignation, or removal. The following persons are the Corporation’s executive officers:

Patrizio Vinciarelli, Ph.D., 69,70, Chairman of the Board, President, and Chief Executive Officer. Dr. Vinciarelli’s background and experience is contained in the section of the Proxy Statement entitled “Information Regarding Nominees.”

Sean Crilly, 58,59, Corporate Vice President, Engineering, Power Systems since June 2015. From December 2012 to May 2015, Mr. Crilly served as Vice President, Engineering, VI Chip. From 2006 to 2012, Mr. Crilly held the position of Director of Sustaining Engineering, and, from 2000 to 2006, the position of Manager, Test Engineering. Previously, Mr. Crilly held the positions of Project Manager, from 1996 to 2000, and Senior Test Engineer, from 1993 to 1996. Prior to joining the Corporation in 1993, Mr. Crilly was Vice President of Applications Engineering at Intepro Systems, specializing in power electronics test equipment. Earlier, he was employed in engineering roles at Schaffner and Nixdorf Computer. Mr. Crilly received a B.Eng. in Electronics from the Limerick Institute of Technology, Limerick, Ireland.

Philip D. Davies, 56,57, Corporate Vice President, Global Sales and Marketing, since February 2011. Prior to joining the Corporation, Mr. Davies was employed by the Solid State Light Engine business unit of OSRAM Sylvania as Business Creation Team Leader from September 2010 to February 2011. From 2006 to 2010, Mr. Davies held the position of Vice President, Sales and Marketing, with NoblePeak Vision Corporation, a developer of night vision camera cores. From 1995 to 2006, Mr. Davies served in various positions with Analog Devices, Inc., a manufacturer of high-performance analog, mixed signal and digital signal processing integrated circuits, most recently as Director of World Wide Business Development. From 1987 to 1995, Mr. Davies served in a number of positions with Allegro MicroSystems, Inc., a manufacturer of high-performance power and Hall-effect sensor integrated circuits, most recently as Vice President, Engineering. Mr. Davies received a B.S.E.E. and a Masters degree in Power Electronics from the University of Glamorgan.

Nancy L. Grava,45,46, Corporate Vice President, Human Resources, since July 2015. From 2009 to June 2015, Ms. Grava held the position of Director, Human Resources. From 2002 to 2009, Ms. Grava held the position of Senior Manager, Compensation and Benefits and, from 1999 to 2002, the position of Manager, Compensation and Benefits. Previously, Ms. Grava held various other positions within Human Resources since joining the Corporation in 1993. Ms. Grava received a B.A. from the Massachusetts School of Liberal Arts and an M.B.A. from Bentley University.

Alex Gusinov, 52,53, Corporate Vice President, Engineering, Power Components since June 2015. From 2006 to 2015, Mr. Gusinov served as Vice President of Design Engineering for Picor Corporation. He joined Picor in 2004 as Director of IC Design. Prior to joining Picor, Mr. Gusinov was employed by SIPEX Corporation from 1996 to 2004, most recently as Vice President of Design Engineering, Power Management. From 1986 to 1996, he was employed by Analog Devices, Inc., developing integrated circuits for telecom, fiber optics, video, and related applications. Mr. Gusinov received a B.S.E.E. from Boston University and an M.S. in Engineering Management from Gordon Institute of Tufts University.

Joseph A. Jeffery, Jr., 65,66, Corporate Vice President and Chief Information Officer since September 2015. From 2009 to 2015, Mr. Jeffery served as Vice President, Applications Development. From 1999 to 2009, Mr. Jeffery held the position of Director of Manufacturing Systems. Prior to joining the Corporation, Mr. Jeffery was employed for 27 years byM/A-COM Technology Solutions, serving in a variety of technical and management positions in their microwave, millimeter wave semiconductor, and IC business units. Mr. Jeffery received an Associate’s degree (EEE) from the Wentworth Institute of Technology.

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Barry Kelleher, 67, Corporate Vice President and President of the Corporation’s Brick Business Unit. In April 2016, Mr. Kelleher announced his intention to retire as an employee of the Corporation, effective December 31, 2016. Mr. Kelleher will continue to be an employee of the Company until that date, providing a range of services associated with the transition of his operational responsibilities to Mr. McNamara. Mr. Kelleher’s background and experience is contained in the section of the Proxy Statement entitled “Information Regarding Nominees.”

Michael S. McNamara, 55,56, Corporate Vice President, General Manager, Operations, since June 2015. Mr. McNamara held the positions of Corporate Vice President, Quality and Technical Operations, from May 2011 to May 2015, Vice President, Quality and Technical Operation of the Corporation’s Brick Business Unit from 2008 to April 2011, Vice President, Quality of the Corporation’s Brick Business Unit from 2006 to 2008, Senior Director of Quality from 2001 to 2008, Manager of Quality, Data and Analysis from 1999 to 2001 and Senior Quality Engineer from 1995 to 1999. Prior to joining the Corporation in 1995, Mr. McNamara was employed by Alpha Industries Inc., the predecessor to Skyworks Solutions, Inc. Mr. McNamara received a B.S. in Industrial Technology from the University of Lowell.

Richard J. Nagel, Jr., 59,60, Corporate Vice President, Chief Accounting Officer, since May 2006. From December 2007 to April 2008, Mr. Nagel also held the position of Interim Chief Financial Officer. From 2005 to 2006, Mr. Nagel held the position of Senior Director, Corporate Controller, and, from 1996 to 2005, Director, Corporate Controller. Prior to joining the Corporation in 1996, Mr. Nagel was employed by Ernst & Young LLP, an international public accounting firm, serving in a variety of positions from 1982 to 1996, most recently as Senior Manager. Mr. Nagel received a B.A. from Amherst College and an M.B.A. from the University of Rochester.

James A. Simms, 56,57, Corporate Vice President, Chief Financial Officer, Treasurer, and Corporate Secretary. Mr. Simms’ background and experience is contained in the section of the Proxy Statement entitled “Information Regarding Nominees.”

Claudio Tuozzolo, 53,54, Corporate Vice President and President of Picor Corporation, a subsidiary of the Corporation. Mr. Tuozzolo’s background and experience is contained in the section of the Proxy Statement entitled “Information Regarding Nominees.”

PRINCIPAL AND MANAGEMENT STOCKHOLDERS

The following table sets forth the beneficial ownership of the Corporation’s Common Stock and Class B Common Stock held by (1) each person or entity known to the Corporation to be the beneficial owner of more than five percent of the outstanding shares of either class of the Corporation’s common stock, (2) each Director and Nominee, (3) each executive officer of the Corporation, and (4) all Directors and executive officers as a group, in each case based on representations of the Directors and executive officers as of March 31, 2016,2017, and a review of filings on Schedules 13D and 13G under the Exchange Act. Except as otherwise specified, the named beneficial owner has sole voting and investment power over the shares set forth opposite such beneficial owner’s name. The information in the table reflects shares outstanding of each of the two classes of common stock on March 31, 2016,2017, and does not, except as otherwise indicated below, take into account conversions after such date, if any, of shares of Class B Common Stock into Common Stock, which, if they were to occur, would increase the voting control of persons who retain shares of Class B Common Stock.

The percentages shown have been determined as of March 31, 2016,2017, in accordance with Rule13d-3 under the Exchange Act, and are based on a total of 38,795,54639,104,390 shares of common stock that were outstanding on such date, of which 27,037,32827,346,172 were shares of Common Stock, entitled to one vote per share, and 11,758,218 were shares of Class B Common Stock, entitled to 10 votes per share. Each share of Class B Common Stock is convertible into one share of Common Stock at any time upon the election of the holder thereof.

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Pursuant to the provisions of our certificate of incorporation, shares of Class B Common Stock are transferrable only under the limited circumstances set forth therein and generally must be converted into shares of Common Stock in order to be sold. Such conversion may be effected by the delivery of the certificate(s) representing shares of Class B Common Stock, accompanied by a written notice of the election by the record holder thereof to convert, to either Mr. Simms, in his capacity as Corporate Secretary, c/o Vicor Corporation, 25 Frontage Road, Andover, MA 01810, or to the then-current transfer agent for our Common Stock. Any transfer

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of shares of Class B Common Stock not permitted under the provisions of our certificate of incorporation will result in the automatic conversion of those shares of Class B Common Stock into an equal number of shares of Common Stock.

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COMPENSATION DISCUSSION AND ANALYSIS

Philosophy

The primary objective of the Corporation’s compensation programs is to attract, motivate, and retain highly qualified and productive employees using a combination of cash and equity based rewards intended to motivate and reward superior performance. Salaries and, in appropriate circumstances, cash bonuses encourage effective performance relative to current plans and objectives, while stock options may be utilized to attract new employees, reward outstanding performers, promote longer-term focus, and more closely align the interests of employees with those of Stockholders.

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2014Stockholder Advisory Vote on Executive Compensation

At the Corporation’s annual meeting of Stockholders held on June 20,in 2014, Stockholders approved, on an advisory basis, the compensation of our named executive officersNamed Executive Officers as disclosed in our proxy statement for that annual meeting (a “Say on Pay” vote). The Compensation Committee believes this affirmsaffirmed our Stockholders’ support of the Corporation’s approach to executive compensation and, therefore, did not change its approach during 2015.2016.

At the 2011 annual meeting of Stockholders, Stockholders cast an advisory vote on the frequency of future Say on Pay votes. The frequencyalternative receiving the highest number of votes was a frequency of every three years, and, in accordance with the outcome of that advisory vote, our Board decideddetermined to hold a Say on Pay advisory vote every three years. Accordingly, our Board will next hold a Say on Pay advisory vote at the 2017 Annual Meeting. Our Board has proposed that Stockholders vote for an advisory vote on executive compensation every three years, as described in Proposal Three herein.

Overview of Executive Compensation

Dr. Vinciarelli, with input from Ms. Grava, our Corporate Vice President, Human Resources, makes periodic recommendations to the Compensation Committee with respect to the compensation of executives and other employees in leadership positions. The Compensation Committee approves the annual salary of Dr. Vinciarelli.Vinciarelli and other Named Executive Officers.

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Potential elements of compensation for our executive officers include: a base salary, cash bonuses, stock option awards, subsidized participation in group health, disability, and life insurance, cash contributions to a 401(k)tax-qualified retirement saving plan sponsored by the Corporation, and certain perquisites. All employees, including our Named Executive Officers, areemployees-at-will and, as such, do not have employment contracts with the Corporation. In the future, the Board believes that the Vicor Corporation 2017 Employee Stock Purchase Plan, referred herein as the “ESPP” (described herein in Proposal Seven), will become an important part of the Corporation’s overall compensation program, as the ESPP is intended to improve the Corporation’s ability to attract, retain, and motivate eligible employees, and further align the interests of eligible employees with those of our Stockholders.

Each component of compensation is described in the following table:

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Stock Option Programs

As described above, discretionary awards of stock options for the purchase of shares of Vicor Corporation, VI Chip Corporation, and Picor Corporation are a component of our executive compensation.compensation for executives and employees considered by Dr. Vinciarelli to be important contributors to the Corporation’s success. The Compensation Committee approves all stock option grants. We generally award a limited number ofnon-qualified stock options to a new employee upon hiring. Depending upon the business unit into which the individual is hired, we award stock options for the purchase of shares of Vicor Corporation, VI Chip Corporation, or Picor Corporation. Certain new hires have been awarded stock options granted by all three entities. From time to time, existing employees will be rewarded for superior performance through the award of additional stock options. The Corporation does not have a policy regarding the composition or a program involvingfrequency of discretionary awards of stock options.options or other forms of equity-based compensation.

The Compensation Committee approves all stock option grants. We have no set formula for the discretionary award of options.

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During 2016, 2015, 2014, and 2013,2014, options for the purchase of the Corporation’s Common Stock were awarded under the Vicor Corporation Amended and Restated 2000 Stock Option and Incentive Plan (the “Vicor 2000 Plan”). The exercise price of stock options for the purchase of the Corporation’s Common Stock is set at the closing price of a share of the Corporation’s Common Stock onNASDAQ-GS on the effective date of the grant. TheseGenerally, these option grants vest pro rataevenly each quarter over five years and have a10-year term.

During 2016, 2015, 2014, and 2013,2014, options for the purchase of VI Chip Corporation (“VI Chip”) common stock were awarded under the VI Chip Corporation Amended 2007 Stock Option and Incentive Plan as amended (the “2007 VI Chip Plan”). TheseGenerally, these option grants vest pro rata over five years and have a10-year term. On August 27, 2010, VI Chip awarded, also under the 2007 VI Chip Plan, 10-year term options with vesting tied to the achievement of certain financial performance goals. No further awards of such performance-based options have been made. All awards were reviewed and approved by the VI Chip Board of Directors, comprised of Dr. Vinciarelli and Mr. Simms, and the Corporation’s Compensation Committee. VI Chip stock options are granted at a price not less than the fair value of a share of VI Chip common stock on the date of grant, aswith such fair value determined by the VI Chip Board of Directors and the Corporation’s Compensation Committee, consistent with the valuation procedural requirements of Section 409A of the Internal Revenue Code.

During 2016, 2015, 2014, and 2013,2014, options for the purchase of Picor Corporation (“Picor”) common stock were awarded under the Picor Corporation Amended and Restated 2001 Stock Option and Incentive Plan as amended (the “2001 Picor Plan”). TheseGenerally, these option grants vest pro rata over five years and have a10-year term. All option grants were reviewed and approved by the Picor Board of Directors, comprised of Dr. Vinciarelli, Mr. Tuozzolo, Mr. Simms, and Mr. Andrew Durette, and the Corporation’s Compensation Committee. Picor stock options are granted at a price not less than the fair value of a share of Picor common stock on the date of grant, aswith such fair value determined by the Picor Board of Directors and the Corporation’s Compensation Committee, consistent with the valuation procedural requirements of Section 409A of the Internal Revenue Code.

On May 17, 2013, the Corporation commenced an offer (the “Exchange Offer”) to its employees and Directors to voluntarily exchange outstanding options to purchase shares of the Corporation’s Common Stock granted before January 1, 2013, whether or not vested, on a one-for-one basis, for replacement options to purchase shares of Common Stock. Outstanding options eligible for exchange included options with time-based vesting provisions as well as options with performance-based vesting provisions tied to the achievement of certain financial performance goals by our Brick Business Unit. Options for the purchase of shares of common stock of the Corporation’s subsidiaries, VI Chip and Picor, were not eligible for exchange. With the exception of Dr. Vinciarelli, who held no options to purchase shares of our Common Stock, all of the Corporation’s executive officers and Directors participated in the Exchange Offer.

Because of a sustained and significant decline in the price of a share of our Common Stock through 2012 and into 2013, approximately 91% of outstanding options for the purchase of Common Stock, as of the date of the Exchange Offer, were out-of-the-money (i.e., the price at which an option could be exercised to purchase a

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share of Common Stock was above the then current market value of such a share). In assessing the rationale of and merits of the Exchange Offer, the Board concluded outstanding options were no longer effective as incentives to retain and motivate employees. In structuring the Exchange Offer, the Board considered the interests and objectives of employee option holders and non-employee Stockholders, concluding the benefit to employee option holders of receiving stock options with a presumably lower exercise price and longer exercise period likewise would benefit all Stockholders by ensuring valuable employees were retained and provided proper incentives through the five-year vesting term of the new options. The objective of the Corporation’s stock option programs has been, and continues to be, to link the personal interests of award recipients to those of Stockholders, and the Board concluded the Exchange Offer was an important component in achieving that objective.

The Exchange Offer expired on June 17, 2013, with 638 eligible employees and Directors participating, resulting in the grant of new options for the purchase of 1,531,077 shares of Common Stock, representing approximately 91% of options eligible for exchange under the Exchange Offer. The stock option award data for Named Executive Officers presented below in the table “Summary Compensation Table for Fiscal 2015” reflect the disproportionate impact of the Exchange Offer on 2013 compensation totals.

During the fourth quarter of 2014, the Corporation cancelled certain stock options previously awarded to Messrs. Davies, Kelleher, and Simms in 2013 and awarded to those executives new stock options representing an equivalent value, as calculated using the Black-Scholes option-pricing model. Subsequent to the 2013 awards, the Corporation determined those grants exceeded the limit on the number of stock options that may be granted to an individual in a year, according to the terms of the 2000 Plan. In connection with this action, recorded for financial reporting purposes as a modification of existing options, a total of 129,028 stock options awarded in 2013 (the “Original Grants”) were cancelled and a total of 150,355 new stock options were awarded (the “New Grants”) to each of the three executives, as follows:

In accordance with the authoritative guidance for share-based compensation under the Financial Accounting Standards Board’s Accounting Standards Codification Topic 718:Compensation — Stock Compensation, there was no incremental increase in fair value associated with the New Grants to Messrs. Davies, Kelleher, and Simms.

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SUMMARY COMPENSATION TABLE FOR FISCAL 20152016

During the fourth quarter of 2014, the Corporation cancelled certain stock options previously awarded to Messrs. Davies Kelleher, and Simms in 2013 and awarded to those executives new stock options representing an equivalent value, as calculated using the Black-Scholes option-pricing model. The Original Grants and the New Grants made to Messrs. Davis, Kelleher, and Simms are further described in the “Compensation Discussion and Analysis” section of this Proxy Statement under the heading “Stock Option Programs.” In accordance with the authoritative guidance for share-based compensation under the Financial Accounting Standards Board’s Accounting Standards Codification Topic 718: Compensation — Stock Compensation, there was no incremental increase in fair value associated with the New Grants to Messrs. Davies Kelleher, and Simms and therefore no value is included under “Option Awards” with respect to the New Grants in 2014.

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Stock Option Plan Information

The following table sets forth certain aggregated information for the Corporation as of December 31, 2015 (the end of the most recently completed fiscal year),2016 regarding equity securities underlying stock option awards made under the Vicor 2000 Plan, the 2007 VI Chip Plan, and the 2001 Picor Plan. All equity compensation plans of the Corporation have been approved by Stockholders.

Stock options issued under the Vicor 2000 Plan, the 2007 VI Chip Plan, and the 2001 Picor Plan carry a change in control provision that automatically accelerates vesting and makes unvested options fully exercisable upon a change of control, as defined in the applicable plan.

GRANTS OF PLAN-BASED AWARDS FOR FISCAL 20152016

The following table presents the Corporation’s grants of plan-based awards to Named Executive Officers during 2015.2016. All grants to Named Executive Officers during 20152016 were under the Vicor 2000 Plan as follows:

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OUTSTANDING EQUITY AWARDS AT FISCALYEAR-END 2015 2016

The following tables present the outstanding equity awards at December 31, 20152016 held by our Named Executive Officers under the Vicor 2000 Plan, the 2007 VI Chip Plan and the 2001 Picor Plan as follows:

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