DEF 14A of MKS Inc, Mar 31, 2026

DEF 14A of MKS Inc

Filed Mar 31, 2026 · FY20250001193125-26-133378

Open on EDGAR

  1. TO BE HELD ON MONDAY, MAY 11, 2026 at 10:00 A.M. EASTERN TIME

    | CEO Pay Ratio | 79 | | Pay Versus Performance | 80 | | EQUITY COMPENSATION PLAN INFORMATION | 84 | | OTHER MATTERS | 85 | | Expenses and Solicitation | 85 | | Deadline for Submission of Shareholder Proposals for the 2027 Annual Meeting | 85 | | Householding of Annual Meeting Materials | 85 | | No Incorporation by Reference | 86 | | APPENDIX A | A-1 | | Amended and Restated 2022 Stock Incentive Plan | A-1 | | APPENDIX B | B-1 | | Reconciliation of 2025 Income from Operations to 2025 Non-GAAP Operating Income | B-1 | | Reconciliation of 2025 Gross Debt to 2025 Adjusted Net Debt | B-1 | | Reconciliation of 2025 Net Income to 2025 Adjusted EBITDA | B-1 |

  2. PROPOSAL 1 – ELECTION OF DIRECTORS

    PROPOSAL 1 – ELECTION OF DIRECTORS Our Board of Directors is currently divided into three classes. The term of the current Class III Directors expires at the 2026 Annual Meeting, the term of the Class I Directors expires at the 2027 Annual Meeting of Shareholders, or the 2027 Annual Meeting, and the term of the Class II Directors expires at the 2028 Annual Meeting of Shareholders, or the 2028 Annual Meeting. Pursuant to our By-Laws, our Board of Directors will be declassified over a three-year period beginning with the 2026 Annual Meeting, resulting in the Board being fully declassified (and all directors standing for annual elections) beginning with the 2028 Annual Meeting. Our Board of Directors, upon the recommendation of our Nominating and Corporate Governance Committee, has nominated Peter J. Cannone III, Joseph B. Donahue and Wissam G. Jabre (our current Class III Directors) to serve as Directors for a term to expire at the 2027 Annual Meeting. Mr. Cannone, Mr. Donahue, and Mr. Jabre currently serve as directors. Each nominee has consented to being named herein and, if elected, to serve as a director until his 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 any 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 PETER J. CANNONE III, JOSEPH B. DONAHUE AND WISSAM G. JABRE TO SERVE AS DIRECTORS IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” ALL NOMINEES.

  3. DIRECTORS

    DIRECTORS Set forth below are the names and ages of each member of our Board of Directors (including those who are nominees for election) and the positions and offices they hold with the Company. In addition, set forth below are biographies for each continuing director and director nominee, which include information about each individual’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 individual, directly or indirectly, as of March 3, 2026, appears in this proxy statement under the heading “Security Ownership of Certain Beneficial Owners and Management.”

  4. DIRECTORS

    | Name | Age | Position | Audit Committee | Compensation Committee | Nominating and Corporate Governance Committee | Class to Which Director Currently Belongs | | Rajeev Batra | 58 | Director | | | | I | | Peter J. Cannone III* | 60 | Director | | | | III | | Gerald G. Colella | 69 | Chair | | | | I | | Joseph B. Donahue* | 67 | Director | | | | III | | Wissam G. Jabre* | 56 | Director | | | | III | | John T.C. Lee | 63 | Director, President and CEO | | | | II | | Jacqueline F. Moloney | 72 | Lead Director | | | | II | | Elizabeth A. Mora | 65 | Director | | | | I |

  5. DIRECTORS

    Chair Member * Nominee for election at the 2026 Annual Meeting

  6. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 5 |

  7. DIRECTORS

    | | Rajeev Batra Chief Executive Officer, Eptura, Inc. | | Age: 58 Director since: 2018 Independent | Standing Committees: Compensation (Chair); Nominating and Corporate Governance |

  8. DIRECTORS

    | Background | | Mr. Batra has served as Chief Executive Officer of Eptura, Inc., a global software workplace technology company that provides software solutions to manage workplaces, people, and assets, since September 2025. He also has served as the co-founder and Chairman of AxD LLC, a consulting firm specializing in automation and digitization, since 2024. Mr. Batra is a former Siemens U.S. executive who, over a 30+ year career, progressed from an individual contributor in 1993 to a wide range of high-level management, strategy and sales positions, culminating in his role as President of Siemens Digital Industries U.S., an innovation pioneer in industrial automation and digitalization in the discrete and process industries, from 2019 to 2023. He also served as President of Siemens Industry Inc. from 2023 to 2024 and a member of the Siemens U.S. Managing Board from 2021 to 2024, as well as President of the Digital Factory Division from 2014 to 2019; President of the Industry Automation Division from 2009 to 2014; Vice President and General Manager of the Automation & Motion Division from 2007 to 2009; and Vice President and General Manager of the Automotive & Aerospace Vertical Markets from 2002 to 2007, all for Siemens U.S. Mr. Batra has served as a director of Q-mation, a private company that provides industrial automation software, hardware, and services, since 2025, an executive advisor to Kearney, a global management consulting firm, since 2024, an advisory board member of Advanced Technology Services, Inc., a private, global services provider for industrial maintenance, technology and parts, since 2024, a director of Amsted Industries, a private, global manufacturer of industrial components, since 2019, and a member of the Executive Committee of the Manufacturers Alliance, a non-profit manufacturing leadership network, since 2016. Mr. Batra previously served as a director of Shapeways Holdings, Inc. from 2022 to 2024 and Chair and Member of the Board of Governors of the National Electrical Manufacturers Association (NEMA), a trade association of electrical equipment manufacturers, from 2014 to 2023. Mr. Batra holds a B.S. in Electrical Engineering from Lawrence Technological University and an M.B.A. from the University of Michigan. | | Key Qualifications as Determined by our Board of Directors | | • Significant management and leadership experience, cultivated over 25+ years in senior roles in broad global industrial markets • Extensive technology background, including in automation, industrial software, digitalization, OT/IT convergence, cybersecurity, and I4.0/IoT • Proven ability to develop and grow product, systems, digital services, and turnkey businesses in the Process and Discrete Markets, and founding Siemens’ Automotive & Aerospace Vertical Markets in the United States |

  9. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 6 |

  10. DIRECTORS

    | | Peter J. Cannone III Chief Executive Officer, Newforma, Inc. | | Age: 60 Director since: 2021 Independent | Standing Committees: Audit |

  11. DIRECTORS

    | Background | | Mr. Cannone has served as Chief Executive Officer and a member of the Board of Directors of Newforma, Inc., a technology company that provides project information management and collaboration software for the architecture, engineering, construction, and owner/operator industries, since April 2025, continuing a long career as a senior executive for large and mid-market public and private technology companies in both growth and turnaround modes. His previous experience includes serving as Chairman and Chief Executive Officer of Demand Science Group, LLC, a leading global revenue intelligence platform delivering a comprehensive suite of business-to-business solutions, from 2020 to 2024; General Partner of Optum Ventures, a healthcare-focused venture capital firm, from 2019 to 2020; Chief Executive Officer of UpCurve, Inc., a management company, where he oversaw portfolio firms that provided critical digital, cloud, financial and healthcare solutions to small and midsize businesses, from 2018 to 2019; Chief Executive Officer of ThriveHive, a provider of digital marketing services and one of UpCurve’s portfolio firms, from 2015 to 2019; President and Chief Executive Officer of OnForce, a leading vendor of SaaS technology-enabled workforce solutions, from 2007 to 2014; and a member of senior management at PC Connection, Inc. and MicroWarehouse from 1997 to 2006. Mr. Cannone holds a B.A. in Economics from the University of Massachusetts, Amherst and an M.B.A. from Rensselaer Polytechnic Institute. | | Key Qualifications as Determined by our Board of Directors | | • Proven leader of public and private technology companies with 25+ years of experience in executive and senior management roles • Direct knowledge of and experience in mergers and acquisitions, capital raising, marketing, and financial planning and analysis • Track record of building high-performance teams and developing executives |

  12. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 7 |

  13. DIRECTORS

    | | Gerald G. Colella Chair of the Board and Former CEO, MKS Inc. | | Age: 69 Director since: 2014 Independent | Other Current Public Company Directorships: Columbus McKinnon Corporation (Chair of the Board) |

  14. DIRECTORS

    | Background | | After joining MKS in 1983, Mr. Colella progressed from positions in materials planning and logistics to leading our global business and service operations before assuming senior management roles, including Vice President and Chief Business Officer, President and Chief Operating Officer and, ultimately, Chief Executive Officer. As CEO from 2014 until his retirement in 2020, he steered MKS through a period of unprecedented growth, increasing MKS’ revenue from approximately $780 million to over $2 billion. Since 2020, Mr. Colella has served as Chair of our Board of Directors. Mr. Colella holds a B.A. in Secondary Education from the University of Massachusetts Lowell and an M.B.A. from Southern New Hampshire University. | | Key Qualifications as Determined by our Board of Directors | | • Deep insights into our business, industries and markets as a result of a 35+ year career at MKS, culminating as CEO • Direct knowledge of and experience in operations, marketing, business strategy, and growth, organically and through acquisitions • Extensive background in leadership, management, and governance at the most senior levels of a public company |

  15. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 8 |

  16. DIRECTORS

    | | Joseph B. Donahue Former EVP and COO, TE Connectivity Ltd. | | Age: 67 Director since: 2020 Independent | Standing Committees: Audit; Nominating and Corporate Governance |

  17. DIRECTORS

    | Background | | Mr. Donahue served as Executive Vice President and Chief Operating Officer of TE Connectivity Ltd. (formerly Tyco Electronics Ltd.), a publicly held manufacturer of connectors, sensors, and minimally invasive surgical assemblies for the automotive, industrial, medical, aerospace, and communications/consumer markets, from 2011 until 2017. In this role, Mr. Donahue was responsible for all aspects of corporate global operations, including supply chain, manufacturing, environment, health and safety, facilities, technology, and lean process improvement. He concurrently served as President of the Network Solutions segment of TE Connectivity from 2012 until the divestiture of that business in 2015. He also served at TE Connectivity as President, Transportation Solutions segment from 2010 through 2012, President of the Global Automotive Division from 2008 through 2009, and Senior Vice President of the same division beginning in 2007. From 2006 to 2007, he was Group Vice President, Wood Coatings Division, for Valspar Corporation, a manufacturer of commercial and industrial coatings. Over the prior 16 years, Mr. Donahue held a variety of senior management roles at TE Connectivity and AMP Incorporated. Mr. Donahue previously served as a director of Kraton Corporation, a private, global sustainable producer of specialty polymers and high-value biobased products derived from pine wood pulping co-products, from 2023 to 2025. Mr. Donahue holds a B.S. in Biological Sciences and an M.S. in Plastics Engineering from the University of Massachusetts Lowell. He also holds an M.S. in Manufacturing Systems Engineering from Lehigh University. | | Key Qualifications as Determined by our Board of Directors | | • Extensive experience in executive leadership roles for companies serving multiple markets, including industrials • Valuable insights into managing all aspects of global operations and overseeing mergers and acquisitions • Deep understanding of international organizations, having lived and worked in Japan, China, and Germany |

  18. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 9 |

  19. DIRECTORS

    | | Wissam G. Jabre EVP and CFO, NetApp, Inc. | | Age: 56 Director since: 2024 Independent | Standing Committees: Audit |

  20. DIRECTORS

    | Background | | Mr. Jabre has served as Executive Vice President and Chief Financial Officer of NetApp, Inc., an intelligent data infrastructure company that provides unified data storage, integrated data services and cloud operations solutions, since March 2025. Previously, Mr. Jabre served as Executive Vice President and Chief Financial Officer of Western Digital Corporation, a leading developer, manufacturer, and provider of data storage devices, from 2022 to February 2025. Prior to that, Mr. Jabre served as Senior Vice President and Chief Financial Officer of Dialog Semiconductor Plc, a provider of semiconductor-based system solutions, from 2016 until it was acquired by Renesas Electronics Corporation in 2021. Mr. Jabre previously served as Corporate Vice President of Finance at Advanced Micro Devices, Inc., from 2014 to 2016. Prior to 2014, he served in various finance leadership positions at Freescale Semiconductor, Inc. (acquired by NXP Semiconductors N.V.). Mr. Jabre holds a B.E. in Electrical Engineering from the American University of Beirut and an M.B.A. from Columbia Business School. He is a CFA© charterholder. | | Key Qualifications as Determined by our Board of Directors | | • Demonstrated leader in financial oversight, risk management, and strategic planning as CFO of three major companies • Strong familiarity with our business from 20+ years of experience in the semiconductor industry • Valuable combination of financial and accounting expertise and engineering background |

  21. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 10 |

  22. DIRECTORS

    | | John T.C. Lee President and CEO, MKS Inc. | | Age: 63 Director since: 2020 | Other Current Public Company Directorships: Cognex Corporation |

  23. DIRECTORS

    | Background | | Dr. Lee has served in progressive leadership roles since joining MKS in 2007, culminating in his appointment as our President and Chief Executive Officer in 2020. He previously served as our President from 2019 to 2020; our President and Chief Operating Officer from 2018 to 2019; our Senior Vice President and Chief Operating Officer from 2016 to 2018; our Senior Vice President of Business Units from 2014 to 2016; our Senior Vice President, Controls, HPS (our integrated process solutions business) and Pressure, Flow, Measurement and Control (PFMC) from 2012 to 2013; our Senior Vice President, Controls and PFMC from 2011 to 2012, and our Group Vice President, Controls and Information Technology products from 2007 to 2011. Prior to MKS, Dr. Lee served in leadership roles at Applied Materials, a global leader providing processing equipment to the semiconductor and display markets, from 2002 to 2007, including Managing Director of Factory Technology and Projects within the Solar Business Group and General Manager of the Cleans Product Group and the Maydan Technology Center. Prior to Applied Materials, Dr. Lee served as Research Director of the Silicon Fabrication Research Department at Lucent Technologies, Inc., a voice, data, and video communications provider, from 1997 to 2002 and as a Member of the Technical Staff in the Plasma Processing Research Group within Bell Labs from 1991 to 1997. In addition to the other current public company directorship listed above, he has served as Co-Chair of the Mass Opportunity Alliance since 2024 and a member of the Executive Committee of the Board of Directors of the Massachusetts High Technology Council (MHTC) since 2021. He previously served as Chair of MHTC from 2023 to 2025 and as Vice Chair of MHTC from 2021 to 2023. Dr. Lee holds a B.S. from Princeton University and both an M.S.CEP and a Ph.D. from the Massachusetts Institute of Technology, all in Chemical Engineering. | | Key Qualifications as Determined by our Board of Directors | | • Deep understanding of our extensive and complex product portfolio, driven by strong technical education and background • Unique leadership perspective from progressive leadership roles at MKS and Applied Materials, one of our largest customers • Direct knowledge of and experience in engineering, operations, mergers and acquisitions, and business development |

  24. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 11 |

  25. DIRECTORS

    | | Jacqueline F. Moloney Professor and Chancellor Emerita, the University of Massachusetts Lowell Lead Director | | Age: 72 Director since: 2016 Independent | Standing Committees: Compensation; Nominating and Corporate Governance (Chair) |

  26. DIRECTORS

    | Background | | Dr. Moloney is a Professor and Chancellor Emerita at the University of Massachusetts Lowell who has been recognized as a national leader in innovation and entrepreneurship in higher education. During a nearly 40-year career at UMass Lowell, a public university with approximately 17,000 students, Dr. Moloney served as Chancellor from 2015 to 2022, Executive Vice Chancellor from 2007 to 2015, and Dean of Online and Continuing Education from 1994 to 2007, in addition to serving as a Professor since 1986. Dr. Moloney has over 35 years of experience as a leader in non-profit organizations. In recognition of her leadership and business acumen, she was recognized in 2024 as one of the top five college presidents since 2000 by the American Enterprise Institute. In addition, she and UMass Lowell were recognized in the top 20 of the Boston Globe’s Top 100 Women-Led Businesses for five consecutive years, she was recognized as one of seven prominent “Women Who Mean Business” by the Boston Business Journal, she was selected by the Massachusetts Technology Leadership Council as a finalist for the CEO of the Year award in 2018 and 2019, and she was named Chief Executive HR Champion by the College and University Professional Association for Human Resources in 2018. Dr. Moloney previously served as a director of Enterprise Bancorp, Inc. from 2008 to 2025 and a member of the Board of Directors of the Massachusetts High Technology Council from 2015 to 2022. Dr. Moloney holds a B.S. in Sociology from UMass Lowell, an M.A. in Social Psychology from Goddard College, and an Ed.D. from UMass Lowell. | | Key Qualifications as Determined by our Board of Directors | | • Valuable knowledge of and insights into emerging strategic planning and management and business trends • Deep history of working with business and industry, including establishing incubators at UMass Lowell for early-stage companies • Strong leadership and interpersonal skills and business acumen |

  27. DIRECTORS

    | MKS INC. | 2026 PROXY STATEMENT | 12 |

  28. DIRECTORS

    | | Elizabeth A. Mora Former Chief Administrative Officer, The Charles Stark Draper Laboratory, Inc. | | Age: 65 Director since: 2012 Independent | Standing Committees: Audit (Chair); Compensation Other Current Public Company Directorships: Inogen, Inc. (Chair of the Board); Limoneira Company |

  29. DIRECTORS

    | Background | | Over her 30+ year career, Ms. Mora established herself as a financial and accounting expert and business operations leader, culminating in her role as Chief Administrative Officer of The Charles Stark Draper Laboratory, Inc., a non-profit engineering innovation company, from 2016 to 2020. Ms. Mora was previously Chief Financial Officer of Draper Labs; Chief Financial Officer and Vice President for Finance of Harvard University; Associate Vice President, Research Administration and the Director of the Office of Sponsored Research of Harvard University; and a founding member of the National Regulatory Consulting Practice at Coopers & Lybrand (now PricewaterhouseCoopers LLP), where she began her career. In addition to the other current public company directorships listed above, Ms. Mora has served as a director of the Center for Internet Security (CIS), a nonprofit organization focused on strengthening cybersecurity across public and private sectors, since July 2025. Ms. Mora also served as a director of NUBURU, Inc. from 2023 to 2025, a member of the Advisory Board of The Association of LGBTQ+ Corporate Directors from 2022 to 2024, and a director of Everest Consolidator Acquisition Corporation from 2021 to 2024. Ms. Mora is a Certified Public Accountant and holds a B.A. in Political Science from the University of California, Berkeley and an M.B.A. from the Simmons College Graduate School of Management. | | Key Qualifications as Determined by our Board of Directors | | • Financial and accounting expert who served as the CFO of two major organizations, Draper Labs and Harvard University • Seasoned director with substantial experience navigating a range of public company corporate governance and regulatory issues • Critical insights into cybersecurity matters through prior oversight of IT at Draper Labs, a leader in cybersecurity threat detection, and board service with CIS |

  30. DIRECTOR COMPENSATION

    DIRECTOR COMPENSATION

  31. Director Compensation Table for 2025

    Director Compensation Table for 2025 The following table summarizes compensation earned by or paid to non-employee directors in 2025. Dr. Lee is excluded from the table because he is an executive officer and his compensation is set forth in the Executive Compensation section below, under the heading “Executive Compensation Tables — Summary Compensation Table for 2025.”

  32. Director Compensation Table for 2025

    | Name | Fees Earned or Paid in Cash ($) | Stock Awards ($)(1) | All Other Compensation ($) | Total ($) | | Rajeev Batra | $112,500 | $223,959 | - | $336,459 | | Peter J. Cannone III | $100,500(2) | $223,959 | - | $324,459 | | Gerald G. Colella | $193,000(2) | $223,959 | $26,120(3) | $443,079 | | Joseph B. Donahue | $105,280(2) | $223,959 | - | $329,239 | | Wissam G. Jabre | $100,500(2) | $223,959 | - | $324,459 | | Jacqueline F. Moloney | $140,000 | $223,959 | - | $363,959 | | Elizabeth A. Mora | $120,000 | $223,959 | - | $343,959 | | Michelle M. Warner(4) | $36,544(2) | - | - | $36,544 |

  33. Director Compensation Table for 2025

    (1) Represents the aggregate grant date fair value for each RSU granted during the year, calculated in accordance with Financial Accounting Standards Board Accounting Standards Codification 718, or ASC 718. The grant date fair value of the RSU awards was calculated based on the closing price of our Common Stock on the grant date reduced by the present value of dividends expected to be paid on our Common Stock prior to vesting. The outstanding stock awards held as of December 31, 2025 by each of the non-employee directors consisted of 2,479 RSUs. (2) Includes consideration for services on a special committee of the Board of Directors for mergers and acquisitions, which compensation consisted of a flat fee of $3,000 for up to five meetings and $1,000 per meeting thereafter up to a maximum of $10,000. In connection with their service on this special committee, Mr. Cannone, Mr. Colella, Mr. Donahue, Mr. Jabre, and Ms. Warner each received $3,000. (3) In connection with his retirement as CEO in January 2020, Mr. Colella receives retiree medical benefits for life for himself and his spouse. In addition, Mr. Colella is reimbursed for certain out-of-pocket health care costs capped at $4,500 annually. The net present value of these benefits was $503,823 as of December 31, 2025 and we paid $26,120 for these benefits in 2025. Mr. Colella receives no other retirement benefits. Ms. Warner served as a director until May 2025.

  34. Director Compensation Table for 2025

    | MKS INC. | 2026 PROXY STATEMENT | 45 |

  35. Executive Summary

    2025 Compensation Outcomes Our executive compensation program is designed to reward our Named Executive Officers for performance and to align their interests with those of our shareholders. As a result of our financial performance in 2025, our Named Executive Officers received 135% of their target variable cash compensation under our Management Incentive Plan, which was measured against two financial metrics – non-GAAP operating income and adjusted net debt – and 128% of the portion of their target performance-based equity compensation measured against Adjusted EBITDA, which vests in equal annual installments over three years beginning in February 2026 (each financial metric as further described under “Elements of Compensation” below). We believe these financial metrics are important to our shareholders because each of non-GAAP operating income and Adjusted EBITDA is an indicator of how well we manage the operations and profitability of our Company and adjusted net debt is an indicator of how well we manage our significant debt. The alignment of our financial performance goals with our incentive payout opportunities for 2025 is evidenced by the fact that our Management Incentive Plan and our performance-based equity awards subject to Adjusted EBITDA each paid out above target achievement in a year where we experienced double-digit revenue growth in our two key end markets – Semiconductor and Electronics & Packaging. Semiconductor market net revenues increased 13% over 2024 and Electronics & Packaging market net revenues increased 20% over 2024, underscoring our ability to execute on our strategy and capitalize on industry trends to deliver sustainable growth for our shareholders. Consideration of 2025 Advisory Vote on Executive Compensation At our 2025 Annual Meeting, held on May 12, 2025, we submitted to our shareholders an advisory vote on executive compensation. Although annual advisory say-on-pay votes are non-binding, our Compensation Committee considers the outcome of this vote each year when making compensation decisions for our Named Executive Officers. At the 2025 Annual Meeting, our shareholders overwhelmingly approved our executive compensation, with approximately 94% of the votes cast voting in favor of the say-on-pay proposal. The results of the say-on-pay vote indicate strong shareholder support of our compensation and pay decisions made in relation to our performance. In addition to considering the say-on-pay vote, the Compensation Committee reviews evolving best practices, market compensation information, changing regulatory requirements, and the broader business environment when evaluating our executive compensation program. Following this review, the Compensation Committee approved a return to the Company’s historical incentive compensation framework for 2025, under which achieving plan-of-record performance for both the annual cash incentive program and Adjusted EBITDA for the long-term equity incentive compensation program results in a 100% payout opportunity. This approach is consistent with the Company’s pre-2024 design. As previously disclosed, the Compensation Committee adopted a modified framework for 2024 – providing a 25% payout for plan-of-record performance – to reflect the muted business environment and increased focus on cost-reduction. Reinstating the historical framework in 2025 aligns the Company’s incentive compensation programs with prevailing market practices and supports the objectives of attracting, retaining and motivating executives to drive long-term value creation. See “Elements of Compensation — Annual Cash Incentive Compensation” and “Elements of Compensation — Long-Term Equity Incentive Compensation” below for more information about these changes.

  36. What We Do Not Do

    The following charts show the components of total target compensation on a percentage basis for our Chief Executive Officer and our other Named Executive Officers as a group for 2025. In May 2024, the Compensation Committee reviewed the peer companies to be used to determine 2025 executive compensation, which at that time consisted of 17 U.S. publicly traded companies that had been primarily selected based on similar industry and size. In determining whether these peer companies should continue to be included in the peer group, the Compensation Committee considered whether these peer companies had (i) a revenue range relative to our projected 2024 revenue between approximately 0.5 to 2.5 times, (ii) a market capitalization range relative to our average market capitalization for the twelve months ended December 31, 2023 between approximately 0.3 and 3.0 times, and (iii) an employee headcount relative to our employee headcount as of December 31, 2023 between approximately 0.5 to 3.0 times. The Compensation Committee also considered secondary factors, including whether a company is identified as a peer by proxy advisory firms or other companies, other performance considerations, and whether a company is a competitor for talent. The Compensation Committee elected to remove National Instruments Corporation, due to its acquisition by Emerson Electric Co. in October 2023, remove KLA Corporation, due to its significantly larger size, and add Waters Corporation, based on its industry classification, revenue, and executive compensation practices relative to the peer group. As a result, publicly available compensation data from the following 16 peer companies was used in determining executive compensation for 2025:

  37. What We Do Not Do

    In certain instances where robust peer group benchmark data was not available, our Compensation Committee utilized size and industry-appropriate broad survey data from the Radford McLagan Compensation Database.

  38. Elements of Compensation

    Annual Cash Incentive Compensation For 2025, the annual cash incentive program was based on two financial metrics: non-GAAP operating income, defined as our GAAP operating income excluding any charges or income not related to our operating performance and adjusted net debt, defined as our gross debt, less cash and short-term investments, adjusted for the impact of foreign currency changes and certain items that our Compensation Committee considers to be outside the ordinary course of operations. The Compensation Committee believes that non-GAAP operating income serves as a barometer of how well we manage the operations and profitability of the Company, and that adjusted net debt reinforces the importance of generating strong cash performance to reduce our debt, including by reducing inventory, improving the timeliness of accounts receivable, and achieving favorable accounts payable and continuous cost savings. For 2025, (i) non-GAAP operating income was weighted at 70% of each Named Executive Officer’s Target Bonus Amount (as defined below), and (ii) adjusted net debt was weighted at 30% of each Named Executive Officer’s Target Bonus Amount. In 2024, due to the muted business environment and increased focus on cost reduction, the Compensation Committee modified the payout curves for non-GAAP operating income and adjusted net debt so that achieving plan-of-record performance resulted in a 25% payout of a Named Executive Officer’s Target Bonus Amount for each metric, with a 100% payout requiring stretch-level performance. For 2025, to better align with market practice, the Compensation Committee reinstated the historical annual cash incentive payout curves used prior to 2024, under which plan-of-record performance corresponded to a 100% payout opportunity of the Target Bonus Amount for each metric.

  39. Elements of Compensation

    Under the Management Incentive Plan, each Named Executive Officer was eligible to receive a performance bonus based on a specified percentage of base salary earned during the 2025 calendar year. Any performance bonus under the Management Incentive Plan would be capped such that payout would not exceed an amount equal to 200% of the Named Executive Officer’s Target Bonus Amount. In 2025, payouts under the Management Incentive Plan were determined by multiplying each Named Executive Officer’s “Target Bonus Amount” by the Company’s percentage achievement of non-GAAP operating income and adjusted net debt, as described below. Target Bonus Amount consists of each Named Executive Officer’s base salary earned in 2025, multiplied by his or her “Target Bonus Percentage,” as determined by our Compensation Committee. If a Named Executive Officer’s base salary and/or Target Bonus Percentage changed during 2025, the Named Executive Officer’s Target Bonus Amount was pro-rated based on the number of days in 2025 that the Named Executive Officer received such base salary and/or Target Bonus Percentage. When our Compensation Committee met in February 2025, it elected to maintain the existing Target Bonus Percentage for Dr. Lee and increase the Target Bonus Percentages for Ms. Burke, Mr. Henry, and Mr. Schreiner by 5% to better align their bonus opportunities with the market. As previously discussed, Mr. Mayampurath’s 2025 Target Bonus Percentage was determined in connection with his October 2024 appointment and was not reviewed as part of the Compensation Committee’s annual review of executive compensation in February 2025. Listed below is the Target Bonus Percentage for each Named Executive Officer in 2024 and 2025.

  40. Elements of Compensation

    | Named Executive Officer | 2024 Target Bonus Percentage | 2025 Target Bonus Percentage | | John T.C. Lee | 125% | 125% | | Ramakumar Mayampurath | N/A | 85% | | Kathleen F. Burke | 70% | 75% | | David P. Henry | 65% | 70% | | James A. Schreiner | 65% | 70% |

  41. Elements of Compensation

    For 2025, our Compensation Committee set plan-of-record achievement for non-GAAP operating income at an amount that was lower than actual and target achievement in 2024. In setting these targets, the Compensation Committee considered management’s outlook at the time and established targets it believed were appropriately rigorous and reflective of anticipated operating conditions, including expectations for moderated demand in 2025 and cyclical softness in our end markets. Our Compensation Committee set plan-of-record achievement for adjusted net debt at an amount that would require a greater reduction in net debt than the Company had targeted or achieved in 2024, reflecting management’s focus on driving strong cash performance and debt reduction. The successful alignment of our financial performance goals with our incentive payout opportunities for 2025 is evidenced by the fact that our Management Incentive Plan paid out at 135% achievement in a year where we experienced double-digit revenue growth in our two key end markets – Semiconductor and Electronics & Packaging. Semiconductor market net revenues increased 13% over 2024 and Electronics & Packaging market net revenues increased 20% over 2024, underscoring our ability to execute on our strategy and capitalize on industry trends to deliver sustainable growth for our shareholders. Non-GAAP Operating Income Metric (70% Weighting): In 2025, Named Executive Officers were eligible to receive the following percentage of their Target Bonus Amount tied to non-GAAP operating income under the Management Incentive Plan, with proportional payments for achievement between the Threshold Bonus Amount and the Maximum Bonus Amount.

  42. Elements of Compensation

    | Non-GAAP Operating Income (for the year ended December 31, 2025) | % of Target Bonus Amount | | <$450.3 million | 0% | | $450.3 million (Threshold Bonus Amount) | 50% | | $750.5 million (Target Bonus Amount) | 100% | | ≥$900.7 million (Maximum Bonus Amount) | 200% |

  43. Elements of Compensation

    Non-GAAP operating income was $814 million for 2025. As a result, Named Executive Officers were eligible to receive 142% of their Target Bonus Amounts under this formula, or 100% when weighted at 70% of their overall cash bonus. For a full reconciliation of 2025 operating income to 2025 non-GAAP operating income, see Appendix B to this proxy statement. Adjusted Net Debt Metric (30% Weighting): In 2025, Named Executive Officers were eligible to receive the following percentage of their Target Bonus Amount tied to adjusted net debt under the Management Incentive Plan, with proportional payments for achievement between the Threshold Bonus Amount and the Maximum Bonus Amount.

  44. Elements of Compensation

    | Adjusted Net Debt (as of December 31, 2025) | % of Target Bonus Amount | | >$3.56 billion | 0% | | $3.56 billion (Threshold Bonus Amount) | 50% | | $3.31 billion (Target Bonus Amount) | 100% | | ≤$3.21 billion (Maximum Bonus Amount) | 200% |

  45. Elements of Compensation

    | Non-GAAP Operating Income % of Target Bonus Amount (Weighted at 70%) | Adjusted Net Debt % of Target Bonus Amount (Weighted at 30%) | Overall % of Target Bonus Amount | | 100% | 35% | 135% |

  46. Elements of Compensation

    | Named Executive Officer | Cash Payout | Payment as a Percentage of Target Bonus Amount | | John T.C. Lee | $1,751,533 | 135% | | Ramakumar Mayampurath | $717,188 | 135% | | Kathleen F. Burke | $540,862 | 135% | | David P. Henry | $489,330 | 135% | | James A. Schreiner | $503,758 | 135% |

  47. Elements of Compensation

    Long-Term Equity Incentive Compensation When our Compensation Committee set 2025 annual executive compensation in February 2025, it awarded the following time-based and performance-based RSUs to our Named Executive Officers. The performance-based RSUs subject to Adjusted EBITDA, which account for 70% of our Named Executive Officers’ target performance-based RSUs, are subject to a one-year performance metric, and the performance-based RSUs subject to relative total shareholder return, or rTSR, which account for 30% of our Named Executive Officers’ target performance-based RSUs, are subject to a three-year performance metric, each as described below. The performance-based RSUs subject to Adjusted EBITDA vest in three equal annual installments from the original date of grant and the performance-based RSUs subject to rTSR vest in full on or about the third anniversary of the original date of grant, in each case subject to achievement of the respective performance metric. The time-based RSUs vest in three equal annual installments from the original date of grant. Mr. Mayampurath’s time-based and performance-based RSUs were determined in connection with his

  48. Elements of Compensation

    | | Performance-Based RSUs subject to Adjusted EBITDA(1) | | Performance-Based RSUs subject to rTSR(1) | | Time-Based RSUs(1) | | | Named Executive Officer | Grant Date Value | Number | Grant Date Value | Number | Grant Date Value | Number | | John T.C. Lee | $4,200,000 | 39,822 | $1,800,000 | 17,066 | $4,000,000 | 37,925 | | Ramakumar Mayampurath | $731,500 | 6,936 | $313,500 | 2,972 | $855,000 | 8,107 | | Kathleen F. Burke | $577,500 | 5,475 | $247,500 | 2,347 | $825,000 | 7,822 | | David P. Henry | $455,000 | 4,314 | $195,000 | 1,849 | $650,000 | 6,163 | | James A. Schreiner | $332,500 | 3,153 | $142,500 | 1,351 | $475,000 | 4,504 |

  49. Elements of Compensation

    (1) Grant date value of performance-based RSUs and corresponding number of performance-based RSUs assuming 100% achievement, with achievement capped at 200%. Grant date values differ from the amounts shown in the “Stock Awards” column of the Summary Compensation Table, which represent grant date fair values calculated in accordance with ASC 718. In May 2025, in connection with Mr. Schreiner’s appointment as Executive Vice President and Chief Operating Officer, effective August 1, 2025, the Compensation Committee approved an additional (i) time-based RSU award with a grant date fair value of $125,000, (ii) performance-based RSU award tied to Adjusted EBITDA for the year ended December 31, 2025 with a grant date value of $87,500 ($175,000 at maximum achievement) and (iii) performance-based RSU award tied to rTSR for the three-year period ending December 31, 2027 with a grant date fair value of $37,500 ($75,000 at maximum achievement).

  50. Elements of Compensation

    | | Additional Performance-Based RSUs subject to Adjusted EBITDA(1) | | Additional Performance-Based RSUs subject to rTSR(1) | | Additional Time-Based RSUs(1) | | | Named Executive Officer | Grant Date Value | Number | Grant Date Value | Number | Grant Date Value | Number | | James A. Schreiner | $87,500 | 931 | $37,500 | 399 | $125,000 | 1,330 |

  51. Elements of Compensation

    (1) Grant date value of performance-based RSUs and corresponding number of performance-based RSUs assuming 100% achievement, with achievement capped at 200%. Grant date values differ from the amounts shown in the “Stock Awards” column of the Summary Compensation Table, which represent grant date fair values calculated in accordance with ASC 718. Listed below is the aggregate grant date value of the RSUs for each Named Executive Officer in 2024 and 2025.

  52. Elements of Compensation

    | | Grant Date Value of Performance- Based RSUs(1) | | Grant Date Value of Time-Based RSUs(1) | | Total Grant Date Value(1) | | | Named Executive Officer | 2024 | 2025 | 2024 | 2025 | 2024 | 2025 | | John T.C. Lee | $4,200,000 | $6,000,000 | $2,800,000 | $4,000,000 | $7,000,000 | $10,000,000 | | Ramakumar Mayampurath | $N/A | $1,045,000 | $1,750,000(2) | $855,000 | $1,750,000(2) | $1,900,000 | | Kathleen F. Burke | $612,500 | $825,000 | $612,500 | $825,000 | $1,225,000 | $1,650,000 | | David P. Henry | $475,000 | $650,000 | $475,000 | $650,000 | $950,000 | $1,300,000 | | James A. Schreiner | $450,000 | $600,000 | $450,000 | $600,000 | $900,000 | $1,200,000 |

  53. Elements of Compensation

    (1) Grant date value of performance-based RSUs assuming 100% achievement, with achievement capped at 200%. Grant date values differ from the amounts shown in the “Stock Awards” column of the Summary Compensation Table, which represent grant date fair values calculated in accordance with ASC 718. Mr. Mayampurath received a one-time sign-on equity award in the form of time-based RSUs in 2024 in connection with his appointment in October 2024.

  54. Elements of Compensation

    With respect to performance-based RSUs, our goal is to select Company financial metrics that best align with our Company objectives. Since 2024, performance-based RSUs have been subject to two performance metrics: Adjusted EBITDA and rTSR. We believe Adjusted EBITDA provides a clear indication of how effectively we manage the operations of our Company, while continuing to recognize the cyclical nature and volatility of the markets we serve, as well as to drive continued improvement in our Company’s operating model independent of revenue levels. Further, we believe rTSR strengthens long-term alignment between executive and shareholder interests and elevates the performance orientation of our executive compensation program. In February 2025, Dr. Lee, Mr. Mayampurath, Ms. Burke, Mr. Henry, and Mr. Schreiner received two performance-based awards, one of which was subject to Adjusted EBITDA and accounted for 70% of his or her target performance-based RSUs and the other of which was subject to rTSR and accounted for 30% of his or her target performance-based RSUs. As discussed above, in August 2025, Mr. Schreiner received two additional performance-based awards subject to the same performance metrics and weightings as the performance-based awards he received in February 2025. In 2024, due to the muted business environment and increased focus on cost reduction, the Compensation Committee modified the payout curve for Adjusted EBITDA such that achievement of plan-of-record Adjusted EBITDA resulted in 25% achievement of a Named Executive Officer’s performance-based RSUs subject to Adjusted EBITDA for 2024. For a Named Executive Officer to receive 100% achievement of his or her performance-based RSUs subject to Adjusted EBITDA in 2024, the Company had to achieve a stretch target above plan-of-record Adjusted EBITDA. For 2025, to better align with market practice, our Compensation Committee reinstated the historical design used prior to 2024 for performance-based RSUs subject to Adjusted EBITDA, under which plan-of-record performance corresponds to 100% achievement of a Named Executive Officer’s performance-based RSUs. In addition, our Compensation Committee decided to measure Adjusted EBITDA independent of revenue levels for greater alignment with the non-GAAP operating income metric under the Management Incentive Plan. We choose to measure Adjusted EBITDA over a one-year performance period because of the cyclical nature and volatility of our markets, making it challenging to set multi-year performance targets, as evidenced by continued cyclical challenges in our end markets. To ensure our executive officers are focused on our Company’s long-term performance, the performance-based RSUs subject to Adjusted EBITDA vest in equal annual installments over three years from the original date of grant, subject to achievement of the performance metric. In addition, we choose to measure rTSR over a three-year performance period to further ensure executives are aligned with long-term shareholder interests. 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 stock options, which have a relatively high accounting cost as compared to their potential value to the executive officer, and restricted stock, which gives the executive officer voting and dividend rights prior to full vesting. Also, because RSUs are worth more than stock options on the date of grant, we are able to grant fewer RSUs as compared to stock options, resulting in less potential dilution to shareholders’ holdings. Consistent with management expectations that informed the 2025 non-GAAP operating income target under the Management Incentive Plan, our Compensation Committee set 2025 plan-of-record achievement for Adjusted EBITDA at an amount that was lower than actual and target achievement in 2024, reflecting the Company’s expectations for moderated demand in 2025 and cyclical softness in our end markets. Our Named Executive Officers were eligible to receive the following percentage of their target performance-based RSUs subject to Adjusted EBITDA, with proportional payments for achievement between the Threshold Amount and the Maximum Amount.

  55. Elements of Compensation

    If the percentage achievement for performance-based RSUs subject to Adjusted EBITDA was greater than 25% of the percentage achievement for the non-GAAP operating income metric of our annual cash incentive program, then our Compensation Committee could apply negative discretion with respect to the performance-based RSUs subject to Adjusted EBITDA up to an amount equal to the percentage achievement for the non-GAAP operating income metric. Our Compensation Committee believes the application of negative discretion under these circumstances helps foster appropriate alignment between pay and performance. In 2025, because Adjusted EBITDA was $966 million, our Named Executive Officers received 128% of their target performance-based RSUs subject to Adjusted EBITDA, in a year where we experienced double-digit revenue growth in our two key end markets – Semiconductor and Electronics & Packaging. Semiconductor market net revenues increased 13% over 2024 and Electronics & Packaging market net revenues increased 20% over 2024, underscoring our ability to execute on our strategy and capitalize on industry trends to deliver sustainable growth for our shareholders. For a full reconciliation of 2025 net income to 2025 Adjusted EBITDA, see Appendix B to this proxy statement. The performance-based RSUs subject to rTSR that were granted to our Named Executive Officers in February 2025 will be measured over a three-year performance period from January 1, 2025 to December 31, 2027. rTSR for this performance period will be measured by comparing the 20-day trading day average of each of MKS and the S&P 1500 Composite Electronic Equipment, Instruments & Components Index at the beginning of the performance period against the respective 20-day trading day average at the end of the performance period. Our Named Executive Officers will be eligible to receive the following percentage achievement of their performance-based RSUs subject to rTSR (subject to certain caps discussed below), with proportional payments for achievement between the Threshold Amount and the Maximum Amount.

  56. Elements of Compensation

    Percentage achievement of the performance-based RSUs subject to rTSR is subject to two caps. First, if the Company has a negative absolute rTSR at the end of the performance period but is above the 50th percentile, eligible Named Executive Officers will receive no more than 50% of their target performance-based RSUs subject to rTSR. Second, the total value of the award at vest shall not exceed 8x the value of the award on the grant date. Additional Information Regarding Equity Awards 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. We may also make equity-based grants to a Named Executed Officer in connection with a promotion or other change in position. As discussed above, in connection with Mr. Schreiner’s appointment as Executive Vice President and Chief Operating Officer, the Compensation Committee approved additional equity awards for Mr. Schreiner. 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 awards may also be made during the year to provide an incentive to achieve a specific goal or to reward a significant achievement or for other reasons that the Compensation Committee determines. Perquisites We do not offer perquisites. Our Compensation Committee believes this practice simplifies and more consistently aligns our compensation and benefits offerings for Named Executive Officers with other employees, while placing greater focus on performance-based compensation.

  57. Severance and Change-in-Control Provisions

    Severance and Change-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 and subject to his or her entry into a release of claims. In exchange for these payments and benefits, each of these officers has agreed to be 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 with time-based vesting generally 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 a change-in-control event. RSU agreements with our Named Executive Officers with performance-based vesting based on Adjusted EBITDA provide for acceleration of vesting at target-level achievement in the event the executive’s employment is terminated without cause or the executive resigns for good reason within 24 months after a change-in-control event. RSU agreements with our Named Executive Officers with performance-based vesting based on rTSR provide that the performance period for such shares shall end on the day prior to the closing date of a change in control, with the number of shares, if any, that would have vested on such date, as determined in accordance with the terms of such agreements, converting into time-based vesting RSUs subject to 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 a change-in-control event. The severance and change-in-control provisions are designed to be competitive in the marketplace, to provide security for each of 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 our Named Executive Officers to stay with us through such a change-in-control event. These provisions are also intended to protect us from competitive harm by compensating our Named Executive Officers for agreeing to substantial non-compete provisions after employment termination. See “Executive Compensation Tables — Potential Payments Upon Termination or Change-in-Control” for more information about these agreements.

  58. Compensation Consultant

    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: • to provide the Compensation Committee with occasional consultation regarding compensation strategies and programs; • to review our peer group to determine the appropriateness of its composition; • to conduct formal competitive compensation analysis for the Compensation Committee regarding our directors and each executive officer, on a position-by-position basis, in comparison to similarly situated executive officers in our peer group using benchmarking data; • to assess the rigor of proposed performance goals on the basis of a probability analysis, a year-over-year growth analysis and a historical payout versus our peer group analysis; and to assist the Compensation Committee with conducting a risk assessment of all of the Company’s compensation policies and practices.

  59. Compensation Consultant

    | MKS INC. | 2026 PROXY STATEMENT | 64 |

  60. Compensation Consultant

    Since May 2019, the Compensation Committee has engaged Pearl Meyer as its compensation consultant. The Compensation Committee has determined that the engagement of Pearl Meyer as a compensation consultant does not raise any conflicts of interest with MKS.

  61. Governance Policies

    Governance Policies Stock Ownership Guidelines Our Stock Ownership Guidelines, which apply to members of the Board of Directors, the Chief Executive Officer, and our other Named Executive Officers in their capacities as Executive Vice Presidents, provide for the following ownership goals: • Non-employee members of the Board of Directors shall own at least the number of shares of our Common Stock equal in value to five times the annual retainer for Board service (exclusive of any compensation for committee service, meeting fees, leadership roles, and the like). • The Chief Executive Officer shall own at least the number of shares of our Common Stock with a value equal to five times his or her annual base salary (excluding any bonus, award, or special compensation). • Our other Named Executive Officers, in their capacities as Executive Vice Presidents, shall own at least the number of shares of our Common Stock with a value equal to three times his or her annual base salary (excluding any bonus, award, or special compensation). Share ownership is measured as of December 31 of each year. Our Stock Ownership Guidelines count shares of our Common Stock and restricted stock units toward share ownership, except that restricted stock units subject to performance conditions are not counted. The Stock Ownership Guidelines provide for a phase-in period over five years to achieve compliance. If an individual has not attained his or her ownership goal, the individual may not sell any shares of our Common Stock acquired through his or her employment or directorship (except sales of shares of our Common Stock to pay taxes on vesting) until the next measurement date where the individual is in compliance with his or her ownership goal. As of December 31, 2025, our directors, CEO, and other Named Executive Officers were all in compliance with our Stock Ownership Guidelines or within the phase-in period.

  62. Policies and Practices Related to the Grant of Equity Awards

    Policies and Practices Related to the Grant of Equity Awards We grant equity awards, including restricted stock units, to our non-employee directors, officers, and certain of our employees on an annual basis. We may also grant equity awards to individuals upon hire or promotion or for retention purposes. We currently do not grant stock options, stock appreciation rights, or similar option-like instruments, and only grant restricted stock units. During the last fiscal year, neither our Board nor our Compensation Committee took material nonpublic information into account when determining the timing or terms of equity awards, nor did the Company time the disclosure of material nonpublic information for the purpose of affecting the value of executive compensation.

  63. Summary Compensation Table for 2025

    Summary Compensation Table for 2025 The following table sets forth the aggregate amounts of compensation earned by our Named Executive Officers in the years ended December 31, 2025, 2024, and 2023.

  64. Summary Compensation Table for 2025

    | Name and Principal Position | Year | Salary ($) | Bonus ($) | Stock Awards ($)(1) | Non-Equity Incentive Plan Compensation ($)(2) | All Other Compensation ($)(3) | Total ($) | | John T.C. Lee, | | | | | | | | | President and CEO (principal executive officer) | 2025 | $1,037,945 | $- | $10,133,327 | $1,751,533 | $39,135 | $12,961,940 | | | 2024 | $970,492 | $- | $7,388,552 | $363,935 | $37,146 | $8,760,125 | | | 2023 | $950,000 | $- | $5,900,090 | $1,021,250 | $35,288 | $7,906,628 | | Ramakumar Mayampurath, | | | | | | | | | EVP and CFO (principal financial officer)(4) | 2025 | $625,000 | $- | $1,920,714 | $717,188 | $30,416 | $3,293,318 | | | 2024 | $134,906 | $1,000,000(5) | $1,721,962 | $- | $60,601 | $2,917,469 | | Kathleen F. Burke, | | | | | | | | | EVP, General Counsel, and Secretary | 2025 | $542,526 | $- | $1,663,978 | $540,862 | $38,255 | $2,785,621 | | | 2024 | $510,148 | $- | $1,278,911 | $107,131 | $36,264 | $1,932,454 | | | 2023 | $504,000 | $- | $1,106,267 | $303,408 | $35,288 | $1,948,963 | | David P. Henry, | | | | | | | | | EVP, Global Strategic Marketing, and General Manager, MSD | 2025 | $525,800 | $- | $1,311,013 | $489,330 | $42,710 | $2,368,853 | | | 2024 | $455,738 | $- | $991,808 | $88,869 | $36,498 | $1,572,913 | | | 2023 | $450,000 | $- | $737,511 | $251,550 | $35,403 | $1,474,464 | | James A. Schreiner, | | | | | | | | | EVP and COO | 2025 | $541,447 | $- | $1,201,681 | $503,758 | $623,949 | $2,870,835 | | | 2024 | $477,900 | $- | $1,781,290 | $93,191 | $320,244 | $2,672,625 | | | 2023 | $465,718 | $- | $786,679 | $260,337 | $494,827 | $2,007,561 |

  65. Summary Compensation Table for 2025

    (1) Represents the aggregate grant date fair value for each RSU granted to the Named Executive Officer during the covered year, calculated in accordance with ASC 718. The grant date fair value of time-based RSU awards was calculated based on the closing price of our Common Stock on the grant date reduced by the present value of dividends expected to be paid on our Common Stock prior to vesting. The grant date fair value of performance-based RSU awards subject to Adjusted EBITDA was calculated at target achievement and based on the closing price of our Common Stock on the grant date reduced by the present value of dividends expected to be paid on our Common Stock prior to vesting. The grant date fair value of performance-based RSU awards subject to rTSR granted to our Named Executive Officers in February 2025 and to Mr. Schreiner in August 2025 was calculated using the Monte Carlo simulation model, which required the use of the following assumptions:

  66. Summary Compensation Table for 2025

    | Grant Date | Expected Stock Price Volatility for MKS | Expected Term (Years) | Risk-Free Interest Rate | Expected Dividend Yield | | February 18, 2025 | 46.83% | 2.86 | 4.24% | 0.79% | | August 4, 2025 | 50.47% | 2.41 | 3.61% | 0.94% |

  67. Summary Compensation Table for 2025

    | MKS INC. | 2026 PROXY STATEMENT | 68 |

  68. Summary Compensation Table for 2025

    The amounts under the “Stock Awards” column do not reflect the amount of compensation actually received by the Named Executive Officers during the fiscal year. Except with respect to Mr. Mayampurath and Mr. Schreiner in 2024, at least fifty percent of the values listed under “Stock Awards” represent performance-based RSUs, which are valued at the grant date based upon the probable outcome of the performance metrics. The following table sets forth the maximum value of the RSUs, assuming the highest level of performance is achieved for the performance-based portion of the RSUs, if applicable:

  69. Summary Compensation Table for 2025

    | Named Executive Officer | 2025 Maximum | 2024 Maximum | 2023 Maximum | | Dr. Lee | $15,746,658 | $11,048,979 | $9,440,144 | | Mr. Mayampurath | $2,898,369 | $1,721,962 | $N/A | | Ms. Burke | $2,435,811 | $1,812,723 | $1,659,400 | | Mr. Henry | $1,919,124 | $1,405,785 | $1,106,267 | | Mr. Schreiner | $1,770,734 | $2,173,478 | $1,180,018 |

  70. Summary Compensation Table for 2025

    On November 15, 2024, in connection with his hiring, Mr. Mayampurath was granted a one-time sign-on equity award with a grant date value of $1,750,000 in the form of time-based RSUs, which vests in two equal annual installments beginning in November 2025. He did not receive an annual stock award in 2024. In addition to his annual stock award for 2024, on May 15, 2024, Mr. Schreiner received an expatriate service equity award with a grant date value of $850,000 in the form of time-based RSUs, 60% of which vested on August 17, 2024 and 40% of which vested on August 18, 2025. This award was made pursuant to an amendment to Mr. Schreiner’s employment agreement with the Company to extend his expatriate service in Berlin, Germany for a third year. This award replaced an expatriate service cash bonus of $500,000 that was due to be paid to Mr. Schreiner on or shortly after August 17, 2024. (2) Each Named Executive Officer’s annual cash performance bonus for 2025, 2024, and 2023 was calculated based on a specified target percentage of his or her eligible earnings for the relevant plan year. For 2025 and 2023, the threshold bonus payout was 50% of this individual target bonus percentage and the maximum payout was 200% of this individual target bonus percentage, with proportional payouts for performance between these levels. For 2024, the threshold bonus payout was 0% of this individual target bonus percentage and the maximum payout was 200% of this individual target bonus percentage, with proportional payouts for performance between these levels. Bonus payments in 2025 were based on the achievement of two financial metrics: (i) non-GAAP operating income (defined as GAAP operating income excluding any charges or income not related to the operating performance of the Company) and (ii) adjusted net debt (defined as gross debt, less cash and short-term investments, adjusted for the impact of foreign currency changes and certain items that our Compensation Committee considers to be outside the ordinary course of operations) for 2025. Bonus payments in 2024 were based on the achievement of two financial metrics: (i) non-GAAP operating income (defined as GAAP operating income excluding any charges or income not related to the operating performance of the Company), excluding the non-executive bonus adjustment, which represented approximately $13 million associated with our Compensation Committee’s decision to increase the payout of non-executive cash bonuses to 50% of target in 2024, and which we refer to as the Non-Executive Bonus Adjustment, and (ii) adjusted net debt (defined as gross debt, less cash and short-term investments, adjusted for the impact of foreign currency changes and certain items that our Compensation Committee considers to be outside the ordinary course of operations) for 2024. Bonus payments in 2023 were based on the achievement of non-GAAP operating income (defined as GAAP operating income after bonus and excluding any charges or income not related to the operating performance of the Company) for 2023. The individual target bonus percentage (excluding the impact of prorated adjustments due to mid-year changes in target bonus percentage) and the actual bonus achieved for each of the Named Executive Officers were as follows:

  71. Summary Compensation Table for 2025

    | | 2025 | | 2024 | | 2023 | | | Named Executive Officer | Individual Target Bonus % | Annual Bonus Plan Achievement | Individual Target Bonus % | Annual Bonus Plan Achievement | Individual Target Bonus % | Annual Bonus Plan Achievement | | Dr. Lee | 125% | 135% | 125% | 30% | 125% | 86% | | Mr. Mayampurath | 85% | 135% | N/A | N/A | N/A | N/A | | Ms. Burke | 75% | 135% | 70% | 30% | 70% | 86% | | Mr. Henry | 70% | 135% | 65% | 30% | 65% | 86% | | Mr. Schreiner | 70% | 135% | 65% | 30% | 65% | 86% |

  72. Summary Compensation Table for 2025

    | MKS INC. | 2026 PROXY STATEMENT | 69 |

  73. Summary Compensation Table for 2025

    Our Compensation Committee elected to discontinue perquisites effective December 31, 2020, with the exception that Mr. Schreiner and Seth Bagshaw, our former Executive Vice President, Chief Financial Officer, and Treasurer, were permitted to retain their company-leased cars until the expiration of their leases in November 2023 and May 2023, respectively, to avoid lease cancellation costs. The amounts paid to our Named Executive Officers for such perquisites and the amount of all other compensation consisted of the following:

  74. Summary Compensation Table for 2025

    | Named Executive Officer | Year | Auto | Health & Disability | 401(k) Match | Global Mobility | Relocation | | Dr. Lee | 2025 | $- | $28,635 | $10,500 | $- | $- | | | 2024 | $- | $26,796 | $10,350 | $- | $- | | | 2023 | $- | $25,388 | $9,900 | $- | $- | | Mr. Mayampurath | 2025 | $- | $19,916 | $10,500 | $- | $- | | | 2024 | $- | $3,590 | $2,163 | $- | $54,848 | | | 2023 | $- | $- | $- | $- | $- | | Ms. Burke | 2025 | $- | $27,755 | $10,500 | $- | $- | | | 2024 | $- | $25,914 | $10,350 | $- | $- | | | 2023 | $- | $25,388 | $9,900 | $- | $- | | Mr. Henry | 2025 | $- | $28,010 | $10,500 | $4,200 | $- | | | 2024 | $- | $26,148 | $10,350 | $- | $- | | | 2023 | $- | $25,503 | $9,900 | $- | $- | | Mr. Schreiner | 2025 | $- | $28,039 | $10,500 | $585,410 | $- | | | 2024 | $- | $26,192 | $10,350 | $283,702 | $- | | | 2023 | $11,323 | $25,629 | $9,900 | $447,976 | $- |

  75. Summary Compensation Table for 2025

    Health & Disability benefits for 2025 included partial payment of premiums for medical, dental, vision, short-term and long-term disability, and life insurance. Global Mobility benefits for Mr. Schreiner in 2025 included benefits provided to Mr. Schreiner as a result of his expatriate service in Germany, including housing and utilities, auto, home leave, work permit assistance, local country unemployment insurance, moving expenses and tax equalization payments. The tax equalization payments for 2025, which amount to $390,489, reflect the estimated total net amount of tax equalization designed to cover taxes on Mr. Schreiner’s compensation in excess of the taxes he would have incurred in the United States, in accordance with our global mobility program. Global Mobility benefits for Mr. Henry in 2025 consisted of visa work permit fees in connection with his business travel to Germany, provided in accordance with the Company’s Global Travel Policy. (4) Mr. Mayampurath joined the Company in October 2024. Accordingly, his compensation is not included with respect to 2023. Represents a one-time sign-on cash bonus of $1,000,000, subject to repayment if Mr. Mayampurath voluntarily resigns or his employment is terminated for cause, each prior to the second anniversary of his start date.

  76. Summary Compensation Table for 2025

    | MKS INC. | 2026 PROXY STATEMENT | 70 |

  77. Grants of Plan-Based Awards in Fiscal Year 2025 Table

    Grants of Plan-Based Awards in Fiscal Year 2025 Table

  78. Grants of Plan-Based Awards in Fiscal Year 2025 Table

    | | | | Estimated Future Payouts Under Non-Equity Incentive Plan Awards(3) | | | Estimated Future Payouts Under Equity Incentive Plan Awards | | | All Other Stock Awards: Number of Shares of Stock or | Grant Date Fair Value of Stock | | Name | Grant Date(1) | Approval Date(2) | Threshold ($) | Target ($) | Maximum ($) | Threshold (#) | Target (#) | Maximum (#) | Units (#)(4) | Awards ($)(5) | | John T.C. Lee | N/A | N/A | $656,250 | $1,312,500 | $2,625,000 | | | | | | | | 2/18/25 | 2/10/25 | | | | | | | 37,925 | $3,936,664 | | | 2/18/25 (6) | 2/10/25 | | | | 19,911 | 39,822 | 79,644 | | $4,133,498 | | | 2/18/25 (7) | 2/10/25 | | | | 4,267 | 17,066 | 34,133 | | $2,063,165 | | Ramakumar Mayampurath | N/A | N/A | $265,625 | $531,250 | $1,062,500 | | | | | | | | 2/18/25 | 7/24/24 | | | | | | | 8,107 | $841,462 | | | 2/18/25 (6) | 7/24/24 | | | | 3,468 | 6,936 | 13,871 | | $719,918 | | | 2/18/25 (7) | 7/24/24 | | | | 743 | 2,972 | 5,945 | | $359,335 | | Kathleen F. Burke | N/A | N/A | $206,625 | $412,500 | $825,000 | | | | | | | | 2/18/25 | 2/10/25 | | | | | | | 7,822 | $811,937 | | | 2/18/25 (6) | 2/10/25 | | | | 2,738 | 5,475 | 10,951 | | $568,356 | | | 2/18/25 (7) | 2/10/25 | | | | 587 | 2,347 | 4,693 | | $283,685 | | David P. Henry | N/A | N/A | $201,250 | $402,500 | $805,000 | | | | | | | | 2/18/25 | 2/10/25 | | | | | | | 6,163 | $639,708 | | | 2/18/25 (6) | 2/10/25 | | | | 2,157 | 4,314 | 8,628 | | $447,796 | | | 2/18/25 (7) | 2/10/25 | | | | 462 | 1,849 | 3,698 | | $223,510 | | James A. Schreiner | N/A | N/A | $210,000 | $420,000 | $840,000 | | | | | | | | 2/18/25 | 2/10/25 | | | | | | | 4,504 | $467,479 | | | 2/18/25 (6) | 2/10/25 | | | | 1,576 | 3,153 | 6,305 | | $327,235 | | | 2/18/25 (7) | 2/10/25 | | | | 338 | 1,351 | 2,702 | | $163,334 | | | 8/4/25 | 5/12/25 | | | | | | | 1,330 | $122,766 | | | 8/4/25 (6) | 5/12/25 | | | | 465 | 931 | 1,862 | | $85,936 | | | 8/4/25 (7) | 5/12/25 | | | | 100 | 399 | 798 | | $34,931 |

  79. Grants of Plan-Based Awards in Fiscal Year 2025 Table

    (1) This column shows the date of grant for equity awards granted in 2025, all of which were made under the 2022 Stock Incentive Plan. (2) This column shows the date on which the Compensation Committee approved the grant of equity awards. (3) Represents aggregate threshold, target, and maximum payout levels under the annual cash incentive plan. The actual amount of annual cash incentive compensation earned by each Named Executive Officer is reported under the Non-Equity Incentive Plan Compensation column in the Summary Compensation Table for 2025. See Footnote 2 to the Summary Compensation Table for 2025 for details on the terms of the annual cash incentive plan. (4) The RSUs granted to Dr. Lee, Mr. Mayampurath, Ms. Burke, Mr. Henry, and Mr. Schreiner on February 18, 2025 and the RSUs granted to Mr. Schreiner on August 4, 2025 vest in equal annual installments over three years beginning in February 2026. (5) Represents the grant date fair value calculated in accordance with ASC 718. See Footnote 1 to the Summary Compensation Table for additional information. (6) These RSUs were subject to achievement of Adjusted EBITDA over a one-year performance period. These RSUs vest in equal annual installments over three years beginning in February 2026, subject to achievement of the performance metric, which was established in 2025 and determined in February 2026. These RSUs are subject to achievement of rTSR over a three-year performance period. These RSUs vest in full in February 2028, subject to achievement of the performance metric, which was established in 2025 and is expected to be determined in February 2028.

  80. Grants of Plan-Based Awards in Fiscal Year 2025 Table

    | MKS INC. | 2026 PROXY STATEMENT | 71 |

  81. Outstanding Equity Awards at 2025 Fiscal Year-End Table

    Outstanding Equity Awards at 2025 Fiscal Year-End Table

  82. Outstanding Equity Awards at 2025 Fiscal Year-End Table

    | | Stock Awards(1) | | | | | Name | Number of Shares or Units of Stock That Have Not Vested (#) | Market Value of Shares or Units of Stock That Have Not Vested(2) ($) | Equity Incentive Plan Awards: Number of Unearned Shares, Units or Other Rights That Have Not Vested (#) | Equity Incentive Plan Awards: Market or Payout Value of Unearned Shares, Units or Other Rights That Have Not Vested(2) ($) | | John T.C. Lee | 29,742(3) | $4,752,722 | 20,347(4) | $3,251,482 | | | 22,136(5) | $3,537,405 | 79,644(6) | $12,727,031 | | | 36,274(7) | $5,796,661 | 34,133(8) | $5,454,442 | | Ramakumar Mayampurath | 8,296(9) | $1,325,673 | 13,871(6) | $2,216,625 | | | 8,107(7) | $1,295,430 | 5,945(8) | $949,982 | | Kathleen F. Burke | 5,239(3) | $837,127 | 2,967(4) | $474,175 | | | 4,279(5) | $683,786 | 10,951(6) | $1,749,967 | | | 7,481(7) | $1,195,485 | 4,693(8) | $749,986 | | David P. Henry | 3,653(3) | $583,706 | 2,301(4) | $367,727 | | | 3,471(5) | $554,592 | 8,628(6) | $1,378,762 | | | 6,163(7) | $984,830 | 3,698(8) | $590,898 | | James A. Schreiner | 3,897(3) | $622,758 | 2,180(4) | $348,373 | | | 3,288(5) | $525,357 | 6,305(6) | $1,007,557 | | | 4,504(7) | $719,683 | 2,702(8) | $431,810 | | | 1,330(10) | $212,500 | 1,862(11) | $297,500 | | | | | 798(12) | $127,500 |

  83. Outstanding Equity Awards at 2025 Fiscal Year-End Table

    (1) All stock awards in the above table are RSUs. Except as otherwise noted below, all RSUs vest in three equal annual installments, with an annual vesting date of February 15th or the next business day if February 15th is not a business day. None of the Named Executive Officers had any outstanding option awards. (2) Values were calculated based on the closing price of our Common Stock on December 31, 2025 of $159.80 per share. (3) Grant date is February 15, 2023. (4) Grant date is February 15, 2024. Number of shares assumes maximum achievement of performance criteria (rTSR). These RSUs vest on February 15, 2027. (5) Grant date is February 15, 2024. (6) Grant date is February 18, 2025. Number of shares assumes maximum achievement of performance criteria (Adjusted EBITDA). (7) Grant date is February 18, 2025. (8) Grant date is February 18, 2025. Number of shares assumes maximum achievement of performance criteria (rTSR). These RSUs vest on February 15, 2028. (9) Grant date is November 15, 2024. These RSUs vest in two equal annual installments, with an annual vesting date of November 15th or the next business day if November 15th is not a business day. (10) Grant date is August 4, 2025. (11) Grant date is August 4, 2025. Number of shares assumes maximum achievement of performance criteria (Adjusted EBITDA). Grant date is August 4, 2025. Number of shares assumes maximum achievement of performance criteria (rTSR). These RSUs vest on February 15, 2028.

  84. Outstanding Equity Awards at 2025 Fiscal Year-End Table

    | MKS INC. | 2026 PROXY STATEMENT | 72 |

  85. Option Exercises and Stock Vested in Fiscal Year 2025 Table

    Option Exercises and Stock Vested in Fiscal Year 2025 Table

  86. Option Exercises and Stock Vested in Fiscal Year 2025 Table

    | | Stock Awards* | | | Name | Number of Shares Acquired on Vesting (#)(1) | Value Realized on Vesting ($)(2) | | John T.C. Lee | 63,764(3) | $6,690,602 | | Ramakumar Mayampurath | 8,295 | $1,184,028 | | Kathleen F. Burke | 12,423(3) | $1,318,989 | | David P. Henry | 8,014 | $830,775 | | James A. Schreiner | 10,982 | $1,129,376 |

  87. Option Exercises and Stock Vested in Fiscal Year 2025 Table

    (1) Reflects the number of shares vested before the surrender of shares in satisfaction of tax withholding obligations. (2) Reflects the value realized before satisfaction of tax withholding obligations. (3) Includes 2,003 shares and 777 shares that vested to cover U.S. Federal Insurance Contribution Act (FICA) tax withholding obligations for Dr. Lee and Ms. Burke, respectively, who each met early retirement criteria under the related RSU agreements in 2025. * The Named Executive Officers did not hold any options in 2025.

  88. Potential Payments Upon Termination or Change-in-Control

    Potential Payments Upon Termination or Change-in-Control This section, including the tables below, summarizes the estimated payments and other benefits that each Named Executive Officer would be eligible to receive if his or her employment had terminated on December 31, 2025, under the circumstances set forth below.

  89. John T.C. Lee

    John T.C. Lee Pursuant to the terms of Dr. Lee’s employment agreement dated as of November 18, 2019, Dr. Lee is entitled to receive a base salary and to participate in the Company’s annual cash incentive program and long-term equity incentive plan. From time to time in its sole discretion, our Compensation Committee may review and adjust Dr. Lee’s base salary, target compensation goal for the annual cash incentive program, and target award for the long-term equity incentive plan. Dr. Lee’s employment agreement provides for a term that is at-will, with termination upon death or disability or at the election of Dr. Lee or the Company. Under the employment agreement, and consistent with applicable law, on any termination of employment, Dr. Lee is entitled to: (i) any unpaid base salary through the employment end date, (ii) accrued, vested benefits under the Company’s benefit plans and programs and pursuant to any equity award agreements relating to awards under the current or any future Company equity incentive plan, (iii) any accrued but unused vacation, and (iv) any unreimbursed expenses incurred through the employment end date in accordance with the Company’s expense reimbursement policies. In the event that Dr. Lee’s employment is terminated by the Company without cause (as defined below) or is terminated by Dr. Lee for good reason (as defined below), he is entitled to: (i) continuation of base salary for 18 months, (ii) a lump sum equal to 1.5 times the annual amount of his target cash incentive compensation for which he is eligible, (iii) any cash incentive compensation earned for the calendar year preceding his termination but not yet paid, and (iv) to the extent that he elects to continue coverage, payment by the Company of premiums for medical, vision, and dental insurance coverage under COBRA for a period of 18 months, less the premium contribution paid by similarly situated employees. In the event that Dr. Lee’s employment is terminated by the Company without cause, or is terminated by Dr. Lee for good reason, within 24 months after a change-in-control (as defined in his employment agreement), he is entitled to: (i) a lump sum payment equal to three times his annual base salary, (ii) a lump sum payment equal to three times the annual amount of his target cash incentive compensation, (iii) any cash incentive compensation earned for the calendar year preceding his termination but not yet paid, (iv) a prorated portion of his then-current year’s target cash incentive compensation, and (v) to the extent that he elects to continue coverage, payment by the Company of its usual share of premiums for medical, vision, and dental insurance coverage under COBRA during the period of time Dr. Lee is entitled to elect such coverage under COBRA, and after the end of the COBRA continuation

  90. John T.C. Lee

    | MKS INC. | 2026 PROXY STATEMENT | 73 |

  91. John T.C. Lee

    period, if Dr. Lee continues to pay the premium that would be charged for COBRA coverage, he may continue such insurance coverage until the end of the 36 month period following his employment termination date on the same terms as if COBRA coverage were still in effect and the Company will continue to pay the Company’s usual share of such premiums. In the event such payments are determined to be subject to an excise tax imposed by Section 4999 of the Internal Revenue Code, such payments will be payable in full or, if applicable, reduced so that no portion of the payments is subject to the excise tax, whichever of the foregoing amounts results in receipt by Dr. Lee on an after-tax basis of the greater amount, taking into account all applicable taxes, including the penalty tax. Dr. Lee is not entitled to any gross-up payment for any such excise tax due. In the event Dr. Lee’s employment is terminated due to death or disability, he (or his estate) is entitled to: (i) any cash incentive compensation earned for the calendar year preceding his termination but not yet paid and (ii) a prorated portion of his then-current year’s target cash incentive compensation. Dr. Lee’s employment agreement contains non-competition provisions that provide that he may not, during the term of his employment and for one year after termination of employment, engage in any competitive business or activity. In addition, he may not, during the term of employment and for two years after the termination of employment: (i) solicit, hire or otherwise induce any Company employee to terminate his or her employment with the Company, (ii) solicit or hire any of our suppliers, joint ventures, research partners or customers for the purpose of competing with the Company, (iii) encourage any of such persons or entities not to enter into a business relationship with the Company or interfere with the relationship between the Company and such persons or entities, or (iv) sell to any of the Company’s customers any products of the types sold by the Company with respect to which products he had material dealings in the performance of his duties within the period two years prior to his termination. Any equity awarded to Dr. Lee under the current or any future Company equity incentive plan that is unvested as of Dr. Lee’s termination of employment date will be subject to accelerated vesting to the extent provided in the equity award agreements governing the award. Dr. Lee has entered into time-based RSU agreements; performance-based RSU agreements subject to Adjusted EBITDA, which we refer to as Adjusted EBITDA RSU agreements; and performance-based RSU agreements subject to rTSR, which we refer to as rTSR RSU agreements. In the case of the time-based RSU agreements and the Adjusted EBITDA RSU agreements, if Dr. Lee is terminated without cause or resigns with good reason within 24 months following a change-in-control (as defined in the applicable RSU agreements), the RSU agreements provide for full acceleration of vesting of all RSUs, provided, that, in the case of the Adjusted EBITDA RSU agreements, if the RSUs are still subject to performance criteria, only the target number of RSUs will vest. In the case of the rTSR RSU agreements, if the RSUs are still subject to performance criteria at the time of the change-in-control, the RSUs will be converted into time-based RSUs, which we refer to as Converted RSUs, based on actual performance, using the per share price paid to holders of our Common Stock in connection with the change-in-control as the “end price” for purposes of determining rTSR. If the acquiring entity refuses to assume the Converted RSUs, the rTSR RSU agreements provide for full acceleration of vesting of all Converted RSUs. If the acquiring entity assumes the Converted RSUs and Dr. Lee is terminated without cause or resigns with good reason within 24 months following the change-in-control, the rTSR RSU agreements provide for full acceleration of vesting of all Converted RSUs. The RSU agreements for Dr. Lee also provide for full acceleration of vesting of all RSUs (or, in the case of performance-based RSUs that are still subject to performance criteria, the actual number of RSUs to vest based upon satisfaction of performance criteria) upon retirement, death or disability, or a pro rata portion of such performance-based RSUs upon early retirement. Retirement, in this context, means a voluntary termination of employment by Dr. Lee after he is at least age 65 and has at least 10 years of service with us, and early retirement, in this context, means a voluntary termination of employment by Dr. Lee after he is at least age 60 and has at least 15 years of service with us. For purposes of the foregoing description of benefits under the employment agreement with Dr. Lee, “cause” will exist if Dr. Lee: (i) commits a felony or engages in fraud, misappropriation or embezzlement, (ii) knowingly fails or refuses to perform his duties in a material way and either the failure or refusal cannot reasonably be cured (as determined by the Company in its reasonable judgment) or he fails to effect a cure within 10 days after the Company notifies him in writing of the failure or refusal, (iii) knowingly causes, or knowingly creates a serious risk of causing, material harm to the Company’s business or reputation or (iv) breaches, in a material way, his employment agreement, the confidential information agreement or any other material agreement between him and the Company, and either the breach cannot be cured (as determined by the Company in its reasonable judgment) or he fails to effect a cure within 10 days after the Company notifies him in writing of the breach.

  92. John T.C. Lee

    | MKS INC. | 2026 PROXY STATEMENT | 74 |

  93. John T.C. Lee

    For purposes of the foregoing description of benefits under the employment agreement with Dr. Lee, subject to compliance with certain procedural requirements, “good reason” for Dr. Lee to resign will exist if, without his express written consent: (i) the Company materially reduces his position, duties, title, reporting relationship, authorities, or responsibilities, (ii) the Company reduces his then-current base salary or target bonus, (iii) the Company changes his principal place of work to a location more than 50 miles from his then-current principal place of work, or (iv) the Company breaches, in a material way, his employment agreement or any other material agreement between him and the Company. The definition of “cause” in Dr. Lee’s RSU agreements is substantially the same as the definition of “cause” in his employment agreement. Subject to compliance with certain procedural requirements, “good reason” for Dr. Lee to resign will exist under these RSU agreements if, without his express written consent: (i) the Company materially reduces his position, duties, or responsibilities, (ii) the Company reduces his then-current base salary, or (iii) the Company changes his principal place of work to a location more than 50 miles from his then-current principal place of work.

  94. Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee

    Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee The following table sets forth the estimated payments and other benefits that Dr. Lee would have been entitled to receive upon termination of his employment effective December 31, 2025:

  95. Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee

    | Termination Circumstance | Cash Severance(1) | Value of Accelerated Unvested Equity | Benefits Continuation | Total | | Termination by the Company Without Cause | $3,885,414 | $- | $40,795(2) | $3,926,209 | | Resignation for Good Reason | $3,885,414 | $- | $40,795(2) | $3,926,209 | | Voluntary Termination or Retirement | $341,664 | $22,443,205(3) | $- | $22,784,869 | | Death or Disability | $1,654,164 | $24,803,266(3) | $- | $26,457,430 | | Within 24 Months Following a Change-in-Control: | | | | | | • Termination by the Company Without Cause | $8,741,664 | $24,803,266(4) | $81,590(5) | $33,626,520 | | • Resignation for Good Reason | $8,741,664 | $24,803,266(4) | $81,590(5) | $33,626,520 |

  96. Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee

    (1) For termination by the Company without cause or resignation for good reason, reflects continuation of base salary for 18 months, a lump sum equal to 1.5 times the annual amount of his target cash incentive compensation, and accrued but unused vacation that we would be required to pay out upon a termination under applicable law and Dr. Lee’s employment agreement. For each of voluntary termination and retirement, reflects accrued but unused vacation. For death and disability, reflects a prorated portion of his then-current year’s target cash incentive compensation and accrued but unused vacation. For termination by the Company without cause or resignation for good reason, each within 24 months following a change in control, reflects a lump sum payment equal to three times his annual base salary, a lump sum payment equal to three times the annual amount of his target cash incentive compensation, a prorated portion of his then-current year’s target cash incentive compensation, and accrued but unused vacation. (2) Reflects our estimated cost for continuation of medical, dental, and vision coverage for 18 months. Upon retirement, death, or disability, RSUs fully vest, subject to achievement of any remaining performance criteria, and upon early retirement, time-based RSUs fully vest and performance-based RSUs still subject to performance criteria vest on a pro rata basis, subject to achievement of such performance criteria. The stated value for death or disability assumes the vesting of the target number of performance-based RSUs for which achievement had yet to be determined at December 31, 2025. The stated value for retirement assumes (i) the vesting of the target number of RSUs under the Adjusted EBITDA RSU agreement granted on February 18, 2025 (for which achievement had yet to be determined at December 31, 2025) and (ii) the vesting of a prorated portion of the target number of RSUs under the rTSR RSU agreements granted on February 15, 2024 and February 18, 2025 (which were each still subject to performance criteria at December 31, 2025), as Dr. Lee met the requirements for early retirement (but not retirement) as of December 31, 2025.

  97. Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee

    | MKS INC. | 2026 PROXY STATEMENT | 75 |

  98. Potential Payments Upon Termination or Change-in-Control Table – John T.C. Lee

    Upon termination by the Company without cause or resignation for good reason, each within 24 months following a change in control, (i) time-based RSUs and performance-based RSUs no longer subject to performance criteria fully vest, (ii) the target number of RSUs under the Adjusted EBITDA RSU agreements still subject to performance criteria vest, and (iii) the Converted RSUs from the rTSR RSU agreements still subject to performance criteria fully vest. The stated value assumes the vesting of (i) the target number of RSUs under the Adjusted EBITDA RSU agreement granted on February 18, 2025 (for which achievement had yet to be determined at December 31, 2025) and (ii) the target number of RSUs under the rTSR RSU agreements granted on February 15, 2024 and February 18, 2025 (which were each still subject to performance criteria at December 31, 2025). (5) Reflects our estimated cost for continuation of medical, dental, and vision coverage for 36 months.

  99. Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner

    Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner The following table sets forth the estimated payments and other benefits that Mr. Mayampurath, Ms. Burke, Mr. Henry, and Mr. Schreiner would have been entitled to receive upon termination of his or her employment effective December 31, 2025:

  100. Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner

    | Termination Circumstance | Cash Severance (1) | Value of Accelerated Unvested Equity | Benefits Continuation | Total | | Termination by the Company Without Cause | | | | | | Ramakumar Mayampurath | $685,096 | $- | $18,849(2) | $703,945 | | Kathleen F. Burke | $746,837 | $- | $27,197(2) | $774,034 | | David P. Henry | $712,447 | $- | $26,541(2) | $738,988 | | James A. Schreiner | $683,847 | $- | $26,541(2) | $710,388 | | Death or Disability | | | | | | Ramakumar Mayampurath | $60,096 | $4,204,406(3) | $- | $4,264,502 | | Kathleen F. Burke | $196,837 | $4,203,462(3) | $- | $4,400,299 | | David P. Henry | $137,447 | $3,291,821(3) | $- | $3,429,268 | | James A. Schreiner | $83,847 | $3,186,668(3) | $- | $3,270,515 | | Voluntary Termination or Retirement | | | | | | Ramakumar Mayampurath | $60,096 | $-(4) | $- | $60,096 | | Kathleen F. Burke | $196,837 | $3,874,437(4) | $- | $4,071,274 | | David P. Henry | $137,447 | $-(4) | $- | $137,447 | | James A. Schreiner | $83,847 | $-(4) | $- | $83,847 | | Within 24 Months Following a Change-in-Control: | | | | | | • Termination by the Company Without Cause | | | | | | • Resignation for Good Reason | | | | | | Ramakumar Mayampurath | $2,325,721 | $4,204,406(5) | $28,273(6) | $6,558,400 | | Kathleen F. Burke | $2,053,087 | $4,203,462(5) | $40,795(6) | $6,297,344 | | David P. Henry | $2,006,197 | $3,291,821(5) | $39,812(6) | $5,337,830 | | James A. Schreiner | $2,033,847 | $3,186,668(5) | $39,812(6) | $5,260,327 |

  101. Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner

    (1) For termination by the Company without cause, reflects a lump sum payment equal to 12 months base salary and accrued but unused vacation that we would be required to pay out upon a termination under applicable law and the applicable employment agreement. For each of death, disability, voluntary termination, and retirement, reflects accrued but unused vacation. For termination by the Company without cause or resignation for good reason, each within 24 months following a change in control, reflects a lump sum payment equal to one and one-half times his or her annual base salary, a lump sum payment equal to one and one-half times the annual amount of his or her target cash incentive compensation, a prorated portion of the then-current year’s target cash incentive compensation, and accrued but unused vacation. (2) Reflects our estimated cost for continuation of medical, dental, and vision coverage for 12 months. (3) Upon death or disability, RSUs fully vest, subject to achievement of any remaining performance criteria. The stated value assumes the vesting of the target number of performance-based RSUs for which achievement had yet to be determined at December 31, 2025. Upon retirement (as defined in the RSU agreements), (i) RSUs for Ms. Burke fully vest, subject to achievement of any remaining performance criteria and (ii) RSUs that were granted to Mr. Mayampurath, Mr. Henry and Mr. Schreiner at least one year prior to the retirement date fully vest, in each case subject to achievement of any remaining performance criteria. Upon early retirement (as defined in Ms. Burke’s RSU agreements), time-based RSUs for Ms. Burke fully vest and performance-based RSUs for Ms. Burke still subject to performance criteria vest on a pro rata basis, subject to achievement of such performance criteria. The stated value for retirement for Ms. Burke assumes (i) the vesting of the target number of RSUs under the Adjusted EBITDA RSU agreement granted on February 18, 2025 (for which achievement had yet to be determined at December 31, 2025) and (ii) the vesting of a prorated portion of the target number of RSUs under the rTSR RSU agreements granted on February 15,

  102. Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner

    | MKS INC. | 2026 PROXY STATEMENT | 78 |

  103. Potential Payments Upon Termination or Change-in-Control Table – Ramakumar Mayampurath, Kathleen F. Burke, David P. Henry, and James A. Schreiner

    2024 and February 18, 2025 (which were each still subject to performance criteria at December 31, 2025), as Ms. Burke met the requirements for early retirement (but not retirement) as of December 31, 2025. Mr. Mayampurath, Mr. Henry, and Mr. Schreiner did not meet the requirements for retirement as of December 31, 2025. Upon termination by the Company without cause or resignation for good reason, each within 24 months following a change in control, (i) time-based RSUs and performance-based RSUs no longer subject to performance criteria fully vest, (ii) the target number of RSUs under the Adjusted EBITDA RSU agreements still subject to performance criteria vest, and (iii) the Converted RSUs from the rTSR RSU agreements still subject to performance criteria fully vest. The stated value assumes the vesting of (i) the target number of RSUs under the Adjusted EBITDA RSU agreements granted on February 18, 2025 and August 4, 2025 (for which achievement had yet to be determined at December 31, 2025) and (ii) the target number of RSUs under the rTSR RSU agreements granted on February 15, 2024, February 18, 2025 and August 4, 2025 (which were each still subject to performance criteria at December 31, 2025). (6) Reflects our estimated cost for continuation of medical, dental, and vision coverage for 18 months.

  104. CEO Pay Ratio

    CEO Pay Ratio We disclose the ratio of our median employee’s annual total compensation to our principal executive officer’s annual total compensation to provide a measure of equitability of pay within our Company. We believe our compensation philosophy and process yield an equitable result for all of our employees. During 2025, our principal executive officer was our Chief Executive Officer, John T.C. Lee. For 2025, the annual total compensation for Dr. Lee was $12,961,940 and the annual total compensation for our median employee was $74,240, resulting in a pay ratio of approximately 175:1. In accordance with applicable SEC rules, we identified the median employee as of December 1, 2025 (the median employee determination date) by (i) aggregating for each applicable employee (A) annual base salary for salaried employees (or hourly rate multiplied by expected annual work schedule for hourly employees), (B) target bonus and commissions (or local country equivalent), (C) actual overtime and double-time received for 2025, and (D) the accounting value of any equity granted during 2025 and (ii) ranking this compensation measure for our employees from lowest to highest. This calculation was performed for all employees, excluding Dr. Lee, whether employed on a full-time, part-time, or seasonal basis. For purposes of identifying the median employee, we converted amounts paid in foreign currencies to U.S. Dollars based on the applicable average exchange rates for December 2025. We changed the median employee determination date to December 1 from our prior median employee determination date of December 18 in order to provide our subsidiaries and international payroll providers with additional time to gather compensation data for our active employee population. The pay ratio reported above is a reasonable estimate calculated in a manner consistent with SEC rules based on our internal records and the methodology described above. Because the SEC rules for identifying the median compensated employee and calculating the pay ratio based on that employee’s annual total compensation allow companies to adopt a variety of methodologies, apply certain exclusions, and make reasonable estimates and assumptions that reflect their employee populations and compensation practices, the pay ratio reported by other companies may not be comparable to the pay ratio reported above, as other companies have different employee populations and compensation practices and may utilize different methodologies, exclusions, estimates, and assumptions in calculating their own pay ratios.

  105. CEO Pay Ratio

    | MKS INC. | 2026 PROXY STATEMENT | 79 |

  106. Pay Versus Performance

    Pay Versus Performance

  107. Tabular Disclosure of Compensation Actually Paid versus Performance

    Tabular Disclosure of Compensation Actually Paid versus Performance The following table discloses information on “compensation actually paid,” or CAP, to our principal executive officer, or PEO, and the average CAP to our other Named Executive Officers, or non-PEO NEOs, during the previous five fiscal years, alongside Company total shareholder return, or TSR, peer group TSR, net income (loss), and the Company-selected financial performance measure of Adjusted EBITDA.

  108. Tabular Disclosure of Compensation Actually Paid versus Performance

    | | Summary | | Average Summary Compensation Table Total | Average | Value of Initial Fixed $100 Investment Based On: | | | | | Year | Compensation Table Total for PEO(1) | CAP to PEO(2) | for Non-PEO NEOs(3) | CAP to Non-PEO NEOs(4) | TSR | Peer Group TSR(5) | Net Income (Loss) ($ millions) | Adjusted EBITDA ($ millions)(6) | | 2025 | $12,961,940 | $24,972,850 | $2,829,657 | $4,634,447 | $110.36 | $205.05 | $295 | $966 | | 2024 | $8,760,125 | $7,389,231 | $1,953,259 | $1,818,697 | $71.50 | $142.03 | $190 | $927 | | 2023 | $7,906,628 | $13,215,067 | $2,117,764 | $3,083,750 | $69.95 | $121.68 | $(1,841) | $863 | | 2022 | $8,058,382 | $3,494,929 | $2,046,599 | $759,709 | $57.06 | $101.05 | $333 | $854 | | 2021 | $7,596,357 | $11,383,747 | $2,311,088 | $3,336,104 | $116.37 | $129.18 | $551 | $868 |

  109. Tabular Disclosure of Compensation Actually Paid versus Performance

    (1) These amounts reflect the total compensation of our PEO for the previous five years as calculated in accordance with the requirements of Item 402(c) of Regulation S-K, or Item 402(c). Dr. Lee served as our PEO each year presented in the table. (2) These amounts reflect CAP for our PEO for the previous five years as calculated in accordance with Item 402(v) of Regulation S-K, or Item 402(v). The table below summarizes the adjustments required to reconcile total compensation from the summary compensation table to CAP of our PEO for the previous five years.

  110. Tabular Disclosure of Compensation Actually Paid versus Performance

    | Adjustment | 2025 | 2024 | 2023 | 2022 | 2021 | | Total Compensation from Summary Compensation Table | $12,961,940 | $8,760,125 | $7,906,628 | $8,058,382 | $7,596,357 | | Less Fair Value of Equity Awards Reported in the Summary Compensation Table in the Covered Year | $(10,133,327) | $(7,388,552) | $(5,900,090) | $(5,909,984) | $(4,478,002) | | Plus Fair Value of Covered Year Equity Awards Unvested at Fiscal Year-End | $17,901,722 | $4,616,322 | $9,488,697 | $5,503,956 | $7,086,150 | | Year-Over-Year Change in Fair Value of Prior Years’ Equity Awards Unvested at Fiscal Year-End | $4,208,225 | $121,996 | $989,809 | $(3,482,934) | $698,646 | | Change as of the Vesting Date (From the End of the Prior Fiscal Year) in Fair Value of Prior Years’ Equity Awards Vested in the Covered Year | $34,290 | $1,279,340 | $730,023 | $(674,491) | $480,596 | | Compensation Actually Paid | $24,972,850 | $7,389,231 | $13,215,067 | $3,494,929 | $11,383,747 |

  111. Tabular Disclosure of Compensation Actually Paid versus Performance

    These amounts reflect the average total compensation of Mr. Mayampurath, Ms. Burke, Mr. Henry, and Mr. Schreiner for 2025; Mr. Mayampurath, Ms. Burke, Mr. Henry, Mr. Schreiner, and Mr. Bagshaw for 2024; Ms. Burke, Mr. Henry, Mr. Schreiner, and Mr. Bagshaw for 2023 and 2022; and Ms. Burke, Mr. Schreiner, Mr. Bagshaw, and Dr. Mark Gitin, our former Executive Vice President and General Manager, Photonics Solutions Division, for 2021, each as calculated in accordance with the requirements of Item 402(c).

  112. Tabular Disclosure of Compensation Actually Paid versus Performance

    | MKS INC. | 2026 PROXY STATEMENT | 80 |

  113. Tabular Disclosure of Compensation Actually Paid versus Performance

    These amounts reflect the average CAP for our non-PEO NEOs for the previous five years, each as calculated in accordance with the requirements of Item 402(v). The table below summarizes the adjustments required to reconcile average total compensation from the summary compensation table to average CAP for our non-PEO NEOs for the previous five years.

  114. Tabular Disclosure of Compensation Actually Paid versus Performance

    | Adjustment | 2025 | 2024 | 2023 | 2022 | 2021 | | Average Total Compensation from Summary Compensation Table | $2,829,657 | $1,953,259 | $2,117,764 | $2,046,599 | $2,311,088 | | Less Average Fair Value of Equity Awards Reported in the Summary Compensation Table in the Covered Year | $(1,524,347) | $(1,154,794) | $(1,130,850) | $(1,132,739) | $(1,020,430) | | Plus Average Fair Value of Covered Year Equity Awards Unvested at Fiscal Year-End | $2,682,749 | $833,417 | $1,742,044 | $1,025,706 | $1,577,301 | | Year-Over-Year Change in Average Fair Value of Prior Years’ Equity Awards Unvested at Fiscal Year-End | $567,015 | $10,766 | $198,872 | $(805,502) | $305,120 | | Change as of the Vesting Date (From the End of the Prior Fiscal Year) in Average Fair Value of Prior Years’ Equity Awards Vested in the Covered Year | $79,373 | $176,049 | $155,920 | $(374,355) | $163,025 | | Average Compensation Actually Paid | $4,634,447 | $1,818,697 | $3,083,750 | $759,709 | $3,336,104 |

  115. Tabular Disclosure of Compensation Actually Paid versus Performance

    (5) Peer Group TSR represents TSR for the S&P 1500 Composite Electronic Equipment Instruments & Components Index, which is the industry peer group used for purposes of Item 201(e) of Regulation S-K. We selected this measure as the most important in linking 2025 NEO CAP to Company performance because long-term equity incentive compensation comprised the largest percentage of total NEO compensation and Adjusted EBITDA was the financial measure we used to determine achievement under 70% of the performance-based RSUs granted in 2025. Adjusted EBITDA is defined as the Company’s GAAP operating income, excluding any charges or income not related to the operating performance of the Company, plus depreciation and stock compensation expense. For 2024, Adjusted EBITDA excludes the Non-Executive Bonus Adjustment. For 2022, Adjusted EBITDA excludes the results of Atotech, which we acquired in August 2022. For 2021, Adjusted EBITDA excludes the results of Photon Control, which we acquired in July 2021. For further information regarding Adjusted EBITDA and its function in our executive compensation program, see “Executive Compensation — Compensation Discussion and Analysis — Elements of Compensation — Long-Term Equity Incentive Compensation” above.

  116. Tabular Disclosure of Compensation Actually Paid versus Performance

    | MKS INC. | 2026 PROXY STATEMENT | 81 |

  117. Disclosure of the Relationship Between Compensation Actually Paid and Financial Performance Measures

    Disclosure of the Relationship Between Compensation Actually Paid and Financial Performance Measures The following two graphs further illustrate the relationship between the pay and performance figures that are included in the pay versus performance tabular disclosure above. The first graph below illustrates the relationship among PEO CAP, Average Non-PEO NEO CAP, Company total shareholder return (MKS TSR), and S&P 1500 Composite Electronic Equipment Instruments & Components Index total shareholder return (Peer Group TSR). The second graph below illustrates the relationship among PEO CAP, Average Non-PEO NEO CAP, Company Net Income (Loss), and Company Adjusted EBITDA.

  118. Disclosure of the Relationship Between Compensation Actually Paid and Financial Performance Measures

    | MKS INC. | 2026 PROXY STATEMENT | 82 |

  119. Tabular Disclosure of Most Important Measures Linking Compensation Actually Paid During 2025 to Company Performance

    Tabular Disclosure of Most Important Measures Linking Compensation Actually Paid During 2025 to Company Performance We disclose below the most important measures we used to link 2025 NEO CAP to Company performance. For 2025, Named Executive Officers were granted performance-based equity awards, based on achievement of Adjusted EBITDA and rTSR. For 2025, Named Executive Officers were also eligible for variable cash compensation based on achievement of non-GAAP operating income and adjusted net debt. For further information regarding these measures and their function in our executive compensation program, see “Executive Compensation — Compensation Discussion and Analysis” above.