UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 14A

(Rule14A-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  ☑                            Filed by a Party other than the Registrant  ☐

Check the appropriate box:

MKS INSTRUMENTS, INC.

2 Tech Drive, Suite 201

Andover, Massachusetts 01810

NOTICE OF 20182020 ANNUAL MEETING OF SHAREHOLDERS

TO BE HELD ON MAY 9, 201812, 2020

To our Shareholders:

The 20182020 Annual Meeting of Shareholders of MKS INSTRUMENTS, INC., a Massachusetts corporation, will be held on Wednesday,Tuesday, May 9, 201812, 2020 at 10:00 a.m., Eastern Time, at MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, Massachusetts 01810 for the following purposes:

The shareholders will also act on any other business as may properly come before the meeting.

Instead of mailing a paper copy of our proxy materials to all of our shareholders, this year we are providingWe provide access to our proxy materials over the Internet under the U.S. Securities and Exchange Commission’s “notice and access” rules. As a result, we are mailingmail to our shareholders a Notice of Internet Availability of Proxy Materials, which we refer to as the Notice. We are mailing the Notice instead of a paper copy of thison or about March 27, 2020, and it contains instructions on how to access the proxy statement and our Annual Report for the fiscal year ended December 31, 2017,2019, which we refer to as the 20172019 Annual Report. We are mailing the Notice on or about March 28, 2018, and it contains instructions on how to access the proxy materialsReport, over the Internet. The Notice also contains instructions on how each of our shareholders can receive a paper copy of our proxy materials, including this proxy statement, our 20172019 Annual Report, and a form of proxy card or voting instruction card. All shareholders who do not receive the Notice, including shareholders who have previously requested to receive paper copies of proxy materials, will receive a paper copy of the proxy materials by mail unless they have previously requested delivery of proxy materials electronically. We have chosen to employ this distribution process to conserve natural resources and reduce the costs of printing and distributing our proxy materials.

The Board of Directors has fixed the close of business on March 7, 20184, 2020 as the record date for the determination of shareholders entitled to notice of, and to vote at, the Annual Meeting and any adjournment or postponement thereof. Your vote is important no matter how many shares you own. Whether you expect to attend the meeting or not, please vote your shares by using the Internet as described in the instructions included onin your Notice, by calling the toll-free telephone number, or, if you received a paper copy of the proxy materials, by completing, signing, dating and returning your proxy card or voting instruction form.card. Your prompt response is necessary to ensure that your shares are represented at the meeting. You can change your vote and revoke your proxy any time before the polls close at the meeting by following the procedures described in the accompanying proxy statement.

If you would like to attend the Annual Meeting and your shares are held by a broker, bank or other nominee, you must bring to the Annual Meeting a letter from the nominee confirming your beneficial ownership of such shares. In order to vote your shares at the Annual Meeting, you must obtain from the nominee a proxy issued in your name. You must also bring a form of personal identification.

By Order of the Board of Directors,

RICHARD S. CHUTEKATHLEEN F. BURKE

Secretary

Andover, Massachusetts

March 28, 201827, 2020

TABLE OF CONTENTS

i

i

ii

MKS INSTRUMENTS, INC.

2 Tech Drive, Suite 201

Andover, Massachusetts 01810

PROXY STATEMENT

This proxy statement is furnished in connection with the solicitation of proxies by the Board of Directors of MKS Instruments, Inc., a Massachusetts corporation, for use at the 20182020 Annual Meeting of Shareholders to be held on May 9, 201812, 2020 at 10:00 a.m., Eastern Time, at MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, Massachusetts 01810, and at any adjournment or postponement thereof, which we refer to as the 2020 Annual Meeting. References in this proxy statement to “we,” “us,” the “Company” or “MKS” refer to MKS Instruments, Inc. and its consolidated subsidiaries.

All proxies will be voted in accordance with the applicable shareholder’s instructions. If no choice is specified in the proxy, the shares will be voted in favor of the matters set forth in the accompanying Notice of 20182020 Annual Meeting of Shareholders. Any proxy may be revoked by a shareholder at any time before its exercise by delivery of written revocation to the Secretary of MKS. Attendance at the 2020 Annual Meeting will not in itself be deemed to revoke a proxy unless the shareholder gives affirmative notice at the 2020 Annual Meeting that the shareholder intends to revoke the proxy and vote in person.

Instead of mailing a paper copy of our proxy materials to all of our shareholders, this year we are providingWe provide access to our proxy materials over the Internet under the “notice and access” rules of the U.S. Securities and Exchange Commission, which we refer to as the SEC. As a result, we are mailingmail to our shareholders a Notice of Internet Availability of Proxy Materials, which we refer to as the Notice. We are mailing the Notice instead of a paper copy of thison or about March 27, 2020, and it contains instructions on how to access the proxy statement and our Annual Report for the fiscal year ended December 31, 2017,2019, which we refer to as the 20172019 Annual Report. We are mailing the Notice on or about March 28, 2018, and it contains instructions on how to access those documentsReport, over the Internet. The Notice also contains instructions on how each of our shareholders can receive a paper copy of our proxy materials, including this proxy statement, our 20172019 Annual Report, and a form of proxy card or voting instruction card. All shareholders who do not receive the Notice, including shareholders who have previously requested to receive paper copies of proxy materials, will receive a paper copy of the proxy materials by mail unless they have previously requested delivery of proxy materials electronically.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF SHAREHOLDERS TO BE HELD ON MAY 9, 201812, 2020

This proxy statement and the 20172019 Annual Report to Shareholders are available for viewing, printing and downloading athttp://investor.mksinst.com/financial-information/annual-reports.

A COPY OF OUR ANNUAL REPORT ON FORM10-K FOR THE YEAR ENDED DECEMBER 31, 20172019 AS FILED WITH THE SEC, EXCLUDING EXHIBITS, WILL BE FURNISHED WITHOUT CHARGE TO ANY SHAREHOLDER UPON WRITTEN REQUEST TO: INVESTOR RELATIONS DEPARTMENT, MKS INSTRUMENTS, INC., 2 TECH DRIVE, SUITE 201, ANDOVER, MA 01810. EXHIBITS WILL BE PROVIDED UPON WRITTEN REQUEST AND PAYMENT OF AN APPROPRIATE PROCESSING FEE.

VOTING OF SECURITIES AND VOTES REQUIRED

At the close of business on March 7, 2018,4, 2020, the record date for the determination of shareholders entitled to notice of, and to vote at, the 2020 Annual Meeting, there were issued and outstanding and entitled to vote 54,488,75754,871,406 shares of our common stock, no par value per share, which we refer to as our Common Stock. Each outstanding share entitles the record holder to one vote on each matter submitted at the 2020 Annual Meeting.

In order to transact business at the 2020 Annual Meeting, we must have a quorum. Under our Amended and RestatedBy-Laws, the holders of a majority of the shares of Common Stock issued and outstanding and entitled to vote at the 2020 Annual Meeting shall constitute a quorum for the transaction of business at the 2020 Annual Meeting. Shares of Common Stock held by shareholders present in person or represented by proxy (including “brokernon-votes” and shares that abstain or do not vote with respect to a particular proposal to be voted upon) will be counted for purposes of determining whether a quorum exists at the 2020 Annual Meeting. If a quorum is not present, the meeting will be adjourned until a quorum is obtained.

The affirmative vote of the holders of a plurality of the votes cast on the matter is required for the election of directors (Proposal One); provided, however, any director nominee who receives a greater number of withhold votes than affirmative votes, which we refer to as a Majority Withhold Vote, in an uncontested election must offer to tender to the Board of Directors his or her resignation promptly following the certification of election results. The Board of Directors must accept or reject a resignation within 90 days following the certification of election results and publicly disclose its decision. Accordingly, the nominees who receive the highest number of votes of the shares present, in person or by proxy, and entitled to vote shall be elected to the available Class IIII Director positions, and in the event any nominee receives a Majority Withhold Vote, the resignation policy will apply as summarized here and as set forth in Section B.4 of our Corporate Governance Guidelines which are posted on our website atinvestor.mksinst.com in the Corporate Governance tab. The advisory vote on executive compensation (Proposal Two) and the ratification of PricewaterhouseCoopers LLP (Proposal Three) require the affirmative vote of the holders of a majority of the votes cast on the matter. Proposal Two is anon-binding proposal.

Shares held by shareholders who abstain from voting as to a particular matter, and “brokernon-votes,” which are shares held in “street name” by banks, brokers or nominees, who indicate on their proxies that they do not have discretionary authority to vote such shares as to a particularnon-routine matter, including the election of directors and the advisory vote on executive compensation, will not be counted as votes in favor of, or as votes cast for, a matter. Accordingly, abstentions and brokernon-votes will have no effect on the voting on a matter that requires the affirmative vote of a majority of the votes cast on the matter. If the shares you own are held in street name by a bank or brokerage firm, your bank or brokerage firm, as the record holder of your shares, is required to vote your shares according to your instructions. In order to vote your shares, you will need to follow the directions your bank or brokerage firm provides you.

PROPOSAL ONE – ELECTION OF DIRECTORS

Our Amended and RestatedBy-Laws provide for a Board of Directors that is divided into three classes. The term of the Class I Directors expires at the 20182021 Annual Meeting of Shareholders, the term of the Class II Directors expires at the 20192022 Annual Meeting of Shareholders and the term of the Class III Directors expires at the 2020 Annual Meeting. Our Board of Directors, upon the recommendation of our Nominating and Corporate Governance Committee, has nominated Gerald G. ColellaJoseph B. Donahue and Elizabeth A. MoraJanice K. Henry to serve as Class IIII Directors for a term to expire at the 20212023 Annual Meeting. Mr. Colella and Ms. Mora currently serve as directors.Meeting of Shareholders. Each nominee has consented to being named herein and, if elected, to serve as a director until his or her successor is duly elected and qualified.

Shares represented by all proxies received by the Board of Directors and not so marked as to withhold authority to vote for an individual director will be voted (unless one or more nominees are unable or unwilling to serve) for the election of the nominees named below. The Board of Directors expects that each of the nominees named below will be available for election, but if anyeither of them is not a candidate at the time the election occurs, it is intended that such proxies will be voted for the election of a substitute nominee to be designated by the Board of Directors.

THE BOARD OF DIRECTORS BELIEVES THAT APPROVAL OF THE ELECTION OF GERALD G. COLELLAJOSEPH B. DONAHUE AND ELIZABETH A. MORAJANICE K. HENRY TO SERVE AS CLASS IIII DIRECTORS IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” BOTH NOMINEES.

DIRECTORS

Set forth below are the names and ages of each member of our Board of Directors (including those who areand our two director nominees, for election as Class I Directors)Joseph B. Donahue and Janice K. Henry, the positions and offices held, principal occupation and business experience during at least the past five years, the names of other publicly held companies on which the individual currently serves, or in the past five years has served, as a director and the year each member of our Board of Directors joined our Board. We have also included information about each director’sindividual’s specific experience, qualifications, attributes, or skills that led the Board of Directors to conclude that he or she should serve as a director of MKS. Information with respect to the number of shares of Common Stock beneficially owned by each director,individual, directly or indirectly, as of January 1, 2018,2020, appears in this proxy statement under the heading “Security Ownership of Certain Beneficial Owners and Management.” Robert J. Phillippy,John R. Bertucci, Gregory R. Beecher and Rick D. Hess, who currently servesserve as a Class I Director, isIII Directors, are not standing forre-election to the Board of Directors and, accordingly, histheir tenure as a directordirectors will end as of the date of our 20182020 Annual Meeting on May 9, 2018.12, 2020. For this reason, their biographical information and qualifications have been omitted below.

Name		Year Became Director		Background and Qualifications
Gerald G. Colella		2014		Mr. ColellaDr. Lee has served as our President and Chief Executive Officer and President since January 2014.2020. From February 2013 until December 2013, Mr. ColellaSeptember 2019 to January 2020, he served as our President, from May 2018 to September 2019, he served as our President and Chief Operating Officer. HeOfficer, and he served as our Senior Vice President and Chief Operating Officer from November 2016 until May 2018. From January 20102014 until February 2013 andOctober 2016, Dr. Lee served as our Senior Vice President and Chiefof Business Officer from April 2005Units. From November 2012 until January 2010. In addition, Mr. Colella alsoDecember 2013, Dr. Lee served as our Acting GroupSenior Vice President, PRG Products,Controls, HPS (our integrated process solutions business), and Pressure, Flow, Measurement and Control, or PFMC. From January 2011 to November 2012, he served as Senior Vice President, Controls and PFMC, and from JulyOctober 2007 to March 2010. From October 1997 to April 2005,January 2011, he served as our Group Vice President, Global BusinessControls and Service Operations; from March 1996 to October 1997, he served as our Director of Materials Planning and Logistics; and from 1994 to 1996, he served as our Materials Planning and Logistics Manager. Mr. Colella joined MKS in 1983. He holds a B.A. in Secondary Education from the University of Massachusetts and an M.B.A. from Southern New Hampshire University. Mr. Colella’s 35 years of experience within the Company gives him particularly deep insight into our organization.
Peter R. Hanley		2008		From December 2009 until November 2010, Dr. Hanley served as an occasional consultant to Novellus Systems, Inc. (now Lam Research Corporation), a leading developer of semiconductor manufacturing equipment. From January 2004 until December 2007, Dr. Hanley served as a part-time employee of Novellus, engaged primarily in executive training. Dr. Hanley served as President of Novellus from May 2001 to December 2003. Prior to that, he served as Novellus’ Executive Vice President of Worldwide Sales from June 1992 until May 2001.Information Technology products. Prior to joining Novellus,MKS, Dr. HanleyLee served from 1985 to 1992as the Managing Director of Factory Technology and Projects within the Solar Business Group at Applied Materials, Inc., a global leader providing processing equipment to the semiconductor and display markets, most recentlyfrom February 2007 until October 2007. From 2002 until 2007, he served as Group Vice President of Worldwide Sales and Service and previously as Vice President and General Manager of their Etch Products Division. Before joiningthe Cleans Product Group and the Maydan Technology Center at Applied Materials. Prior to Applied Materials, Inc., Dr. HanleyLee served from 1978 to 19841997 until 2002 as Research Director of the Silicon Fabrication Research Department at Varian Associates,Lucent Technologies, Inc., a leadervoice, data and video communications provider, and from 1991 until 1997 as a Member of the Technical Staff in the semiconductor capital equipment industry, most recently as Vice President of Technology and previously as Vice President and General Manager of their Extrion Ion Implantation Division.Plasma Processing Research Group within Bell Labs. Dr. Hanley has servedLee serves as a member of the Advisory BoardDiversity Committee of Orbotech Ltd.The Charles Stark Draper Laboratory, Inc., a publicly held provider of yield-enhancingnon-profit engineering research and production solutions, since 2014.development laboratory serving the national interest in applied research, engineering development, advanced technical education, and technology transfer. Dr. HanleyLee holds a B.S. in Mechanical Engineering from NortheasternPrinceton University and both an M.S.C.E.P. and a Ph.D. from the Massachusetts Institute of Technology, all in Applied PhysicsChemical Engineering. Dr. Lee’s education combined with his technical understanding of our numerous and varied complex products, gained from Cornell University. Dr. Hanley’s substantial backgroundover twelve years of experience working in the semiconductor industry for almost 40 years, including senior managementprogressive leadership roles at Novellusour Company, and Applied Materials, twopreviously at one of MKS’our largest customers, provides the Board of Directorsprovide him with insights into the industry’s sales and marketing challenges and opportunities.

Name		Year Became Director		Background and Qualifications
Rick D. Hess		2017		Mr. Hess has served as Strategic Advisor to the Chief Executive Officer of Analog Devices, Inc., a publicly held semiconductor company, specializing in data conversion and signal processing technology, since June 2017. From 2014 to 2017, Mr. Hess served in various senior roles at Analog Devices, including Executive Vice President from September 2016 to June 2017; Senior Vice President, Communications and Automotive Business Group from November 2014 to September 2016; and Vice President, Radio and Microwave Group from July 2014 to November 2014. Before joining Analog Devices, Mr. Hess served as the Chief Executive Officer of Hittite Microwave Corporation from February 2013 to July 2014 (when it was acquired by Analog Devices). From 2011 to 2013, he was Vice President at American Superconductor Corporation, a provider of technologies and solutions for the electrical power infrastructure industry. From 2006 to 2010, Mr. Hess was President and Chief Executive Officer of Konarka Technologies, Inc., a developer of advanced photovoltaic cells on flexible plastic. From 2004 to 2006, he was President and Chief Executive Officer of Integrated Fuel Cell Technologies, Inc., a developer of fuel cell systems. From 1989 to 2004, Mr. Hess held several positions atM/A-COM, a semiconductor provider of high frequency components and systems for the wireless, defense, public safety and automotive markets, including President from 1999 to 2004. Mr. Hess had previously founded Stable Energy Sources, a manufacturer of microwave subsystems and components serving military and industrial markets. Mr. Hess served as a member of the Board of Directors of Hittite Microwave Corporation from 2005 until 2014. Mr. Hess received a B.S. in Electrical Engineering from Purdue University and an M.S. in Electrical Engineering from Johns Hopkins University. Mr. Hess’30-plus years in executiveunique leadership roles in the microwave, semiconductor, energy and manufacturing industries qualify him to serve as a member of our Board of Directors.perspective.
Jacqueline F. Moloney		2016		Ms. Moloney has served since 2015 as the Chancellor of the University of Massachusetts, Lowell, a public university with over 17,000 students, and served as its Executive Vice Chancellor from 2007 to 2015. Ms. Moloney has been a tenured professor at the University since 1994 and served as the Dean of Online and Continuing Education from 1994 to 2007. Since 2008, Ms. Moloney has served as a director and member of the audit,compensation, nominating and corporate governance, strategic planning, marketing, investment, technology and executive committees of Enterprise Bancorp, Inc., a publicly held bank. She holds an Ed.D. from the University of Massachusetts, Lowell. Ms. Moloney has over 30 years of experience as a leader innon-profit organizations. She has a deep history of working with business and industry, and she established the first incubators at the University of Massachusetts, Lowell, which are the home to approximately 50 early stage companies. She provides valuable knowledge and insight on emerging strategic planning and management and business trends.

Director Skills, Experience and Background

MKS is a global provider of instruments, systems, subsystems and process control solutions that measure, monitor, deliver, analyze, power and control critical parameters of advanced manufacturing processes to improve process performance and productivity for our customers. Many of the markets for our products are cyclical and highly competitive. As we discuss below under Corporate Governance – Director Candidates, the Nominating and Corporate Governance Committee is responsible for evaluating the appropriate skills, experience and background that MKS seeks in Board members in the context of our business and the existing composition of the Board. This evaluation includes numerous factors, such as integrity, business acumen, knowledge of our business and industry, effectiveness, experience, diligence, conflicts of interest and the ability to act in the interests of all shareholders.

Listed below are the skills and experience that we consider important for our directors given our current business and organizational structure. The continuing directors’ and director nominees’ biographies and the matrix below note each director’s and director nominee’s relevant experience, qualifications and skills relative to this list.

Skills/Competencies

AgreementsA significant portion of our sales are derived from products sold to semiconductor capital equipment manufacturers and semiconductor device manufacturers. In addition, our products are used in the industrial technologies, life and health sciences, as to Nomination

Mr. Bertucci resigned from his employment with MKS effective December 31, 2006. Mr. Bertucci’s employment agreement provided that if Mr. Bertucci resigned from his employment, then, subject to applicable law,well as research and defense markets. Directors who have education and experience in semiconductor technology and other industrial technologies are valuable for their perspectives on our Amendedresearch and RestatedBy-Laws,development efforts, competing technologies, the products and processes we develop, our Restated Articles of Organizationmanufacturing and assembly and the directors’ fiduciary duties,markets in which we compete.

Directors with a background in mergers and acquisitions, and business development provide insights into developing and implementing strategies for growing our business. Useful experience in this area includes skills in assessing and analyzing the “fit” of a proposed acquisition with our long-term strategy, valuing transactions and assessing management’s integration plans with existing operations.

Directors who have served in senior leadership positions are important to us because they have the experience and perspective to analyze, shape, and oversee the execution of important operational and policy issues.

Directors with public company board experience understand the dynamics and operation of a corporate board, the relationship of a public company board to the Chief Executive Officer and other executive officers, the legal and regulatory landscape in which public companies must operate, and how to oversee an ever-changing mix of strategic, operational, and compliance-related matters.

We are a global organization with manufacturing, research and development, and sales offices in many countries. We sell our products to thousands of customers worldwide and a significant portion of our revenues are from sales to customers in international markets. Our manufacturing facility locations include Austria, China, France, Germany, Israel, Italy, Mexico, Romania, Singapore, South Korea, the United Kingdom and the United States. Because of these factors, directors with international experience can provide valuable business, regulatory and cultural perspectives regarding many important aspects of our business.

Functional Background

Knowledge of financial markets, financing operations, and accounting and financial reporting processes is very important as it assists our directors in understanding, advising on, and overseeing our capital structure, financing and investing activities as well as our financial reporting and internal controls.

Our products incorporate sophisticated technologies to measure, monitor, deliver, analyze, power and control complex semiconductor and advanced manufacturing processes, thereby enhancing uptime, yield and throughput for our customers. We have developed, and continue to develop, new products to address industry trends. Directors with education and experience in engineering, and research and development provide valuable perspectives regarding our research and development efforts, competing technologies, the products and processes we develop, our manufacturing and assembly and the markets in which we compete.

Directors with a regulatory, legal or governance background can assist the Board in fulfilling its oversight responsibilities regarding our compliance, engagement with regulatory authorities, and governance structure.

Directors with marketing, brand management and sales experience can provide expertise and guidance as we seek to grow sales, expand the markets in which we compete, and strengthen our brands.

As we operate in many cyclical markets, with rapid demand changes, and have a broad footprint of international manufacturing operations, understanding of and experience with manufacturing and other operational processes are valuable assets to our Board.

The markets we serve increasingly rely on digitization and electronic connectivity as growth drivers, including, for example, the Internet of Things, or IoT. Further, we rely on various information technology networks and systems, some of which are managed by third parties, to process, transmit and store electronic information and to carry out and support a variety of business activities, and the safety and security of our digital information is paramount to our success. Directors shall nominate Mr. Bertucci for election aswho have a Class III directorsophisticated understanding of global digitization, and/or cybersecurity literacy can assist with the Board’s oversight of driving future growth and consider Mr. Bertucci for appointment as Chairmansecuring our digital information in the rapidly evolving digital landscape.

Personal Demographics

Representation of a mix of ages, gender and racially diverse perspectives expand the Board’s understanding of the needs and perspectives of our customers, suppliers, employees and stockholders. In addition, we consider the tenure each director has on our Board.

Board Skills Matrix

Listed below are the skills and competencies that we consider important for our directors and director nominees to ensure effective oversight of Directors, until such time as Mr. Bertucci is no longer eligiblethe Company’s business. The continuing directors’ and director nominees’ biographies note each continuing director’s and director nominee’s relevant experience, qualifications and skills relative to this list.

Current Members

Nominees

1

2

3

4

5

6

7

8

9

1

2

SKILLS/COMPETENCIES

•  Industry Experience

✓

✓

✓

✓

✓

✓

✓

✓

✓

•  M&A Business Development Experience

✓

✓

✓

✓

✓

✓

✓

✓

✓

•  CEO/COO/CFO Experience

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

•  Experienced Director

✓

✓

✓

✓

✓

✓

✓

•  International Experience

✓

✓

✓

✓

✓

✓

✓

✓

✓

FUNCTIONAL BACKGROUND

•  Accounting/Finance

✓

✓

✓

•  Engineering/R&D

✓

✓

✓

✓

✓

•  Regulatory/Legal/Governance

✓

✓

✓

•  Marketing/Sales

✓

✓

✓

•  Operations

✓

✓

✓

✓

✓

•  Digitization/Cybersecurity/IoT

✓

✓

✓

PERSONAL DEMOGRAPHICS

•  Tenure (years)

50

2

14

6

3

4

8

1

0

0

0

•  Age

79

52

62

63

66

66

59

53

57

68

61

•  Gender (Female/Male/Nonbinary)

M

M

M

M

M

F

F

F

M

F

M

•  Racial Diversity(Caucasian/Non-Caucasian)

C

N

C

C

C

C

C

C

N

C

C

Demographic Ratio Graphs

The following demographic ratio graphs show data for nomination as a director.

PROPOSAL TWO – ADVISORY VOTE ON EXECUTIVE COMPENSATION

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, or the Dodd-Frank Act, which added Section 14A to the Exchange Act, enables our shareholders to vote to approve, on anon-binding, advisory basis, the compensation of our 2019 Named Executive Officers as disclosed in this proxy statement under the heading “Executive Compensation” including “Compensation Discussion and Analysis,” the tabular disclosure regarding such compensation, and the accompanying narrative disclosure. This vote is not intended to address any specific item of compensation, but rather the overall compensation of our 2019 Named Executive Officers and the philosophy, policies and practices of executive compensation described in this proxy statement. The advisory vote is not a vote on our compensation practices fornon-executive employees or our Board of Directors. The Dodd-Frank Act requires the Company to hold the advisory vote on executive compensation at least once every three years, but we have elected to submit the advisory vote to shareholders annually.

As described in detail under the heading “Executive Compensation — Compensation Discussion and Analysis,” our executive compensation programs are designed to attract, motivate, and retain our Named Executive Officers,executive officers, who are critical to our success. Under these programs, our Named Executive Officersexecutive officers are rewarded for the achievement of specific short-term and long-term goals. Please see the “Compensation Discussion and Analysis” for additional details about our executive compensation philosophy and programs, including information about the compensation of our 2019 Named Executive Officers for the 2017 fiscal year.Officers.

The Compensation Committee continually reviews the compensation programs for our Named Executive Officersexecutive officers to ensure they achieve the desired goals of aligning our executive compensation structure with our shareholders’ interests and current market practices.

Our Board of Directors is asking shareholders to approve anon-binding advisory vote on the following resolution:

RESOLVED, that the compensation paid to the Company’s 2019 Named Executive Officers, as disclosed pursuant to the compensation disclosure rules of the SEC, including the Compensation Discussion and Analysis, the compensation tables and any related material disclosed in this proxy statement, is hereby approved.

This vote on the compensation of our 2019 Named Executive Officers is advisory, and therefore not binding on the Company, the Compensation Committee or our Board of Directors. Our Board of Directors and our Compensation Committee value the opinions of our shareholders and to the extent there is any significant vote against the 2019 Named Executive Officers’ compensation as disclosed in this proxy statement, we will consider our shareholders’ concerns and the Compensation Committee will evaluate whether any actions are necessary to address those concerns.

THE BOARD OF DIRECTORS BELIEVES THAT THE PROPOSAL TO APPROVE, ON ANON-BINDING ADVISORY BASIS, THE EXECUTIVE COMPENSATION CONTAINED IN THIS PROXY STATEMENT IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” THIS PROPOSAL.

PROPOSAL THREE – RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC

ACCOUNTING FIRM

Our Audit Committee has selected PricewaterhouseCoopers LLP, or PwC, as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2018.2020. PwC was our independent registered public accounting firm for the fiscal year ended December 31, 2017.2019.

Representatives of PwC are expected to be present at the 2020 Annual Meeting and will have the opportunity to make a statement if they so desire and will be available to respond to appropriate questions from shareholders. In the event that the ratification of the selection of PwC as our independent registered public accounting firm is not obtained at the 2020 Annual Meeting, the Board of Directors will reconsider its appointment.

THE BOARD OF DIRECTORS BELIEVES THAT THE PROPOSAL TO RATIFY THE SELECTION OF PWC AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE FISCAL YEAR ENDING DECEMBER 31, 20182020 IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” THIS PROPOSAL.

CORPORATE GOVERNANCE

Board Independence

The Board of Directors has determined that all of the members of the Board of Directors, other than Mr. Colella and Mr. Phillippy,Dr. Lee, are independent as defined under the rules of the Nasdaq Stock Market, or Nasdaq.

Board Leadership Structure

Since 2005, we have separated the roles of Chief Executive Officer and Chairman of the Board of Directors in recognition of the differences between the two roles. The Chief Executive Officer is responsible for setting the strategic direction of the Company and theday-to-day leadership and performance of the Company, while the Chairman of the Board of Directors provides guidance to the Chief Executive Officer, sets the agenda for Board meetings and presides over meetings of the full Board of Directors. Mr. Bertucci, who has been our Chairman of the Board of Directors since 1995, will not be standing forre-election to the Board and, accordingly, his tenure as a director and Chairman will end as of the date of our 2020 Annual Meeting on May 12, 2020. Mr. Colella, our former Chief Executive Officer and current member of our Board of Directors, will assume the role as Chairman at that time.

In addition, the Board of Directors has established the position of Lead Director. Our Corporate Governance Guidelines provide that during any period in which the Chairman of the Board of Directors is not an independent director, and in such other instances as the Board of Directors may determine from time to time, a Lead Director shall be elected by and from the independent directors. While we are not currently obligated under our Corporate Governance Guidelines to have a Lead Director, as our Chairman of the Board of Directors is independent, we will be required to have currently elected to continue to do so.a Lead Director in May 2020 when Mr. Colella, our former Chief Executive Officer and anon-independent member of our Board of Directors, assumes the role of Chairman. Mr. Beecher, who has served asbeen our Lead Director since 2012.2012, will not be standing forre-election to the Board and, accordingly, his tenure as a director and Lead Director will end as of the date of our 2020 Annual Meeting on May 12, 2020. The Board will appoint a new Lead Director at that time.

The primary role of the Lead Director is to serve as a liaison between the independent directors and the Chairman of the Board of Directors and/or the Chief Executive Officer and to represent the interests of the independent directors, as appropriate. Pursuant to our Corporate Governance Guidelines, which are posted on our website atinvestor.mksinst.com in the Corporate Governance tab, the Lead Director shall, among other matters:

Company’s policies with respect to financial risk assessment and financial risk management. Management regularly reports to the Audit Committee on these areas. The Compensation Committee assists the Board of Directors in fulfilling its oversight responsibilities with respect to the management of risks arising from our compensation policies and programs as well as succession planning as it relates to our Chief Executive Officer.planning. The Nominating and Corporate Governance Committee assists the Board of Directors in fulfilling its oversight responsibilities with respect to the management of risks associated with board organization, membership and structure, succession planning for our directors, corporate governance and corporate governance.social responsibility. In addition, from time to time, the Board of Directors may

constitute a special committee to focus on a particular matter or risk. When any of the committees receives a report related to material risk oversight, the chair of the relevant committee reports on the discussion to the full Board of Directors.

Transactions with Related Persons

Our code of business conduct and ethics sets forth the general principle that our directors, officers and employees should refrain from engaging in any activity having a personal interest that presents a conflict of interest. The code of business conduct and ethics prohibits certain specified activities, and also prohibits directors, officers and employees from engaging in any other activity that may reasonably be expected to give rise to a conflict of interest or to adversely affect our interests. The code of business conduct and ethics provides that all employees are responsible to disclose to their managers, the Chief Financial OfficerHuman Resources Department or the Legal Department any material transaction or relationship that reasonably could be expected to give rise to a material conflict of interest, and officers and directors must report such transactions to the Board of Directors, which shall be responsible for determining whether such transaction or relationship constitutes a material conflict of interest.

In addition, our written Related Person Transaction Procedures set forth the procedures for reviewing transactions that could be deemed to be “related person transactions” (defined as transactions required to be disclosed pursuant to Item 404 of RegulationS-K of applicable SEC regulations). In accordance with these procedures, directors and executive officers are required to submit annual certifications regarding interests and affiliations held by them and certain of their family members. We then review our records to determine whether we have engaged in any transactions since the beginning of our prior fiscal year with such affiliated persons and entities or with any person or entity known by MKS to be the beneficial owner of more than 5% of our voting securities, and provide a summary to the Audit Committee of any such material transaction in which the related person has a direct or indirect interest. In accordance with the procedures, the Audit Committee reviews any such transactions (including, but not limited to, transactions constituting related person transactions). In reviewing any such transaction, the Audit Committee considers, among other things, the related person’s interest in the transaction, the approximate dollar value of the transaction, whether the transaction was undertaken in the ordinary course of business, whether the terms of the transaction were at arm’s length, the purpose and potential benefits to the Company of the transaction, and whether the transaction is in the best interests of the Company. The Audit Committee may, in its sole discretion, impose such conditions as it deems appropriate in connection with any related person transaction. In accordance with the Audit Committee charter, the Audit Committee reviews the Related Person Transaction Procedures from time to time.

Wellington Management Group, LLP, Wellington Group Holdings LLP, Wellington Investment Advisors Holdings LLP, and Wellington Management Company LLP, which we refer to collectively as the Wellington Group, collectively beneficially owned approximately 5%7% of the Company’s outstanding voting shares as of December 31, 2017,2019, according to filingsa filing they have made with the SEC. Wellington Management LLC,LLP, an affiliate of the Wellington Group, manages cash accounts of MKS, in the aggregate amount of approximately $242$164 million as of December 31, 2017.2019. In 2017,2019, MKS paid Wellington Management LLCLLP approximately $246,000$300,000 for these cash management services. Wellington Management LLCLLP must manage the MKS cash accounts in accordance with, and subject to, the Company’s Corporate Investment Policy, which establishes clear guidelines for acceptable investments. As part of our Related Person Transaction Procedures, our Audit Committee reviewed the foregoing relationship with Wellington Management LLC.LLP.

Board of Director Meetings and Committees of the Board of Directors

The Board of Directors held four meetings in 2017.2019. During 2017,2019, each director attended at least 75% of the aggregate of the total number of meetings of the Board of Directors and the total number of meetings of all committees of the Board of Directors on which he or she served. Pursuant to our Corporate Governance Guidelines, directors are encouraged to attend our Annual Meetingannual meeting of Shareholders.shareholders. All of the directors then serving on the Board of Directors, other than Messrs. Chute and Hanley, who were not standing forre-election at the 2019 Annual Meeting, attended the 20172019 Annual Meeting of Shareholders.

The Board of Directors has established three standing committees — Audit, Compensation, and Nominating and Corporate Governance — each of which operates under a charter that has been approved by the Board of Directors. Each committee’s current charter is posted on our website atinvestor.mksinst.com in the Corporate Governance tab.

Audit Committee

The Audit Committee consists of Mr. Beecher (Chair), Ms. Moloney and Ms. Mora. The Board of Directors has determined that each of the three current members of the Audit Committee is an “audit committee financial expert” as defined in applicable SEC regulations. Each member of the Audit Committee also meets the requirements for independence under applicable Nasdaq and SEC rules. The Audit Committee’s responsibilities include:

The Audit Committee held five meetings in 2017.2019.

Compensation Committee

The Compensation Committee consists of Ms. Mora (Chair), Dr. HanleyMr. Batra and Mr. Hess. Dr. Peter R. Hanley also served on the Compensation Committee until May 2019 when his tenure as a director ended. Each member of the Compensation Committee meets the requirements for independence under applicable Nasdaq and SEC rules. The Compensation Committee’s responsibilities include:

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee consists of Ms. Moloney (Chair), Mr. Chute (Chair),Batra and Ms. Warner. Mr. Batra and Ms. Warner replaced Dr. Hanley and Ms. Moloney.Richard S. Chute, each of whom stepped down in May 2019 when his tenure as a director ended. Each member of the Nominating and Corporate Governance Committee meets the requirements for independence under applicable Nasdaq and SEC rules. The Nominating and Corporate Governance Committee’s responsibilities include:

interest and the ability to act in the interests of all shareholders. The Nominating and Corporate Governance Committee does not assign specific weights to particular criteria and no particular criterion is a prerequisite for each prospective nominee. The Nominating and Corporate Governance Committee also assesses the candidate’s professional background and skills against those of the existing Board members to ensure a breadth and diversity of expertise that suits the Company’s current and future business risks, industries and challenges. See “Directors — Board Skills Matrix.” Nominees shall not be discriminated against on the basis of race, religion, national origin, sex, sexual orientation, disability or any other basis proscribed by law. In considering director candidates, the Nominating and Corporate Governance Committee takes into account the value of diversity on the Board of Directors. While the Nominating and Corporate Governance Committee does not have a formal policy with respect to diversity, the Board of Directors and the Nominating and Corporate Governance Committee believe that it is essential that the members of the Board of Directors represent diverse viewpoints. In considering candidates for the Board of Directors, the Nominating and Corporate Governance Committee considers the entirety of each candidate’s credentials in the context of these standards. We believe that the backgrounds and qualifications of our directors, considered as a group, should provide a composite mix of experience, knowledge and abilities that will allow the Board of Directors to fulfill its responsibilities.

Shareholders may recommend individuals to the Nominating and Corporate Governance Committee for consideration as potential director candidates by submitting their names, together with appropriate biographical information and background materials and a statement as to whether the shareholder or group of shareholders making the recommendation has beneficially owned at least $2,000 in market value or 1% of our Common Stock, whichever is less, for at least a year as of the date such recommendation is made, to the Nominating and Corporate Governance Committee, in care of Kathleen F. Burke, Esq., Senior Vice President, and General Counsel and Secretary, MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, MA 01810. Assuming that appropriate biographical and background material has been provided on a timely basis, the Nominating and Corporate Governance Committee will evaluate shareholder-recommended candidates by following substantially the same process, and applying the same criteria, as it does in considering other candidates.

Shareholders also have the right under our Amended and RestatedBy-Laws to directly nominate director candidates, without any action or recommendation on the part of the Nominating and Corporate Governance Committee or the Board of Directors, by following the procedures set forth under the heading “Deadline for Submission of Shareholder Proposals for the 20192021 Annual Meeting” below.

DIRECTOR COMPENSATION

Cash Compensation

The following table summarizes the cash compensation payable by us tonon-employee directors with respect to the period from January 1, 2017 through December 31, 2017:in 2019:

In October 2017,February 2020, the Board of Directors, upon the recommendation of the Compensation Committee, approved several changes to theournon-employee director cash compensation program. The fees described inCompensation Committee recommended these changes after reviewing a competitive analysis of director compensation programs of our peer group prepared by the table above will remain in effect through March 31, 2018,Committee’s independent compensation consultant, Pearl Meyer, and finding that certain components of board compensation fell below the median of our peer group. The table below sets forth the cash compensation payable by ustonon-employee directors directors under the new cash compensation program effective as of AprilJanuary 1, 2018:2020:

In addition, from time to time, the Board of Directors may establish special committees related to specific matters and may include a retainer for service on such special committees in its discretion.

Equity Compensation

Non-employee directors are eligible for awards under our 2014 Stock Incentive Plan, which is administered by the Compensation Committee. In 2017,2019, under our director compensation program,non-employee directors received automatic grants of restricted stock units, or RSUs, on the date of the 20172019 Annual Meeting of Shareholders, with a grant date value of $160,000,$170,000, which RSUs shall vest in full on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after

the date of grant, on the 13 month anniversary of the date of grant).2020 Annual Meeting. In October 2017,February 2020, the Board of Directors, upon the recommendation of the Compensation Committee, increased the value of the annual RSU grant to $170,000$200,000 foreachnon-employee director, director, effective on the date of the 20182020 Annual MeetingMeeting. Our Compensation Committee recommended this increase after reviewing the board compensation analysis discussed above under Director Compensation — Cash Compensation and finding that the equity compensation paid tonon-employee members of Shareholders.our Board fell below the median of our peer group.

If a newnon-employee director joins our Board of Directors after our annual meeting of shareholders but before January 1^st1st of the following year, he or she will be entitled to an initial RSU grant with a value equal to the annual RSU grant. In the event anon-employee director joins our Board of Directors during the period from January 1st through the date of that year’s annual meeting of shareholders, he or she will not be entitled to an initial RSU grant but will be entitled to the annual RSU grant on the date of the annual meeting of shareholders.

Mr. Bertucci

Mr. Bertucci resigned from his employment as our Executive Chairman effective December 31, 2006. At that time, he remained a Class III directorDirector and becamenon-executive Chairman of the Board of Directors. Pursuant to the terms of his employment agreement, Mr. Bertucci receives retiree medical benefits for life for himself and his spouse, which had a net present value of $304,917$326,082 as of December 31, 2017. The agreement requires that he make an annual contribution towards the retiree benefits of $1,500.2019. Mr. Bertucci also receives a car allowance for life, which had a net present value of $191,952$169,444 as of December 31, 2017.2019. Mr. Bertucci receives no other retirement benefits.

The following table summarizes compensation paid tonon-employee directors in 2017.2019. Mr. Colella is excluded from the table because he iswas an executive officer in 2019, and his compensation is set forth in the Executive Compensation section below, under the heading “Executive Compensation Tables — Summary Compensation Table for 2017.2019.”

Director Compensation Table for 20172019

(4)(3)

In connection with his retirement and pursuant to the terms of his previous employment agreement, Mr. Bertucci receives retiree medical benefits and a car allowance. The retiree medical benefits consist of benefits for life for himself and his spouse, towards which Mr. Bertucci makes an annual contribution of $1,500.spouse. We paid $14,774$21,937 for this benefit in 2017.2019. We paid $14,898$19,864 for Mr. Bertucci’s car allowance in 2017.2019.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

Section 16(a) of the Securities Exchange Act of 1934, as amended, requires executive officers, directors and shareholders who beneficially own more than 10% of our Common Stock to file initial reports of ownership on Form 3 and reports of changes in ownership on Form 4 with the SEC and any national securities exchange on which our securities are registered. Executive officers, directors and greater than 10% beneficial owners are required by the SEC’s regulations to furnish us with copies of all Section 16(a) forms they file.

Based solely on a review of the copies of such forms, and amendments thereto, furnished to us and written representations from the executive officers and directors, pursuant to Item 405 of RegulationS-K, we believe that all of our executive officers, directors and greater than 10% shareholders have complied with all applicable Section 16(a) filing requirements.

AUDIT AND FINANCIAL ACCOUNTING OVERSIGHT

Audit Committee Report

The Audit Committee of our Board of Directors has reviewed our audited financial statements for the year ended December 31, 20172019 and discussed them with our management.

The Audit Committee has also received from, and discussed with, PricewaterhouseCoopers LLP, or PwC, our independent registered public accounting firm, various communications that our registered public accounting firm is required to provide to the Audit Committee, including the matters required to be discussed bybythe applicable requirements of the Auditing Standard No. 16,Public Company Accounting Oversight Board and the CommissionCommunications with Audit Committee..

The Audit Committee has received the written disclosures and the letter from our independent registered public accounting firm required by Independence Standards Board Standard No. 1 (Independence Standards Board Standard No. 1,Independence Discussions with Audit Committees), as adopted bythe applicable requirements of the Public Company Accounting Oversight Board in Rule 3600T,and the Commission, and has discussed with our registered public accounting firm theirits independence.

Based on the review and discussions referred to above, the Audit Committee recommended to our Board of Directors that the audited financial statements be included in our Annual Report on Form10-K for the year ended December 31, 2017.2019.

Respectfully submitted,

Gregory R. Beecher, Chair

Jacqueline F. Moloney

Elizabeth A. Mora

Principal Accountant Fees and Services

For the years ended December 31, 20172019 and 2016,2018, aggregate fees for professional services rendered by our independent registered public accounting firm, PwC, in the following categories were as follows:

Audit Fees

Audit fees billed for both years consisted of fees for professional services rendered for: (i) the audit of our annual consolidated financial statements, (ii) statutory audits, (iii) the review of our consolidated financial statements included in our quarterly reports on Form10-Q, (iv) audit services related to other reports filed with the SEC, and (v) the audit of our internal controls over financial reporting as required by the rules and regulations promulgated under Section 404 of the Sarbanes-Oxley Act of 2002.

Audit-Related Fees

Audit-relatedAudit-Related fees for the year ended December 31, 20172018 were for due diligence performed in connection with our acquisition of Electro Scientific Industries, Inc. and for professional services associated with a new revenue recognitionleasing accounting standard. Audit-related fees for the year ended December 31, 2016 were for due diligence services performed in connection with our acquisition of Newport Corporation in April 2016.

Tax Fees

Tax Fees for the yearyears ended December 31, 20172019 and December 31, 2018 were for services related to tax compliance, including the preparation of tax returns, and tax planning and tax advice, including assistance with foreign operations and foreign tax audits. Tax Fees for the year ended December 31, 2016 were for services related to tax planning and tax advice, including assistance with foreign operations and foreign tax audits, and for services related to our acquisition of Newport Corporation.

All Other Fees

All Other Fees for the years ended December 31, 20172019 and 20162018 were for accounting research software.

In 20172019 and 2016,2018, all Audit Fees, Audit-Related Fees, Tax Fees and All Other Fees werepre-approved pursuant to the Audit Committee’spre-approval requirements, described below.

Pre-Approval Policy and Procedures

The Audit Committee’s charter sets forth the Audit Committee’s obligations relating to the approval of all audit andnon-audit services that are to be performed by our independent registered public accounting firm. The

charter provides that we will not engage our independent registered public accounting firm to provide audit ornon-audit services unless the service ispre-approved by the Audit Committee. In addition, we will not engage any other accounting firm to provide audit services unless such services arepre-approved by the Audit Committee. It is the Audit Committee’s policy that with respect to services performed or to be performed by PwC in connection with each fiscal year of the Company, the annual fees fornon-audit services in such year shall not exceed one half of the aggregate fees payable to PwC for such year, without the prior express approval of the Audit Committee.

In connection with the foregoing, the Audit Committee may approve specific services in advance. In addition, from time to time, the Audit Committee maypre-approve specified types of services that are expected to be provided to us by our independent registered public accounting firm during the next 12 months. Any suchpre-approval of types of services is detailed as to the particular service or type of service to be provided and is also generally subject to a maximum dollar amount.

The Audit Committee has also delegated to the Chair of the Audit Committee the authority to approve any audit ornon-audit services to be provided to us by our independent registered public accounting firm. Any approval of services by the Chair of the Audit Committee pursuant to this delegated authority is reported on at the next meeting of the Audit Committee.

The Audit Committee has considered and determined that the provision of thenon-audit services noted in the foregoing table is compatible with maintaining PwC’s independence.

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL

OWNERS AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our Common Stock by (i) each shareholder known to us to be the beneficial owner of more than 5% of the outstanding shares of our Common Stock; (ii) the Named Executive Officers named in the Summary Compensation Table below; (iii) each of our current directors;directors and director nominees; and (iv) all of our directors, director nominees and executive officers as a group. Unless otherwise indicated in the footnotes to the table, all equity amounts set forth in the table are as of January 1, 2018;2020; and the address for each of our directors and executive officers is: c/o MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, Massachusetts 01810.

54,628,370 shares of Common Stock outstanding as of January 1, 2018.2020. Shares of Common Stock which an individual or entity has a right to acquire within the60-day period following January 1, 2018,2020, pursuant to the vesting of RSUs or the exercise of any stock options or other right, are deemed to be outstanding for the purpose of computing the percentage ownership of such individual or entity, but are not deemed to be outstanding for the purpose of computing the percentage ownership of any other person or entity shown in the table.

2020.

To our knowledge, there are no voting trusts or similar arrangements among any of the foregoing persons or entities with respect to the voting of shares of Common Stock.

EXECUTIVE OFFICERS

The following is a brief summary of the background of each of our current executive officers, other than Mr. Colella,Dr. Lee, whose background is described under the heading “Directors” above:

Name		Age		Background and Qualifications
				Business Segment Leader, Electronic Components and Electronic Article Surveillance, at Allied Signal, Inc., a diversified manufacturer, which merged with Honeywell, Inc. in 1999. Prior to joining Allied Signal, from May 1985 to June 1996, Mr. Werth held various management positions of increasing responsibility at Amoco Corporation, most recently serving as Vice President of Marketing and Business Development of that company’s ATx Telecom Systems, Inc. subsidiary (formerly Amoco Laser Company, which Mr. Werthco-founded in 1987 and which was sold to Scientific Atlanta in June 1996). Mr. WerthSchreiner holds a B.S. in Electrical Engineering from Montana State University, Bozeman as well as an Executive MBA from the University of Illinois, an M.S. in Engineering from Ohio State University and an M.B.A. from Eastern Michigan University.Colorado, Denver.

Our executive officers are appointed by the Board of Directors on an annual basis and serve until their successors are duly appointed and qualified. There are no family relationships among any of our executive officers or directors.

EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

Introduction

The purpose of this section of our proxy statement is to provide an overview of our executive compensation program, our compensation philosophy and objectives, and the material decisions we made with respect to each element of our executive compensation program.

In May 2019, we announced our Chief Executive Officer succession plan. Pursuant to that plan, on January 1, 2020, our then Chief Executive Officer, Gerald G. Colella, retired and our then President, John T.C. Lee, succeeded Mr. Colella as Chief Executive Officer and continued to serve as President. Mr. Colella continues to serve on our Board of Directors and, as previously announced, will assume the role of Chairman of our Board in May 2020.

Throughout this proxy statement, we refer to the following “Named“2019 Named Executive Officers”: listed below.

Following this Compensation Discussion and Analysis, you will find a series of tables containing specific information about the compensation earned or paid in 20172019 to our 2019 Named Executive Officers. When we announced Mr. Abrams’ retirement in May of 2018, we entered into a Transition and Retirement Agreement with Mr. Abrams, which set forth, among other things, Mr. Abrams’ compensation upon his retirement. As a result, we did not make any compensation decisions with respect to Mr. Abrams during 2019 and he was not eligible for a salary adjustment or a 2019 cash bonus, and he did not receive any equity awards. For this reason, Mr. Abrams is not included in the discussion that follows. We refer to our 2019 Named Executive Officers who did serve through December 31, 2019 as the “Named Executive Officers” throughout the discussion below. References to “2019 Named Executive Officers” include Mr. Abrams. For a detailed discussion of the material terms of Mr. Abrams’ Transition and Retirement Agreement, see “Executive Compensation Tables — Potential Payments Upon Termination orChange-in-Control.”

Executive Summary

Our Business

We are a global provider of instruments, systems, subsystems and process control solutions that measure, monitor, deliver, analyze, power and control critical parameters of advanced manufacturing processes to improve process performance and productivity.productivity for our customers. Our products are derived from our core competencies in pressure measurement and control, flow measurement and control, gas and vapor delivery, gas composition analysis, residual gas analysis, leak detection,electronic control technology, ozonereactive gas generation and delivery, RF & DC power reactive gas generation and delivery, vacuum technology, lasers, photonics,sub-micron positioning, optics, precision motion control, vibration control and optics.laser-based manufacturing systems solutions. We also provide services relating to the maintenance and repair of our products, installation services and training. Our primary served markets include semiconductor, capital equipment, general industrial, life sciences and research.

Company Performance in 2017 and Financial Highlights

2017 was another exceptional year for MKS as revenue and earnings per share, or EPS, both set new Company records. Four years ago, we set a strategy around sustainable and profitable growth. One of the tenets of our strategy was to augment our strong semiconductor market portfolio with acquisitions that broadened our addressable markets. In April 2016, we completed the acquisition of Newport Corporation, or Newport, a global leader in lasers, optics and photonics. This acquisition not only increased our addressable share in our core semiconductor market, but has also given us critical mass to expand into other adjacent, technology intensive and growing markets, including industrial technologies, life and health sciences, and research and defense. Our ability

Company Performance in 2019

The first half of 2019 was challenging for MKS due to successfully integrate Newport into the existing MKS business helped us deliver the 2017 results.

We alsocontinued downturn in our Semiconductor Market, where our customers continued to makeexperience excess production capacity, which drove lower capital expenditures negatively impacting our business. In our Advanced Markets, heightened geopolitical and trade headwinds led to more cautious spending. In addition, the consumer electronics market also underwent a prolonged period of digestion of excess capacity. However, in the second half of the year, we saw improved fundamentals within the Semiconductor Market and stabilization in our Advanced Markets, as trade tensions started to ease. In the fourth quarter of 2019, we delivered strong net revenues of $500 million and experienced strong sequential growth in our Semiconductor Market net revenues, which increased 22% in the quarter. This growth was driven by strong foundry and logic spending, as well as early signs of recovery in memory.

In February 2019, MKS completed the acquisition of Electro Scientific Industries, Inc., or ESI, a worldwide leader in advanced manufacturing processes within the printed circuit board, electronic thin film and electronic component markets. Our acquisition of ESI represents a significant progress addressingstep in broadening our market reach and expanding our addressable market by approximately $2.2 billion. The acquisition also provides MKS with a more balanced portfolio, with approximately 51% of our combined revenue in 2019 coming from Advanced Markets, and 49% from the Semiconductor Market. We expect the addition of ESI to further strengthen our expertise in the lasers, photonics and optics markets, enabling us to develop systems that provide unique and cost-effective solutions to meet the challenges of our customers’ technical requirements. Investmentsevolving technology needs.

In 2019, key results include:

below target. In 2019, the variable cash compensation for all of our executive officers other than Mr. Werth was tied to the financial performance of our Company, as a whole. The Company performance portion of variable cash compensation for Mr. Werth, who heads up our Light and Motion Division, was tied toexcluding the financial performance of our Lightthe Company’s Equipment and Motion Division.

In 2017, our variable cash incentive compensation for all of our Named Executive Officers, other than our Chief Executive Officer, also included an individual performance component with an assigned weighting of 20% of total target variable cash compensation. The Named Executive Officers who were assigned individual performance goals achieved, on average, 188%Solutions Division, which division was formed as a result of the portionCompany’s acquisition of their target variable cash compensation tied to individual performance. Our Compensation Committee did not assign an individual performance component to our Chief Executive Officer’s cash incentive compensation because it believes our Chief Executive Officer should be held accountable for the Company’s overall performance.Electro Scientific Industries, Inc., or ESI, in 2019.

When our Compensation Committee set 20172019 executive compensation in early 2017,2019, long-term equity incentive compensation comprised 64%65% of total target compensation for our Chief Executive Officer and 51%59.2% of total target compensation, on average, for our other Named Executive Officers. Total target compensation is defined as the sum of base salary, target annual cash incentive compensation and target long-term equity incentive compensation. By making equity a substantial component of executive officer compensation, we align our executive officers’ long-term interests with those of our shareholders. Also, at least 50% of each Named Executive Officer’s target long-term equity incentive compensation is based on a measure of Company performance.

Our annual cash incentive plan is designed to complement our long-term equity incentive plan by focusing on our Company’s annual financial performance as measured by adjustednon-GAAP operating income. In 2017,2019, our target annual cash incentive compensation comprised 18%19.1% of total target compensation for our Chief Executive Officer and 22%17.7% of total target compensation, on average, for our other Named Executive Officers.

In 2017,2019, base salary accounted for 18%15.9% of total target compensation for our Chief Executive Officer and 27%23.1% of total target compensation, on average, for our other Named Executive Officers. In 2017,2019, our Chief Executive Officer had 82%84.1% of his total target compensation opportunity tied to annual and long-term incentive compensation and our other Named Executive Officers, on average, had 73%76.9% of their total target compensation opportunity tied to annual and long-term incentive compensation.

Consideration of 20172019 Advisory Vote on Executive Compensation

At our 20172019 Annual Meeting of Shareholders, held on May 10, 2017,8, 2019, we submitted to our shareholders an advisory vote on executive compensation. Although annual advisory“say-on-pay” votes arenon-binding, our Compensation Committee has considered, and will continue to consider, the outcome of this vote each year when making compensation decisions for our Named Executive Officers. At the 20172019 Annual Meeting, our shareholders overwhelmingly approved theour executive compensation, of our Named Executive Officers, with approximately 96%96.5% of the votes cast voting in favor of the“say-on-pay” proposal.

The Compensation Committee considered the results of the 20172019say-on-pay vote, and based upon the strong shareholder support, does not believe that our executive compensation program requires material changes. The Compensation Committee will continue to consider the views of our shareholders in connection with our executive compensation program and will consider changes based upon evolving best practices, market compensation information and changing regulatory requirements. The Compensation Committee believes that the 20172019 shareholder vote was an endorsement of our compensation and the pay decisions made in relation to our performance.

Compensation Philosophy and Objectives

The primary objectiveobjectives of our executive compensation program is to are to:

We target each of the various compensation elements, including base salary, annual cash incentive compensation, and long-term equity incentive compensation, to be within a competitive range around median levels for the individual position in the market. However, thisThe competitive range is merely one factor that the Compensation Committee considersconsidered alongside other key factors when setting compensation levels, and we do not set any specific element or total compensation exactly to the median and, in certain cases, we will and do pay total compensation closer tofinal values may range from approximately the 25th andpercentile to approximately the 75th percentiles whenpercentile, as appropriate. In considering the compensation of our Named Executive

Officers relative to the market, we also look qualitatively at the individual’s overall performance, tenure and potential with MKS.contributions to MKS’ ongoing growth. Currently, all of our Named Executive Officers are paid within the competitive range of our peer group.

Base salaries are designed to provide executives with a level of predictability and stability with respect to a portion of their total compensation package. Base salaries are a relatively small component in the overall pay packages of our Named Executive Officers because we believe the significant majority of executive compensation should be variable and based on performance.

Our annual cash incentive compensation program provides a short-term incentiveis designed to reward management for reaching our annualthe attainment of short-term earnings goals and, in certain cases, individual performance objectives, and to reinforce ourpay-for-performance philosophy.that drive the long-term growth of MKS. We believe that our program providesgoals are aligned with significant value creation, and that our plan creates a strong link between pay and performance while providing meaningful incentive for our Named Executive Officers to exceed our financial goals.

We provide our Named Executive Officers with long-term equity incentive compensation in the form of restricted stock units, or RSUs, approximately half of which are performance-based, in order to:

The following charts show the components of total target compensation for our Chief Executive Officer and our other Named Executive Officers as a group for calendar year 2017.2019.

When the Compensation Committee met in October 2016July 2018 to review peer companies to be used to determine 20172019 executive compensation, the Committee elected to make no changes were made to the listpeer group with the exception of Microsemi Corporation, which was removed because it was acquired by Microchip Technology, Inc. in 2018. The 18 peer companies used to determine 2016 executive compensation. These peer companies had beenwere selected in May 2016, following the closing of our acquisition of Newport, based on similar industry, market capitalization and revenue, with a revenue and market capitalization range relative to our projectedtrailing12-month revenue as of June 30, 2018 of between 0.4 times and 2.0.3 to 3 times. The Compensation Committee engaged its independent compensation consultant, Meridian, to prepare a competitive compensation analysis for each of our executives on aposition-by-position basis based on estimated revenue and market capitalization of the combined company of $1.4 billion and$2.5-$3.0 billion, respectively. Publicly available compensation data from the following comparable peer companies was used in determining executive compensation for 2017:2019:

Our Compensation Committee also considered size and industry-appropriate broad survey data from the 20172019 Radford Global Technology Survey.

Our executive compensation program is guided by the following principles:

Elements of Compensation

The following summarizes the compensation elements for our Named Executive Officers:

Base Salary

When our Compensation Committee set 20172019 annual executive compensation in early 2017,February 2019, it approved a salary increase of approximately 3%4% for each of Mr. Colella, our former Chief Executive Officer, Dr. Lee, our President and Chief Executive Officer, Mr. Bagshaw, our Senior Vice President, Chief Financial Officer and Chief Operating Officer,Treasurer, and a salary increase of approximately 12% for each ofMs. Burke, our Senior Vice President, of Global SalesGeneral Counsel and Service and our Senior Vice President of Business Units.Secretary. These increases were based on the compensation data collected from our peer group.

Annual Cash Incentive Compensation

Our annual cash incentive compensation program consists of our shareholder-approved executive cash incentive plan, which is calledFor 2019, the 162(m) Plan, andCompensation Committee did not make any changes to our annual cash incentive plan.

Pursuantprogram compared to the terms of the 162(m) Plan, our Compensation Committee established an “umbrella” formula to determine aggregate funding for the plan based on the achievement of a specific,pre-determined Company financial performance goal. Under the umbrella formula, each Named Executive Officer was allocated a share of an incentive pool based on our adjusted operating income for the 2017 fiscal year (defined as GAAP operating income adjusted for restructuring charges, acquisition or divestiture related costs and the effect of acquisitions and divestitures). The Compensation Committee exercises negative discretion from this 162(m) pool by applying the goals of our annual cash incentive plan as described below.

2018. Under our annual cash incentive plan, each Named Executive Officer was eligible to receive a performance bonus based on a specified percentage of eligible earnings, which is defined as eligibleW-2

earnings received during the 20172019 calendar year (i.e., base salary, including regular, holiday, vacation and sick pay, but excluding bonus payments). Bonus payouts in 20172019 were based 80% on a Company financial performance objective and 20% on individual performance objectives for all Named Executive Officers other than our Chief Executive Officer, whose annual executive bonus was based entirely on Company financial performance.non-GAAP operating income after bonus and excluding any charges or income not related to the operating performance of the Company.

In 2017, each Named Executive Officer was eligible to receive 50% of his target bonus attributable to the Company performance objective if the minimum threshold was achieved. If we had achieved our target results, each such Named Executive Officer would have been eligible to receive 100% of his target bonus attributable to

the Company performance objective, up to a maximum of 200% for achievement in excess of the target results, with proportional2019, payouts for performance between these levels. In the event the minimum threshold for the Company financial performance objective was not met, but would have been met but for the payment of these bonuses, then in such case a pro rata portion of the bonus would be paid to each such Named Executive Officer, but only to the extent that the Company financial performance objective after such payment was no less than the minimum Company financial performance objective.

In 2017, payouts for Company financial performance under the annual cash incentive plan were determined by multiplying a Named Executive Officer’s “Target Bonus Amount” by the “Company Performance Multiplier,”Company’s percentage achievement of the financial performance objective, each as discussed below. Target Bonus Amount is the amount determined by multiplying each Named Executive Officer’s eligible earnings in 20172019 by the Target Bonus Percentages determined by our Compensation Committee each year. When our Compensation Committee set 20172019 annual executive compensation in early 2017,2019, it did not approve any increaseschanges to Target Bonus Percentages for our Named Executive Officers.Officers compared to 2018.

Listed below is the 20172019 Target Bonus Percentage for each Named Executive Officer.

In 2017, the Company Performance Multiplier, which is a percentage, was based upon2019, our achievement of adjustedCompensation Committee approved goals and associated incentive payout opportunities related to our 2019non-GAAP operating income after bonusperformance. As we operate in the highly cyclical semiconductor market, our Compensation Committee views it of paramount importance to set performance goals that are rigorous but attainable given the outlook for the semiconductor market and excluding special items. Participants,the other than Mr. Werth,markets in which we serve for the coming year. The rigor of our performance goals for 2019 is evidenced by the fact that our funding for the 2019 annual incentive plan was below target despite the fact we had a strong performance year.

In 2019, participants in the annual cash compensation plan would not receive any portion of their Target Bonus Amount tied to Company financial performance if such adjustednon-GAAP operating income (before the calculation of bonus) was less than the minimum threshold of $175.0$195.9 million. The Company Performance MultiplierParticipants would bereceive 50% of a Participant’stheir Target Bonus Amount if such adjustednon-GAAP operating income was $175.0$195.9 million, would bereceive 100% of their Target Bonus Amount if such adjustednon-GAAP operating income was $245.2$391.7 million, and would bereceive the maximum 200% if such adjustednon-GAAP operating income was $367.9$550.3 million or more, with proportional payments for achievement in between these levels. In 2017,2019, because our adjustednon-GAAP operating income, after bonus and excluding amortization of intangible assets, restructuring charges, acquisition and divestiture related costs and related term loan fees and costs, integration costs, a legal settlement, impairment of investment charges, a gain on the effectsale of acquisitionsproperty, executive retirement costs, and divestitures,costs related to unanticipated tariffs and trade restrictions, was $429.2$355.2 million, participants were eligible to receive 200%91% of their Target Bonus Amounts tied to Company financial performance under this formula. For Mr. Werth, the 2017 Company Performance Multiplier was based on the Light and Motion Division’s achievement of adjusted operating income after bonus and excluding special items. Mr. Werth would not receive any portion of his Target Bonus if such adjusted operating income was less than the minimum threshold of $51.2 million. The Company Performance Multiplier would be 50% of Mr. Werth’s Target Bonus Amount if such adjusted operating income was $51.2 million, would be 100% if such adjusted operating income was $71.8 million, and would be the maximum 200% if such adjusted operating income was $107.7 million or more, with proportional payments for achievement in between. In 2017, because the Light and Motion Division’s adjusted operating income, after bonus and excluding restructuring charges, acquisition and divestiture related costs and the effect of acquisitions and divestitures, was $116.4 million, Mr. Werth was eligible to receive 200% of his Target Bonus Amount under this formula.

In 2017, individual performance was measured using specific “management by objective” goals, or MBOs, that were aligned to our strategic objectives and priorities and each Named Executive Officer’s business unit or function. Our Chief Executive Officer developed the MBOs for his direct reports with a focus on the measurable accomplishments in their individual areas of responsibility that will benefit our shareholders over the long term.

Listed below is a summary of each Named Executive Officer’s performance against his 2017 MBOs.

Except as described above.

For 2018, thenoted below, our Compensation Committee made the following twodid not make any design changes to our 2020 annual cash incentive program:

With the exception of these two changes, the design of our 2018 annual cash incentive program is similar to 2017. For all Named Executive Officers other than Mr. Werth,eligible participants, Company performance will be measured using the same financial metric as in previous years –non-GAAP operating income after bonus and excluding special items. For Mr. Werth, Companyany charges or income not related to the operating performance will continue to be measured using Light and Motion Division’s achievement ofnon-GAAP operating income after bonus and excluding special items. the Company.

OurIncorporation of Profit Improvement Bonus Plan for Calendar Years Beginning in 2020

In February 2020, our Board of Directors, upon the recommendation of our Compensation Committee, hasapproved a profit improvement component to our annual cash incentive plan designed to incentivize profitability improvements during cyclical downturns in our business. Individuals who are eligible to participate in our annual incentive bonus plan are also eligible for the authority to make otherprofit improvement cash bonus awardsplan. In order to receive any payout under this plan, MKS must achieve specified profit enhancements or cost reductions by the end of the applicable calendar year. A participant’s maximum bonus under this plan is 25% of his or her eligible earnings (using the same definition as used in our Named Executive Officers as it deems appropriate. No otherannual cash incentive plan). Participants are only eligible to receive a payout under the profit improvement cash bonus awards were madeplan if the participant receives less than 100% of his or her Target Bonus Amount under our annual incentive bonus plan, and any payout under the profit improvement cash bonus plan is capped such that the combined payout under our annual incentive bonus plan and under the profit improvement cash bonus plan will not exceed an amount equal to 100% of the participant’s Target Bonus Amount under our Named Executive Officers in 2017.annual incentive bonus plan.

Long-Term Equity Incentive Compensation

When our Compensation Committee set 20172019 annual executive compensation in early 2017,2019, it awarded the following time-based and performance-based RSUs to our Chief Executive Officer and our other Named Executive Officers. These RSUs vest in three equal annual installments. The performance-based RSUs are subject to aone-year performance metric described below.

With respect to performance-based RSUs, our goal is to select a Company financial performance metric that best aligns with our Company objectives. Recently, including in 2017,2019, our Company financial performance metric for performance-based RSUs has been adjustednon-GAAP cash flow from operations (defined as net income plus depreciation, amortization andnon-cash stock-based compensation and excluding special items set forth in Section 9(c)(i) through (xiv)any charges or income not related to the operating performance of our 2014 Stock Incentive Plan)the Company) set at varying revenue levels. We believeOur Compensation Committee believes this financial metric is an appropriate indicator of how welleffectively we manage the operations of our Company.Company in light of the cyclical nature of the markets we serve as well as providing incentives to continuously improve our financial operating model independent of revenue levels.

We use RSUs as our form of equity incentive compensation because we believe RSUs help to ensure that our executive officers’ interests are aligned with our shareholders’ interests in both a rising and a declining stock market. We believe RSUs are preferable to options, which have a relatively high accounting cost as compared to their potential value to the executive officer, and are preferable to restricted stock, which gives the executive officer voting and dividend rights prior to full vesting. Also, because RSUs are worth more than options on the date of grant, we are able to grant fewer of them thanthese as compared to options, resulting in less dilution to shareholders’ holdings.

In 2017,2019, our Named Executive Officers would have forfeited all of their performance-based RSUs if our adjustednon-GAAP cash flow from operations was less than $148.0$264.9 million at a revenue level of $1.25$1.5 billion, or if such

cash flow was less than $355.5$448.8 million at a revenue level of $2.0$2.3 billion (with intermediate adjustednon-GAAP cash flow minimum thresholds at different revenue levels in between). However, if we did achieve these adjustednon-GAAP operating cash flow threshold levels at the respective revenue levels identified, our Named Executive Officers would receive 50% of their target performance-based RSUs. If our adjustednon-GAAP cash flow from operations was at or above $199.7$357.5 million at a revenue level of $1.25$1.5 billion, or was at or above $479.9$605.7 million at a revenue level of $2.0$2.3 billion (with proportional thresholds in between), then our Named Executive Officers would receive the maximum of 150% of their target performance-based RSUs. Proportional paymentsachievement levels would be made for adjustednon-GAAP cash flow achievements between the minimum and maximum levels. In 2017,2019, because our revenue was $1.9$1.73 billion, after excluding revenue from our Equipment and Solutions Division, which was formed as a result of our acquisition of ESI in 2019, and including revenue amounts unrecorded due to trade restrictions, and our adjustednon-GAAP cash flow was $413.9$343.4 million, after excluding restructuring charges, acquisitionexecutive retirement costs, costs related to tariff and divestiture relatedtrade restrictions, a legal settlement, acquisition costs and related term loan fees and costs, integration costs, impairment of investment charges, a gain on the sale of property, and the tax effect of acquisitionseach of these excluded costs, in addition to amortization of intangible assets, depreciation of fixed assets, stock-based compensation expense and divestitures, andtax adjustments resulting from additional guidance from the effect of changes inIRS regarding 2017 tax laws,reform, our Named Executive Officers received 121%82% of their target performance-based RSUs. These performance-based RSUs, along with the time-based RSUs granted to our Named Executive Officers, vest in equal annual installments over three years from the original date of grant.

It is our practice to make an initial equity-based grant to all of our Named Executive Officers at the time they commence employment in an amount that is consistent with amounts granted to other executive officers in the industry at similar levels of seniority. In addition, we typically make an annual grant of equity-based compensation to our Named Executive Officers during the first fiscal quarter of each year. Discretionary equity-based grantsawards may also be made throughout the year to provide an incentive to achieve a specific goal or to reward a significant achievement. achievement or for other reasons that the Compensation Committee determines. In October 2019, our Compensation Committee made a discretionary equity-based award to two of our Named Executive Officers as set forth below.

Compensation Tables — Retirement and President.

Post-Employment Tables — Pension Benefits” below for a description of the supplemental retirement benefits we provide to Mr. Colella. Since 2011, it has been our policy not to offer these types of retirement benefits to other Named Executive Officers.executive officers. While these benefits were attractive elements to retain certain of our most senior executive officers historically, the elimination of these benefits more closely meets our objective to align executive compensation with Company financial performance.

Newport Deferred Compensation Plan

In connection with the Newport acquisition in April 2016, we assumed Newport’s Deferred Compensation Plan. Historically, Mr. Werth has made elections to defer a portion of his compensation into this plan. He did not make such an election in 2015 for 2016 compensation. In 2016, Newport employees who were eligible to participate in the plan were not permitted to make an election for the deferral of any of their salaries in 2017 but did have the opportunity to make an election to defer their 2017 annual incentive compensation to the extent earned and paid in 2018. Mr. Werth elected to defer 100% of his 2017 annual incentive compensation. No further elections will be permitted under this plan.

Perquisites

We offer certain perquisites to our executive officers, including our 2019 Named Executive Officers, to allow executives to focus on corporate strategy and enhancing shareholder value and to provide competitive pay packages. These perquisites include car payments, company paid health and life insurance, reimbursement of certainout-of-pocket healthcare costs, golf club memberships, financial planning benefits and executive physicals. We believe offering these benefits is important to maintaining a competitive position in attracting and retaining key personnel and these benefits are consistent with market practices.

Severance andChange-in-Control Provisions

Each of our Named Executive Officers is entitled to certain payments and benefits in the event his or her employment terminates under specified circumstances as described in the applicable agreement. In exchange for these payments and benefits, each Named Executive Officer other than Mr. Werth, whose agreement is governed by California law, is restricted from competing with the Company during and following his or her termination of employment for a twelve-month period. In addition, RSU agreements with our Named Executive Officers or in Mr. Werth’s case, solely with respect to certain of his RSU agreements, provide for acceleration of vesting in the event the executive’s employment is terminated without cause or the executive resigns for good reason within 24 months after achange-in-control. The severance andchange-in-control provisions are designed to be competitive in the marketplace, to provide security for our Named Executive Officers in the event that we are acquired and his or her respective position is impacted and to provide an incentive for the Named Executive Officer to stay with us through such achange-in-control event. These provisions are also intended to protect us from competitive harm, by compensating our Named Executive Officers for agreeing to substantialnon-compete provisions after employment termination. See “Executive Compensation Tables — Potential Payments Upon Termination orChange-in-Control” for more information about these agreements.

Transition and Retirement Agreement

On May 9, 2018, Mr. Abrams entered into a Transition and Retirement Agreement with the Company. Mr. Abrams retired on February 28, 2019. Mr. Abrams’ Transition and Retirement Agreement superseded and replaced the Employment Agreement that he entered into with the Company effective August 1, 2016. For a detailed discussion of the material terms of the Transition and Retirement Agreement, see “Executive Compensation Tables — Potential Payments Upon Termination orChange-in-Control.”

Compensation of our Chief Executive Officer

We entered into an employment agreement with Mr. Colella upon his becoming Chief Executive Officer and President in January 2014. The terms of Mr. Colella’s employment agreement reflectreflected his role as the leader of our Company and the experience he brought to the position having served more than 30 years at MKS. For a detailed discussion of the material terms of Mr. Colella’s employment agreement, including all amendments to this employment agreement, see “Executive Compensation Tables — Potential Payments Upon Termination orChange-in-Control.”

Compensation of our Other Named Executive Officers

We have entered into employment agreements with each of our other Named Executive Officers. For a detailed discussion of the material terms of these executive employment agreements, including all amendments to these employment agreements, see “Executive Compensation Tables — Potential Payments Upon Termination orChange-in-Control.”

Compensation Consultant

We engage a compensation consultant to serve as an independent advisor to the Compensation Committee regarding compensation for our directors and our executive officers. The Compensation Committee utilizes the compensation consultant in the following ways:

SinceFrom October 2014 through May 2019, the Compensation Committee has engaged Meridian as its compensation consultant. The Compensation Committee determined that the engagement of Meridian as a compensation consultant did not raise any conflicts of interest with MKS. In May 2019, the Compensation Committee elected to engage a new compensation consultant, Pearl Meyer. The Compensation Committee has determined that the engagement of Pearl Meyer as a compensation consultant does not raise any conflicts of interest with MKS.

Role of our Chief Executive Officer

Our Chief Executive Officer reviews with the Compensation Committee the performance of all other Named Executive Officers and makes recommendations relating to compensation of such executive officers. Management develops proposed company financial goals for review and approval by the Compensation Committee for the annual cash incentive plan and long-term performance-based equity incentive compensation, develops proposals relating to potential changes in compensation programs for review and approval by the Compensation Committee and provides the Compensation Committee and its advisors with information necessary to evaluate and implement compensation proposals and programs. Our Chief Executive Officer does not participate in discussions regarding his own compensation.

Governance Policies

Stock Ownership Guidelines

OurThe Stock Ownership Guidelines for 2019, which arewere applicable to members of the Board of Directors, the Chief Executive Officer and any other person who is or was a Named Executive Officernamed executive officer while the guidelines arewere effective, provideprovided that: