DEF 14A of Amentum Holdings, Inc., Dec 19, 2025

DEF 14A of Amentum Holdings, Inc.

Filed Dec 19, 2025 · FY20250001104659-25-123111

Open on EDGAR

  1. Our Board of Directors

    Our Board of Directors Each of our directors is elected by our stockholders on an annual basis to serve until the next annual meeting and until their respective successors are elected and qualified, or until such director’s earlier death, resignation or removal. Each of our current directors has been nominated for election to the Board, and you can find additional information regarding our Board nominees under “Proposal 1: Election of Directors” beginning on page 6. Our board of directors consists of 13 members and reflects a range of ages, with three directors between ages 35 and 55, six directors between ages 56 and 67, and four directors between ages 68 and 78. Three of the directors identify themselves as women and one as African American.

  2. Our Board of Directors

    | | | | Committee Membership | | | | Name | Director Since | Independent | Audit | Compensation | Nominating & Governance | | 2024 Director Nominees | | | | | | | Steven J. Demetriou1 | 2024 | | | | | | John Heller2 | 2024 | | | | | | Benjamin Dickson3 | 2024 | I | | M | | | General Vincent K. Brooks | 2024 | I | M | | M | | General Ralph E. Eberhart | 2024 | I | | M | | | Alan E. Goldberg | 2024 | I | | | | | S. Leslie Ireland | 2024 | I | M | M | | | Barbara L. Loughran | 2024 | I | M | | C | | Sandra E. Rowland | 2024 | I | C | | | | Christopher M.T. Thompson | 2024 | I | | | | | Russell Triedman | 2024 | I | | C | M | | John Vollmer | 2024 | I | | | | | Connor Wentzell | 2024 | I | | | M | | C Committee Chair I Independent Director M Member | | | | | |

  3. Our Board of Directors

    1 Executive Chair 2 Chief Executive Officer 3 Lead Independent Director

  4. Election of Directors

    Election of Directors Each of our current directors has been nominated for election to the Board for a one-year term, expiring at the 2027 Annual Meeting of Stockholders and when his or her successor is duly elected and qualified, or until such director’s earlier death, resignation or removal. To be elected in an uncontested election, a nominee must receive a majority of the votes validly cast with respect to that nominee’s election at an annual meeting at which a quorum has been established. To be elected in a contested election, a nominee must receive the vote of a plurality of the votes validly cast at an annual meeting at which a quorum has been established.

  5. Board Skills Matrix

    Board Skills Matrix The Nominating and Governance Committee and the Board believe that each director nominee is well qualified for the role in terms of skills and experiences relevant to the Company, as reflected in the board skills matrix below. Collectively, the director nominees bring significant public company, financial, government, and strategic experience that will enable the Board to provide sound and prudent guidance with respect to the Company’s operations and interests and that will further the long-term interests of the Company’s stockholders.

  6. Board Skills Matrix

    | | Steven J. Demetriou | John Heller | Benjamin Dickson | General Vincent K. Brooks | General Ralph E. Eberhart | Alan E. Goldberg | S. Leslie Ireland | Barbara L. Loughran | Sandra E. Rowland | Christopher M.T. Thompson | Russell Triedman | John Vollmer | Connor Wentzell | | Independent Director | | | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Audit Committee Financial Expert (SEC Rules) | | | | | | | | ● | ● | | | | | | Financially Literate (NYSE Rules) | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Security Clearance | ● | ● | | ● | ● | | ● | | | | ● | ● | | | Experience | | | | | | | | | | | | | | | Chief Executive Officer (CEO) Public Company | ● | ● | | | | | | | | ● | | | | | CEO Private Company | ● | ● | | | ● | ● | | | | ● | | ● | | | Chief Financial Officer (CFO) | | ● | | | | | | | ● | | | ● | | | Government / Military | | ● | | ● | ● | | ● | | | | | | | | International Operations | ● | ● | | ● | ● | ● | ● | ● | ● | ● | ● | ● | | | Strategic Competencies | | | | | | | | | | | | | | | Financial (Reporting, Auditing, Internal Controls) | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Strategy / Business Development / Mergers & Acquisitions (M&A) | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Talent / Organization Development | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Project Delivery | ● | ● | ● | ● | ● | ● | ● | ● | | ● | ● | ● | ● | | Legal / Risk Management / Compliance | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Public Company / Governance | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | | Technology & Innovation | ● | ● | ● | ● | ● | | ● | ● | ● | ● | | ● | ● | | Data Privacy & Security / Cybersecurity | | | ● | ● | | | ● | | | | | | ● |

  7. Director Nominees

    Director Nominees The thirteen nominees for election as directors are listed below. If elected, the nominees for election as directors will serve for one-year terms and until their successors are elected and qualify. Unless you instruct us on the proxy card to vote differently, we will vote signed, returned proxies FOR the election of such nominees. If for any reason any nominee cannot or will not serve as a director, we may vote such proxies for the election of a substitute nominee designated by the Board.

  8. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Steven (Steve) J. Demetriou | | | Age: 67 Director since 2024 Executive Chair | Steve Demetriou is the executive chair of the board of directors of Amentum. He joined Jacobs Solutions Inc. (Jacobs) as CEO in 2015. In 2016, he became chair and chief executive officer of Jacobs. In January 2023, upon retiring as chief executive officer, he continued as the executive chair of Jacobs’ board of directors, where he served until the closing of Amentum’s merger with Jacobs’ Critical Mission Solutions and Cyber and Intelligence businesses. During his tenure as CEO, Mr. Demetriou steered a profound reshaping of Jacobs’ business portfolio, operations and culture. Under his leadership, the company accelerated profitable growth and transformed into a leading, next-generation solutions provider by tackling some of the world’s biggest challenges for thriving cities, resilient environments, mission-critical outcomes, operational advancement, scientific discovery, and cutting-edge manufacturing. Mr. Demetriou’s broad international business perspectives are the product of more than 35 years in leadership and senior management roles across a wide range of industries. This includes serving as president and CEO of Noveon Inc. (2001 – 2004) and chairman and CEO of Aleris Corporation (2004 – 2015). He holds a Bachelor of Science degree in chemical engineering from Tufts University. In addition to serving on Amentum’s board, Mr. Demetriou also serves on the boards of FirstEnergy Corp. and Arcosa Inc. Specific qualifications, experience, skills, and expertise include: • Public company CEO, Executive Chair, and directorship experience; • Core business skills, including financial and strategic planning; and • Deep understanding of our Company, its history, and culture. |

  9. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | John Heller | | | Age: 63 Director since 2024 Chief Executive Officer | As the chief executive officer for Amentum, John Heller’s responsibilities include planning and directing the strategy and execution of the operating activities for all 50,000 employees in approximately 80 countries around the world. Prior to the Amentum-Jacobs’ Critical Mission Solutions business merger, Mr. Heller was the chief executive officer of the legacy Amentum company since 2022, where he led the company’s integration of two multi-billion dollar acquisitions. Under his leadership, Amentum transformed into an industry-leading provider of engineering, system integration, and project management services to the U.S. government and partners. Before his role at Amentum, Mr. Heller served as chief executive officer and president at PAE from 2013 to 2021. Prior to that, he served as senior vice president and chief operating officer of Engility Corporation after the company was spun off from L-3 Communications from 2012 to 2013. He also held several leadership positions at Harris Corporation from 2007 to 2012, including president of Harris IT Services, served as CEO of Netco, Inc., a Cerberus Capital Management portfolio company from 2004 to 2006, and held the president and chief operating officer role at Multimax, Inc. from 2006 to 2007. Mr. Heller started his career in the U.S. Army serving in various leadership positions as a logistics officer. He then attended graduate business school and joined Deloitte Consulting. Following a decade in the consulting field, Mr. Heller attained his first CEO position at Rentport, Inc., a portfolio company of Catterton Partners (now L Catterton), a venture capital and private equity firm. Mr. Heller graduated from the U.S. Military Academy at West Point and earned a master’s degree in business administration from the University of Pittsburgh. Today he serves on their Chancellor’s Global Advisory Council. In recognition of his achievements and contributions in the field of business, Mr. Heller was also named the university’s Katz Graduate School Distinguished Alumni Honoree. As part of his support to the government services industry, Mr. Heller also serves as the Vice-chair for the Professional Services Council board of directors and executive committee. Mr. Heller is a well-recognized leader in the government contracting industry, being awarded 2024 CEO of the Year by WashingtonExec and 2024 ACG CEO of the Year; he has been in the Washington100 list of top executives multiple times over his career. Specific qualifications, experience, skills, and expertise include: • Operating and management experience, including as the CEO of public and privately owned companies; • Core business skills, including financial and strategic planning; and • Deep understanding of our Company, its history, and culture. |

  10. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Benjamin Dickson | | | Age: 44 Director since 2024 Lead Independent Director Committee: • Compensation | Benjamin Dickson is the lead independent director on Amentum’s board of directors. He currently serves as a managing director of American Securities LLC, which he joined in 2011. He is a former member of the board of managers of the general partner of Amentum Joint Venture LP. Mr. Dickson has extensive experience serving as a director of private companies. In addition to serving on the board of Amentum, Mr. Dickson serves on the board of directors of several current American Securities LLC portfolio companies, including serving as chairman of the board of directors of NAPA and SimonMed and as a director of The Aspen Group. Prior to joining American Securities LLC, Mr. Dickson served as the director of corporate development at Active Interest Media, as an investment professional with GTCR and Wind Point Partners, and as a management consultant with McKinsey & Company. Mr. Dickson holds Bachelor of Science degrees in accounting and finance from Indiana University’s Kelley School of Business and a Master of Business Administration degree from Northwestern University’s Kellogg School of Management. He brings more than 19 years of private equity investing and director experience. Specific qualifications, experience, skills, and expertise include: • Private equity investing and directorship experience; • Operating and management experience; and • Core business skills, including financial and strategic planning. |

  11. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | General Vincent K. Brooks (U.S. Army, retired) | | | Age: 67 Director since 2024 Independent Committees: • Audit • Nominating & Governance | General Vincent K. Brooks is a member of Amentum’s board of directors and has served as a principal of WestExec Advisors LLC since 2020. He served on the Jacobs board of directors from 2020 until the closing of Amentum’s merger with Jacobs’ Critical Mission Solutions and Cyber and Intelligence businesses. He is a former four-star general in the United States Army, from which he retired in 2019. He served as commander of Korean and U.S. combined forces in the Republic of Korea from 2016 to 2018 and held numerous high-level command and staff positions within the armed forces from 1980 to 2019. He currently serves as a director of and as the chair of the nominating and corporate governance committee of Diamondback Energy Inc. where he also serves on the Audit Committee and on the Safety, Sustainability and Corporate Responsibility Committee. He is a former director of Verisk Analytics Inc. where he served from 2020 to 2025. General Brooks also serves as vice chair of the Gary Sinise Foundation, is a life member of the Council on Foreign Relations, and serves as a distinguished fellow at the University of Texas at Austin Clements Center for National Security and Strauss Center for International Security and Law. He previously served as a member of the CIA Director’s External Advisory Board, as a member of the Defense Advisory Committee on Diversity and Inclusion, as the Class of 1951 Distinguished Chair for the Study of Leadership at the U.S. Military Academy at West Point, as the Chair and President of the Korea Defense Veterans Association, and as a visiting senior fellow at Harvard Kennedy School Belfer Center for Science and International Affairs. General Brooks holds a Bachelor of Science degree in engineering from the U.S. Military Academy at West Point and a master’s degree in military art and science from the U.S. Army School of Advanced Military Studies at Fort Leavenworth, Kansas. General Brooks brings to our board of directors valuable leadership skills and expertise developed through his military service. His areas of expertise include leadership in complex organizations, national security, international relations, geopolitical dynamics, risk assessment and mitigation, military operations, combating terrorism, countering the proliferation of weapons of mass destruction, cybersecurity, and inclusion and diversity. Specific qualifications, experience, skills, and expertise include: • Significant government experience, particularly in national security, international relations, and military operations; • Operating and management experience; and • Public company directorship and committee experience. |

  12. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | General Ralph E. (Ed) Eberhart (U.S. Air Force, retired) | | | Age: 78 Director since 2024 Independent Committee: • Compensation | General Ralph E. Eberhart is a member of Amentum’s board of directors and served on the board of directors of Jacobs from 2012 until the closing of Amentum’s merger with Jacobs’ Critical Mission Solutions and Cyber and Intelligence businesses. General Eberhart is a former four star general in the United States Air Force, a rank he held from 1997 to 2005. General Eberhart also held numerous high-level command and staff positions within the Air Force and the Department of Defense from 1968 to 2005. He is a former commander of the U.S. Northern Command, North American Aerospace Defense Command, U.S. Space Command, Air Force Space Command, Air Combat Command & U.S. Forces, Japan. He also served as vice chief of the United States Air Force. He has served as the chair of the board of VSE Corp. since 2019 and has served on its board since 2007. He also serves on the board of Segs4Vets. In the past, General Eberhart previously served as the chair of the board of Triumph Group, Inc. and on the boards of TERMA North America Inc. and Rockwell Collins. General Eberhart is the chair of the American Air Museum in Britain, serves on the board of trustees of Palmer Land Conservancy and is a trustee of the Falcon Foundation. He is a member of the Council of Foreign Relations and the Colorado Thirty Group. General Eberhart brings extensive leadership skills developed through his military service. General Eberhart holds a Bachelor of Science degree in political science from the United States Air Force Academy and a master’s degree in political science from Troy State University. His 36-year military career provides our board of directors with valuable insights and knowledge into leadership, government and military issues. Specific qualifications, experience, skills, and expertise include: • Significant government experience, particularly in military operations; • Public and private company directorship and committee experience; and • Operating and management experience. |

  13. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Alan E. Goldberg | | | Age: 71 Director since 2024 Independent | Alan Goldberg is a member of the board of directors of Amentum and is the co-founder and chief executive officer of Lindsay Goldberg, positions he has held since the firm’s inception in 2001. Prior to co-founding Lindsay Goldberg, he held several leadership positions at Morgan Stanley, including serving as chairman and chief executive officer of Morgan Stanley Private Equity. Mr. Goldberg has extensive experience serving as a director on the boards of directors of private and public companies, including most recently serving as a director on the boards of directors of Reign Research Holdings and Stelco Holdings Inc. (TSX: STLC). Mr. Goldberg holds a Bachelor of Arts degree in economics and philosophy and a Master of Business Administration degree from New York University, and a Juris Doctor degree from Yeshiva University. He brings more than 40 years of investing and public and private company director experience in the industrials, professional services and healthcare industries to our board of directors. Specific qualifications, experience, skills, and expertise include: • Private and public company directorship experience; • Expertise in the financial, industrial, professional services, and healthcare industries; and • Core business skills, including financial and strategic planning. |

  14. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | S. Leslie Ireland | | | Age: 66 Director since 2024 Independent Committees: • Audit • Compensation | Leslie Ireland is a member of the board of directors of Amentum and served in the U.S. Intelligence Community for approximately 31 years. In her final assignment in federal service, Ms. Ireland was the Assistant Secretary for Intelligence and Analysis of the U.S. Department of the Treasury, and the National Intelligence Manager for Threat Finance for the Office of the Director of National Intelligence. Before joining the Treasury in 2010, Ms. Ireland was the daily intelligence briefer for President Barack Obama. She also served as the Iran Mission Manager, responsible for overseeing the intelligence process on Iran for the entire U.S. government. Ms. Ireland worked at the Central Intelligence Agency for 25 years in positions of increasing responsibility, including work on assignments focused on the Middle East and weapons of mass destruction. She retired from federal service in November 2016. Ms. Ireland served as a director of Citigroup Inc. from October 2017 to April 2025. She currently serves on the board of the Stimson Center, a non-profit organization. She is a member of the Cyber Advisory Board for the CEO of Chubb Insurance and Chubb’s Executive Management Team. She is also a member of Tapestry Networks Cyber Risk Director Network. Ms. Ireland holds a bachelor’s degree from Franklin & Marshall College and a master’s degree from Georgetown University. She brings more than 30 years of in-depth experience in the Intelligence Community to our board of directors. Specific qualifications, experience, skills, and expertise include: • Significant government experience, particularly in national security and the Intelligence Community; • Public company and not-for-profit organization directorship experience; and • Core business skills, including financial and strategic planning. |

  15. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Barbara (Barb) L. Loughran | | | Age: 62 Director since 2024 Independent Committees: • Audit • Nominating & Governance (Chair) | Barb Loughran is a member of the board of directors of Amentum and served on the board of directors of Jacobs from 2019 until the closing of Amentum’s merger with Jacobs’ Critical Mission Solutions and Cyber and Intelligence businesses. She served as Jacobs’ audit committee chair and on the enterprise risk & ESG committee. Previously, Ms. Loughran was a partner at PricewaterhouseCoopers LLP (PwC) until 2018, serving global public company clients across a wide range of industries. Additionally, she served as a partner in PwC’s national office working with the Securities and Exchange Commission and clients as they accessed the capital markets and responded to regulatory requirements. Ms. Loughran has also been on the board of Armstrong World Industries since 2019, serving as audit committee chair and on the nominating, governance & sustainability and finance committees. She is also an advisory board member for Conquer.AI, an AI consulting group. Ms. Loughran holds a bachelor’s degree from Franklin & Marshall College and a Master of Business Administration degree from the University of Pennsylvania’s Wharton School. Ms. Loughran brings more than 35 years of global experience working with Fortune 500 executives and boards as they navigate strategic, transformational and operational issues. Specific qualifications, experience, skills, and expertise include: • Broad and in depth industry experience across professional services, industrial, manufacturing, engineering and consumer products; • Public company directorship and audit committee chair experience; and • Core business skills, including M&A, risk management, accounting, financial and strategic planning, and corporate governance. |

  16. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Sandra E. Rowland | | | Age: 54 Director since 2024 Independent Committee: • Audit (Chair) | Sandra Rowland is a member of the board of directors of Amentum. From 2020 to 2023, Ms. Rowland served as senior vice president and chief financial officer of Xylem Inc., a leading water technology company, during which she played a central role in the company’s $7.5 billion acquisition and integration of Evoqua Water Technologies Corp., and served as a senior advisor from 2023 to 2024. From 2015 to 2020, Ms. Rowland served as executive vice president, and chief financial officer of Harman International Industries Inc., a global leader in connected car and audio solutions. She was instrumental in Samsung Electronics’ acquisition of Harman, a NYSE publicly traded Fortune 500/S&P 500 Company in 2017. From 2012 to 2014, Ms. Rowland led corporate development and investor relations. Earlier in her career, Ms. Rowland held various financial leadership positions at Eastman Kodak Company and PricewaterhouseCoopers LLP. Ms. Rowland currently serves on the board of directors and the audit and human resources committees of Oshkosh Corporation, a leading innovator of purpose-built vehicles and equipment. She also serves as board member and chair of the audit committee of Fortifi Food Processing Solutions, a portfolio company of KKR & Company Inc. Ms. Rowland holds a bachelor’s degree in economics and business from Lafayette College and a Master of Business Administration degree from the University of Rochester’s William E. Simon School of Business. She brings more than 30 years of experience in financial strategy, investor relations, mergers and acquisitions, and accounting and finance operations to our board of directors. Specific qualifications, experience, skills, and expertise include: • Expertise in finance and accounting operations, financial strategy, investor relations, and mergers and acquisitions; • Public company directorship and audit committee experience; and • Core business skills, including financial and strategic planning. |

  17. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Christopher M.T. Thompson | | | Age: 77 Director since 2024 Independent | Christopher Thompson is a member of the board of directors of Amentum and served on the board of Jacobs from 2012 and from 2020 as Lead Independent Director until the closing of Amentum’s merger with Jacobs’ Critical Mission Solutions and Cyber and Intelligence businesses. Mr. Thompson has served on the boards of directors of Royal Gold Inc. from 2013 to 2020, Golden Star Resources Ltd. from 2010 to 2015, and Teck Resources Limited from 2003 to 2014. Additionally, from 2002 to 2005, he served as chairman of the World Gold Council and from 1998 to 2005, he served as director, chairman and chief executive officer of Gold Fields Ltd., a gold mining company. Earlier in his career, Mr. Thompson founded and led the formation of Castle Group Inc., a manager of institutionally funded venture capital partnerships that invested in the development of new gold mines globally, from 1985 to 1998. Prior to his experience at Castle Group Inc., Mr. Thompson was a mining analyst, partner and director of Gordon Securities in Toronto from 1978 to 1982. In addition, from 1971 to 1978, he worked for the Anglo American Corporation in South Africa and Canada as assistant divisional manager of the Gold Division and, subsequently, the Finance Division. He has also served on private boards of directors and engaged with the community, including, from 2013 to 2017, as a member of the board of directors of The Colorado School of Mines Foundation, and from 1998 to 2002, as a member of the board of directors and vice president of the South African Chamber of Mines and a member of the board of directors of Business Against Crime South Africa. Mr. Thompson holds a bachelor’s degree in law and economics from Rhodes University in South Africa, and a master’s degree in business management from Bradford University in the United Kingdom. He has an extensive background in international operations, finance and strategic leadership in a range of industries, including investments and mining. Mr. Thompson brings valuable insight and independent leadership to our board of directors regarding the day-to-day operations of large global organizations, risk management and corporate best practices. Specific qualifications, experience, skills, and expertise include: • Public and private company CEO and directorship experience; • Expertise in finance, risk management, and global businesses; and • Core business skills, including financial and strategic planning. |

  18. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Russell Triedman | | | Age: 56 Director since 2024 Independent Committees: • Compensation (Chair) • Nominating & Governance | Russell Triedman is a member of the board of directors of Amentum and a managing partner at Lindsay Goldberg, which he joined at its inception in 2001. He is a former member of the board of managers of the general partner of Amentum Joint Venture LP. Mr. Triedman has extensive experience serving as a director of private and public companies and serves in such roles at companies owned by Lindsay Goldberg funds. Mr. Triedman holds a Bachelor of Science degree in applied mathematics and economics from Brown University and a Juris Doctor degree from the University of Chicago Law School. He brings more than 25 years of investing and director experience in the industrials, government contracting, and other professional services industries to our board of directors. Specific qualifications, experience, skills, and expertise include: • Public and private company directorship experience; • Private equity investing experience; and • Core business skills, including financial and strategic planning. | | John Vollmer | | | Age: 68 Director since 2024 Independent | John Vollmer is a member of the board of directors of Amentum and the former chairman and member of the board of managers of the general partner of Amentum Joint Venture LP. Previously, Mr. Vollmer served as chief executive officer of Amentum from 2020 to 2022, as president of the AECOM Management Services Group from 2016 to 2020, and as group and executive vice president and chief operating officer of URS Corporation Federal Services from 2009 to 2015. Additionally, he is a member of the First Tee of Greater Washington DC Capital Campaign Cabinet, supporting youth development that empowers young people through golf and life skills. Mr. Vollmer graduated from Flagler College with a degree in business economics. He brings more than 40 years of experience working with military and other federal agency clients providing IT, communications and command and control solutions globally to our board of directors. Specific qualifications, experience, skills, and expertise include: • Chief executive officer and chief operating officer experience; • Understanding of government contracting; and • Deep understanding of our Company, its history, and culture. |

  19. Director Nominees

    | Director | Principal Occupation, Business Experience and Other Directorships Held | | Connor Wentzell | | | Age: 35 Director since 2024 Independent Committee: • Nominating & Governance | Connor Wentzell is a member of the board of directors of Amentum. Mr. Wentzell currently serves as a principal of American Securities LLC, which he joined in 2014. He is a former member of the board of managers of the general partner of Amentum Joint Venture LP. He also serves as a director of American Securities LLC portfolio companies, including currently serving as a director of Learning Care Group and previously serving as a director of Blue Bird Corporation (NASDAQ: BLBD). Prior to joining American Securities LLC, Mr. Wentzell worked at Evercore Partners from 2012 to 2014. Mr. Wentzell holds a Bachelor of Arts degree in economics from Harvard University and a Master of Business Administration degree from the University of Pennsylvania’s Wharton School of Business. He brings more than 10 years of private equity investing and director experience in the government services, aerospace and defense, and financial services industries to our board of directors. Specific qualifications, experience, skills, and expertise include: • Private equity investing and directorship experience; • Expertise in the aerospace & defense and financial services industries; and • Core business skills, including financial and strategic planning. |

  20. Director Nominees

    | The Board of Directors recommends a vote FOR each of the director nominees. |

  21. Director Nominees

    CORPORATE GOVERNANCE AND GENERAL INFORMATION CONCERNING THE BOARD OF DIRECTORS AND COMMITTEES

  22. Our Board of Directors

    Our Board of Directors The business and affairs of the Company are managed under the direction and supervision of the Board. The principal duty of the Board is to exercise its oversight powers in accordance with its fiduciary duties to the Company and in a manner it reasonably believes to be in the best interests of the Company and its stockholders. Accordingly, the Board oversees the strategy, operations, and management of the Company. The Board is responsible for guiding and supervising management, which has responsibility for the day-to-day strategy and operations of the Company. The Board’s objective is to maximize stockholder value by supporting the long-term success of the Company. The Board will generally have at least four regular meetings per year, and special meetings as necessary. The Board meets in executive session and the independent directors meet in executive session during each regular meeting. Consistent with the Company’s Corporate Governance Guidelines, Benjamin Dickson was appointed to serve as the Lead Independent Director, effective as of the closing of the Transaction. The Lead Independent Director’s responsibilities include presiding over executive sessions of the independent directors; presiding, if the Chair is absent, at Board meetings; and consulting with the Chair to set meeting agendas. The Board and its committees establish annual calendars of activities to guide the development of their agendas during the year. The Executive Chair, in consultation with the Chief Executive Officer, the Lead Independent Director and any other executive officers as needed, and after taking into account suggestions from other members of the Board, sets the agenda for each Board meeting and distributes such agenda in advance of any meeting to each director. Directors are encouraged to raise topics that are not on a meeting agenda and to suggest topics for future agendas. Each director is provided written materials in advance of each meeting, and the Board and its committees provide feedback to, and make requests of, management at each of their meetings.

  23. Selection of Nominees for Election to the Board

    Selection of Nominees for Election to the Board Subject to the requirements of the amended and restated certificate of incorporation, the amended and restated bylaws, and the Stockholders Agreement, the Nominating and Governance Committee recommends to the Board appropriate criteria for the selection of new directors based on the strategic needs of the Company and the Board, and periodically reviews the criteria adopted by the Board and, if deemed desirable, recommends to the Board changes to such criteria. The policy of the Board is that directors should possess the highest personal and professional ethics, integrity and values, and be committed to representing the long-term interests of the Company’s stockholders. The Board seeks members who reflect a range of talents, experience, skills, and expertise, particularly in the areas of accounting and finance, management, leadership, business operations, risk management and corporate governance, in the Company’s industry and the markets the Company serves, sufficiently to provide sound and prudent guidance with respect to the Company’s operations and interests. The Board believes that it is important for directors to represent diverse viewpoints and professional backgrounds and experiences and, further, that the personal backgrounds and qualifications of the directors, considered as a group, should provide a composite mix of experience, knowledge and abilities. Consistent with the Stockholders Agreement, Messrs. Dickson, Goldberg, Triedman, Vollmer, and Wentzell have been designated as director nominees by Sponsor Stockholder (as defined below).

  24. Process for Stockholders to Recommend Director Nominees

    Process for Stockholders to Recommend Director Nominees The Nominating and Governance Committee will consider the recommendations of stockholders regarding potential director candidates. All candidates are reviewed in the same manner, regardless of the source of the recommendation. Stockholders who wish to recommend individuals for consideration by the Nominating and Governance Committee must do so by sending a written recommendation to the Committee c/o Amentum Holdings, Inc., 4800 Westfields Boulevard, Suite 400, Chantilly, VA 20151. The submission must set forth: • the name and address of the stockholder on whose behalf the submission is made; the number and class of shares of the Company that are owned beneficially by such stockholder as of the date of the submission; the name and address of the proposed candidate; and • the resume of the proposed candidate. Nominations must be received not fewer than 90 days nor more than 120 days prior to the first anniversary of the preceding year’s annual meeting. Our amended and restated bylaws also set forth the requirements for direct nomination of an individual by a stockholder for election to the Board.

  25. Director Compensation

    Director Compensation In April 2025, following a presentation on director compensation by Farient, the Compensation Committee approved director compensation for fiscal year 2025. Director compensation includes the following:

  26. Director Compensation

    | Component | Amount ($) | | Board Cash Retainer1 | $125,000 | | Equity Award2 | 190,000 | | Lead Independent Director Additional Retainer | 100,000 | | Committee Chair Additional Retainer | 25,000 |

  27. Director Compensation

    1 Non-employee directors will each also receive an additional fee of $2,000 for attending each meeting of the full Board of Directors or a standing committee that is in excess of eight meetings for the fiscal year and for each meeting of a special committee that is in excess of two meetings for the fiscal year. For Messrs. Dickson, Goldberg, Triedman, and Wentzell, cash amounts will be paid to their respective employers. 2 The number of restricted stock units (“RSUs”) granted were calculated by dividing the dollar value by the closing price of Amentum common stock on the date of grant. RSUs earn dividend equivalents and will vest on the date of the 2026 annual meeting of stockholders. For Messrs. Dickson, Goldberg, Triedman, and Wentzell, in lieu of RSU grants, an equivalent amount in cash will be paid to their respective employers. The equity awards are granted in the form of restricted stock units under our 2024 Stock Incentive Plan (the “Stock Incentive Plan”). Generally, these grants will occur following our annual meeting of stockholders. The cash retainer and any additional payments are generally paid in cash on a quarterly basis in arrears. Deferred Compensation Plan for Non-Employee Directors On December 5, 2024, our Board adopted the Amentum Holdings, Inc. Director Deferral Plan, an unfunded, non-qualified deferred compensation plan for the benefit of our non-employee directors, which became effective on December 5, 2024. Under this plan, each non-employee director of the Company who receives equity awards may elect in advance to defer all or a portion of cash retainer fees to be earned, and of direct equity awards to be granted, in the next calendar year or in subsequent years (special rules govern the timing of deferral election by new non-employee directors who join our Board after a calendar year has commenced). A director may elect to receive deferred cash fees and equity awards on the earlier of a future date selected by the director, a director’s separation from service (for any reason), disability, or death, or a Change in Control of Amentum Holdings, Inc. A director may elect to receive deferred amounts either in a lump sum or installments. Fiscal Year 2025 Non-Employee Director Compensation Table

  28. Director Compensation

    | Name | Fees earned or paid in cash ($)1 | Stock Awards ($)2 | Total ($) | | General Vincent K. Brooks | $125,000 | $189,997 | $314,997 | | Benjamin Dickson | 415,000 | — | 415,000 | | General Ralph E. Eberhart | 125,000 | 189,997 | 314,997 | | Alan E. Goldberg | 315,000 | — | 315,000 | | S. Leslie Ireland | 125,000 | 189,997 | 314,997 | | Barbara L. Loughran | 150,000 | 189,997 | 339,997 | | Sandra E. Rowland | 150,000 | 189,997 | 339,997 | | Christopher M.T. Thompson | 125,000 | 189,997 | 314,997 | | Russell Triedman | 340,000 | — | 340,000 | | John Vollmer | 125,000 | 189,997 | 314,997 | | Connor Wentzell | 315,000 | — | 315,000 |

  29. Director Compensation

    1 Represents fees earned during fiscal year 2025. For Messrs. Dickson, Goldberg, Triedman, and Wentzell, cash fees were paid to their respective employers and the amount above includes $190,000 of cash fees in lieu of equity. The table shows the total amount of cash fees that were earned by Ms. Ireland during fiscal year 2025, although she deferred payment of $93,750 of such fees. 2 This column reflects the aggregate grant date fair value of the restricted stock units and is measured based on the closing price of the Company’s common stock on the date of grant. The aggregate number of RSUs outstanding as of October 3, 2025, for each non-employee director who received equity awards (Messrs. Brooks, Eberhart, Thompson and Vollmer and Mses. Ireland, Loughran and Rowland) was 11,564.

  30. Pay versus Performance Highlights

    Pay versus Performance Highlights • In Fiscal Year 2025, a significant portion of CEO and Senior Executive compensation was linked to performance metrics that directly contribute to shareholder value. • Amentum’s Fiscal Year 2025 Short-term Incentive Plan yielded a company payout of 113% of the target, demonstrating strong financial discipline. • Amentum exceeded adjusted EBITDA and Net Debt Reduction, financial targets in Fiscal Year 2025. • Compensation programs were structured to align with the long-term interests of shareholders, ensuring executive rewards reflect company performance. • The Fiscal Year 2025 — Fiscal Year 2027 Long-term Incentive Plan, our first grant of performance share units, referred to as PSUs, includes targets for cumulative EBITDA and cumulative Free Cash Flow Performance (FCP), aligning executive incentives with ongoing financial health and shareholder value creation.

  31. Compensation Tables and Disclosures

    | Name and Principal Position | Fiscal Year1 | Salary ($) | Bonus ($)2 | Stock Awards ($)3 | Option Awards ($)4 | Non-Equity Incentive Plan Compensation ($)5 | Change in Pension Value and Nonqualified Deferred Compensation Earnings ($) | All Other Compensation ($)6 | Total ($) | | John Heller Chief Executive Officer | 2025 | $1,224,038 | $— | $10,651,567 | $7,332,048 | $1,937,518 | $— | $52,193 | $21,197,364 | | | 2024 | 1,165,385 | — | — | — | 1,586,384 | — | 30,710 | 2,782,479 | | Steven J. Demetriou Executive Chairman | 2025 | 1,250,000 | — | 2,499,973 | — | 1,412,500 | — | 25,019 | 5,187,492 | | | 2024 | 1,250,000 | — | 2,750,001 | — | 1,306,422 | — | 44,962 | 5,351,385 | | Travis B. Johnson Chief Financial Officer | 2025 | 647,308 | 500,000 | 2,749,979 | — | 733,634 | — | 53,254 | 4,684,175 | | | 2024 | 571,923 | 500,000 | — | — | 858,781 | — | 32,945 | 1,963,649 | | Stephen A. Arnette Chief Operating Officer | 2025 | 744,231 | — | 2,849,948 | — | 845,644 | — | 26,437 | 4,466,260 | | | 2024 | 586,154 | — | 1,500,013 | — | 511,203 | — | 61,602 | 2,658,972 | | Sean Mullen Chief Growth Officer | 2025 | 472,107 | 500,000 | 1,499,957 | — | 400,656 | — | 25,182 | 2,897,902 | | | 2024 | 443,300 | 350,000 | — | — | 416,061 | — | 24,603 | 1,233,964 |

  32. Outstanding Equity Awards at Fiscal Year-End Table

    Outstanding Equity Awards at Fiscal Year-End Table The table below shows the outstanding equity awards held by the NEOs as of the end of the fiscal year; the market value per share is based on the closing price of our stock on October 3, 2025 which was $25.95.

  33. Outstanding Equity Awards at Fiscal Year-End Table

    | | | Option Awards | | | | Stock Awards | | | | | Name | Grant Date | Number of Securities Underlying Unexercised Options(1) | | Option Exercise Price ($) | Option Expiration Date | Number of Shares or Units of Stock That Have Not Vested (#) | Market Value of Shares or Units of Stock That Have Not Vested ($) | 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 ($) | | | | Exercisable (#) | Unexercisable (#) | | | | | | | | John Heller | | | | | | | | | | | | 11/06/2024 | — | — | — | — | 118,8532 | $3,084,235 | 118,8533 | $3,084,235 | | | 11/06/20244 | — | — | — | — | 36,291 | 941,751 | — | — | | | 1/28/2025 | — | 1,373,9554 | $22.71 | 1/28/2029 | 155,938 | 4,046,591 | — | — | | Steven J. Demetriou5 | | | | | | | | | | | | 9/27/20246 | — | — | — | — | 43,396 | 1,126,126 | — | — | | | 11/06/20247 | — | — | — | — | 90,727 | 2,354,366 | — | — | | Travis B. Johnson | | | | | | | | | | | | 11/06/2024 | — | — | — | — | 36,2912 | 941,751 | 36,2913 | 941,751 | | | 11/06/20244 | — | — | — | — | 27,218 | 706,307 | — | — | | Stephen A. Arnette5 | | | | | | | | | | | | 9/27/20246 | — | — | — | — | 1,178 | 30,569 | — | — | | | 9/27/20248 | — | — | — | — | 2,808 | 72,868 | — | — | | | 9/27/20249 | — | — | — | — | 18,383 | 477,039 | — | — | | | 9/27/202410 | — | — | — | — | 38,652 | 1,003,019 | — | — | | | 11/6/2024 | — | — | — | — | 38,1052 | 988,825 | 38,1053 | 988,825 | | | 11/6/20244 | — | — | — | — | 27,218 | 706,307 | — | — | | Sean Mullen | | | | | | | | | | | | 11/06/2024 | — | — | — | — | 14,5162 | 376,690 | 14,5163 | 376,690 | | | 11/06/20244 | — | — | — | — | 18,145 | 470,863 | — | — | | | 12/20/202511 | — | — | — | — | 9,298 | 241,283 | — | — |

  34. Outstanding Equity Awards at Fiscal Year-End Table

    1 Mr. Heller’s stock options have a total term of 4 years from the date of grant. The shares of Common Stock subject to the option will vest in three substantially equal annual installments on the first three anniversaries of the grant date. 2 One-third of the RSUs will vest on each of the first, second and third anniversaries of the date of grant. 3 The PSUs vest upon achievement of three-year (2025-2027) cumulative Free Cash Flow and three-year cumulative Adjusted EBITDA targets. The PSUs are described more fully under “Compensation Discussion and Analysis—Compensation Elements—Annual Cash Incentive. 4 One-half of the RSUs shall vest on the 18 month and three-year anniversaries of the date of grant. 5 The equity grants on 9/27/2024 for Messrs. Demetriou and Arnette are Jacob’s equity grants that converted to Amentum shares upon close of the Transaction. 6 The RSUs will vest in full on November 17, 2025. 7 The RSUs will vest in full on November 6, 2025. 8 The RSUs will vest in full on March 2, 2026. 9 The RSUs will vest on each of November 16, 2025, and November 16, 2026. 10 The RSUs will vest on each of November 15, 2025, November 15, 2026, and November 15, 2027. The RSUs will vest in full on December 17, 2025. Option Exercises and Stock Vested Table The table below provides information on vesting of the restricted stock units and exercise of the stock options of each of our named executive officers during fiscal year 2025:

  35. Outstanding Equity Awards at Fiscal Year-End Table

    | | Option Awards | | Stock Awards | | | Name | Number of Shares Acquired on Exercise (#) | Value Realized on Exercise ($) | Number of Shares Acquired on Vesting (#) | Value Realized on Vesting ($) | | John Heller | — | — | — | — | | Steven J. Demetriou | — | — | — | — | | Travis B. Johnson | — | — | — | — | | Stephen A. Arnette1 | — | — | 1,751 | 33,905 | | Sean Mullen | — | — | — | — |

  36. Outstanding Equity Awards at Fiscal Year-End Table

    1 Mr. Arnette’s award includes Jacobs RSUs that were converted to Amentum RSUs upon Transaction and vested and settled in accordance with their original grant terms. Nonqualified Deferred Compensation The table below provides information regarding participation of each of our named executive officers in deferred compensation plans during fiscal year 2025:

  37. Outstanding Equity Awards at Fiscal Year-End Table

    | Name | Executive Contributions During Last Fiscal Year ($) | Aggregate Earnings During Last Fiscal Year ($) | Aggregate Withdrawals/ Distributions During Last Fiscal Year ($) | Aggregate Balance at Last Fiscal Year End ($) | | John Heller | $— | $— | $— | $— | | Steven J. Demetriou1 | — | — | — | — | | Travis B. Johnson | — | — | — | — | | Stephen A. Arnette | — | — | — | — | | Sean Mullen | — | — | — | — |

  38. Outstanding Equity Awards at Fiscal Year-End Table

    1 In September 2025, Mr. Demetriou’s balance in the Jacobs Executive Deferral Plan was transferred to the Jacobs Technology Executive Deferral Plan, a mirror plan established pursuant to the terms of the Employee Matters Agreement in connection with the Transaction that was assumed by Amentum in connection with the Transaction. Potential Payments upon Termination or a Change in Control The following table provides the estimated payments and benefits that each named executive officer would be entitled to receive upon termination of employment or in connection with a change-of-control of Amentum. The amounts set forth below assume that the triggering event occurred on October 3, 2025. Additionally, the below table reflects newly approved employment agreements and/or other related agreements, including the Severance Plan for Key Employees. In addition to the amounts set forth below, upon any termination of employment each officer would also be entitled to receive: • payments generally provided to salaried employees on a non-discriminatory basis upon termination, such as accrued salary, life insurance proceeds (for any termination caused by death), unused vacation, and 401(k) Plan distributions; accrued, vested balances under the defined contribution retirement plan, including vested employer contributions.

  39. Outstanding Equity Awards at Fiscal Year-End Table

    | Name | Cash Severance ($) | Prorated Bonus ($) | Benefit Continuation ($)1 | Long Term Disability ($)2 | Outplacement Services ($)3 | Equity With Accelerated Vesting ($)4 | Total ($) | | John Heller | | | | | | | | | Death5 | $— | $1,937,518 | $— | $— | $— | $12,524,192 | $14,461,710 | | Disability6 | — | 1,937,518 | — | 300,000 | — | 12,524,192 | 14,761,710 | | Retirement | — | 1,937,518 | — | — | — | 12,524,192 | 14,461,710 | | Change-in-Control | — | — | — | — | — | — | — | | Qualifying Termination On or After Change-In-Control | 5,174,486 | 1,937,518 | 378,001 | — | 15,000 | 15,608,427 | 23,113,432 | | Involuntary Termination | 3,880,865 | 1,937,518 | 363,705 | — | 15,000 | — | 6,197,088 | | Voluntary Resignation | — | — | — | — | — | — | — | | Termination for Cause | — | — | — | — | — | — | — | | Steven J. Demetriou | | | | | | | | | Death5 | — | 1,412,500 | — | — | — | 3,480,492 | 4,892,992 | | Disability6 | — | 1,412,500 | — | 300,000 | — | 3,480,492 | 5,192,992 | | Retirement | — | 1,412,500 | — | — | — | 3,480,492 | 4,892,992 | | Change-in-Control | — | — | — | — | — | 3,480,492 | 3,480,492 | | Qualifying Termination On or After Change-In-Control | 5,000,000 | 1,412,500 | 51,249 | — | 15,000 | 3,480,492 | 9,959,241 | | Involuntary Termination | 3,750,000 | 1,412,500 | 42,372 | — | 15,000 | 2,354,366 | 7,574,238 | | Voluntary Resignation | — | — | — | — | — | — | — | | Termination for Cause | — | — | — | — | — | — | — | | Travis B. Johnson | | | | | | | | | Death5 | — | 733,634 | — | | — | 1,648,059 | 2,381,693 | | Disability6 | — | 733,634 | — | 300,000 | — | 1,648,059 | 2,681,693 | | Retirement | — | 733,634 | — | — | — | 1,648,059 | 2,381,693 | | Change-in-Control | — | — | — | — | — | — | — | | Qualifying Termination On or After Change-In-Control | 2,237,978 | 733,634 | 143,036 | — | 15,000 | 2,589,810 | 5,719,458 | | Involuntary Termination | 2,237,978 | 733,634 | 143,036 | — | 15,000 | — | 3,129,648 | | Voluntary Resignation | — | — | — | — | — | — | — | | Termination for Cause | — | — | — | — | — | — | — | | Stephen A. Arnette | | | | | | | | | Death5 | — | 845,644 | — | | — | 3,278,627 | 4,124,271 | | Disability6 | — | 845,644 | — | 300,000 | — | 3,278,627 | 4,424,271 | | Retirement | — | 845,644 | — | — | — | 3,278,627 | 4,124,271 | | Change-in-Control | — | — | — | — | — | 4,267,452 | 4,267,452 | | Qualifying Termination On or After Change-In-Control | 2,247,536 | 845,644 | 72,981 | — | 15,000 | 4,267,452 | 7,448,613 | | Involuntary Termination | 2,247,536 | 845,644 | 72,981 | — | 15,000 | — | 3,181,161 | | Voluntary Resignation | — | — | — | — | — | — | — | | Termination for Cause | — | — | — | — | — | — | — | | Sean Mullen | | | | | | | | | Death5 | — | 400,656 | — | | — | 1,088,836 | 1,489,492 | | Disability6 | — | 400,656 | — | 283,800 | — | 1,088,836 | 1,773,292 | | Retirement | — | 400,656 | — | — | — | 1,088,836 | 1,489,492 | | Change-in-Control | 2,000,000 | — | — | — | — | — | 2,000,000 | | Qualifying Termination On or After Change-In-Control | 898,583 | 400,656 | 231,739 | — | 15,000 | 1,465,526 | 3,011,504 | | Involuntary Termination | 898,583 | 400,656 | 231,739 | 15,000 | — | 1,545,978 | | | Voluntary Resignation | — | — | — | — | — | — | — | | Termination for Cause | — | — | — | — | — | — | — |

  40. Outstanding Equity Awards at Fiscal Year-End Table

    The value for financial planning was based on a $10,000 assumption. Long-Term Disability insurance payments cover up to 60% of base salary with a maximum benefit of $25,000 per month ($300,000 per year). 3 The value for outplacement services was based on a $15,000 assumption. 4 For equity calculations, we have used closing stock price on October 3, 2025 of $25.95. 5 Each NEO is entitled to receive a pro rata bonus upon termination for death, based on actual performance, that is payable in a lump sum. In the event of a termination due to retirement, the STIP provides that a pro rata bonus may be considered and requires approval of the CEO, and we have included a pro rata bonus amount for each NEO. Options and RSUs will accelerate and vest in full upon termination and PSUs will remain outstanding and will vest based on actual performance at the end of the performance period (the amount in the table reflects the value of the accelerated options and RSUs). 6 Each NEO is entitled to receive a pro rata bonus upon termination for disability, based on actual performance, that is payable in a lump sum, as well as the Long-Term Disability insurance payments described in Note 2 above. Options and RSUs will accelerate and vest in full upon termination and PSUs will remain outstanding and will vest based on actual performance at the end of the performance period (the amount in the table reflects the value of the accelerated options and RSUs. 7 Please see the discussion below in “Amentum Severance Plan for Key Employees” that describes the payments and benefits provided to the NEOs in the event of a qualifying involuntary termination during the period 3 months prior to a change in control and ending on the date that is 24 months following a change in control (as defined in the Severance Plan). 8 In the event of an involuntary termination that does not occur in connection with a change in control, please see the discussion below in (i) “Severance upon Termination without Cause or for Good Reason” for a description of the payments and benefits provided to Messrs. Heller, Johnson and Arnette, and (ii) “Amentum Severance Plan for Key Employees” for a description of the payments and benefits provided to Mr. Mullen.

  41. CEO Pay Ratio

    CEO Pay Ratio As required by Item 402(u) of Regulation S-K, we compared the annual total compensation of our Chief Executive Officer (“CEO”) to that of our median employee (excluding the CEO) for fiscal year 2025. The ratio reflects a reasonable estimate calculated in a manner consistent with item 402(u) of Regulation S-K under the Exchange Act. We identified the median employee based on actual cash compensation paid (wages, overtime, and cash incentives) to employees as of October 3, 2025. Our employee population used for determining the median employee was approximately 47,600, consisting of approximately 34,000 employees based in the United States and approximately 13,600 employees based outside of the United States, inclusive of unionized employees and those covered by The McNamara-O’Hara Service Contract Act (SCA). Annualized compensation was selected as the appropriate measure because it was a reasonable reflection of annual compensation. For fiscal year 2025, the annual compensation of our median employee was $83,741 and the annual total compensation for our CEO was $21,197,364, as outlined in the “Summary Compensation Table” above. Accordingly, the CEO Pay Ratio for fiscal year 2025 was 253:1. In addition, we have calculated an alternative pay ratio using and adjusted amount of total compensation for Mr. Heller that removes the one-time make-whole equity award of stock options and time-based restricted shares described above under “Compensation Discussion & Analysis — One-Time Awards”.1 When calculated in this manner, Mr. Heller’s adjusted annual total compensation for fiscal year 2025 was $10,763,709 and the ratio to our median employee was approximately 129:1.

  42. Pay Versus Performance

    Pay Versus Performance As required by Section 953(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act, and Item 402(v) of Regulation S-K under the Securities Act, we are providing the following information about the relationship between “Compensation Actually Paid” (herein referred to as “CAP”) to our CEO and our other NEOs as compared to the Company’s GAAP Net Income and our Company-selected performance measure, Adjusted EBITDA. For further information concerning Amentum’s performance-based approach to executive compensation and how Amentum aligns executive compensation with company performance, refer to the CD&A of this proxy statement. The CEO’s fiscal year 2025 total compensation as outlined in the Summary Comp Table (SCT) includes a one-time make-whole equity award. This is a nonrecurring award with details outlined under the One-Time Awards section page 49 of this CD&A. 2025 Pay vs. Performance Table

  43. Pay Versus Performance

    | Year | Summary Compensation Table Total for CEO1 | Compensation Actually paid to CEO3 | Average Summary Compensation Table Total for Other NEOs2 | Average Compensation Actually Paid to Other NEOs2,3 | Value of Initial Fixed $100 Investment Based On: | | Net Income (in $M)5 | Adjusted EBITDA (in $M)6 | | | | | | | Amentum TSR4 | Peer Group TSR4 | | | | 2025 | $21,197,364 | $30,949,734 | $4,308,958 | $4,364,876 | $90 | $101 | $66 | $1,104 | | 2024 | 2,732,479 | 2,782,479 | 2,801,993 | 2,801,933 | — | — | (82) | 1,052 |

  44. Pay Versus Performance

    1 Mr. Heller was the CEO in fiscal year 2024. He did not receive any equity awards in 2024. 2 Messrs. Demetriou, Arnette, Johnson and Mullen were the non-CEO named executive officers for fiscal years 2025 and 2024 3 Amounts in this column represent the Summary Compensation Total plus the fair value of equity awards at year-end for awards granted in the year, the change in fair value of equity awards at year-end (from the end of the prior year) for equity awards granted in previous years, the fair value of equity awards on the vest date for equity awards which were granted and vested in the year, and the change in fair value of equity awards at year-end (from the vest date) for equity awards which vested in the year, as applicable. For a reconciliation, see the table below. 4 Cumulative TSR is measured as of a beginning date of September 30, 2024; and peer group TSR reflects values for the S&P SPCM Professional Services Index. Both Amentum’s TSR and peer group TSR are calculated in accordance with Item 201(e) of Regulation S-K. 5 Based on net income, determined in accordance with generally accepted accounting principles, as shown in our financial statements. 6 Adjusted EBITDA and Pro Forma Adjusted EBITDA are the Company-selected measures for fiscal years 2025 and 2024, respectively, for purposes of this table.

  45. Pay Versus Performance

    | Item and Value Added (Deducted) | Fiscal Year 2025 | | For CEO: | | | Summary Compensation Table Total | $21,197,364 | | - Summary Compensation Table “Option Awards” column value | 7,332,048 | | - Summary Compensation Table “Stock Awards” column value | 10,651,567 | | + year-end fair value of outstanding and unvested equity awards granted in the fiscal year | 27,735,985 | | +/- change in fair value of outstanding and unvested equity awards granted in prior years | — | | + vest date fair value of equity awards granted in the covered year | — | | +/- change in fair value of prior-year equity awards vested in the fiscal year | — | | Compensation Actually Paid | $30,949,734 |

  46. Pay Versus Performance

    | Item and Value Added (Deducted) | Fiscal Year 2025 | | For Non-CEO named executive officers: | | | Summary Compensation Table Total | $4,308,958 | | - Summary Compensation Table “Option Awards” column value | — | | - Summary Compensation Table “Stock Awards” column value | 2,399,964 | | + year-end fair value of outstanding and unvested equity awards granted in the fiscal year | 2,455,882 | | +/- change in fair value of outstanding and unvested equity awards granted in prior years | — | | + vest date fair value of equity awards granted in the covered year | — | | +/- change in fair value of prior-year equity awards vested in the fiscal year | — | | Compensation Actually Paid | $4,364,876 |

  47. Pay Versus Performance

    Relationship Between Compensation Actually Paid (CAP) and Performance Measures The Pay vs. Performance tables above illustrate that CAP to our CEO and average NEO has tracked with our TSR and financial performance because CAP values reflect changes in the value of executives’ outstanding equity holdings which fluctuate with changes in our stock price; additionally, CAP values reflect incentive payouts which fluctuate with our financial performance. In particular, the year-end value of awards granted in 2025 increased moderately relative to the grant date value because of the increase in our stock price. However, due to Amentum’s limited compensation and trading history, a longer-term pay versus performance trend is not yet available to disclose. Most Important Financial Measures The table below lists our most important performance measures used to link CAP to our NEOs to company performance over the fiscal year ending October 3, 2025. These measures are used to determine payouts for our annual and long-term incentive plans. For more information on our incentive plan measures and goals, refer to the CD&A of this proxy statement. The performance measures included in this table are not ranked by relative importance.

  48. Pay Versus Performance

    | Fiscal Year 2025 Most Important Financial Measures | | Adjusted EBITDA | | Days Sales Outstanding (DSO) | | Free Cash Flow (FCF) | | Net Debt Reduction |

  49. Pay Versus Performance

    COMPENSATION COMMITTEE REPORT The Compensation Committee has reviewed and discussed the Compensation Discussion & Analysis (“CD&A”) included in this proxy statement with members of management, and based on such review and discussions, the Compensation Committee recommended to the Board that the CD&A be included in this proxy statement. THE COMPENSATION COMMITTEE Russell Triedman (Chair) Benjamin Dickson General Ralph E. Eberhart S. Leslie Ireland AUDIT COMMITTEE REPORT The Audit Committee is composed of four directors identified below, each of whom is an independent director as defined by the applicable SEC rules and the NYSE listing standards. Two committee members, Barbara L. Loughran and Sandra E. Rowland, have been designated by the Board as “audit committee financial experts” under applicable SEC rules. For further description of each committee member’s background and expertise, please refer to the “Director Nominees” section of our proxy statement beginning on page 7. The Audit Committee is responsible for assisting the Board in fulfilling its oversight responsibilities relating to, among other things, the Company’s accounting, auditing, and financial reporting processes, internal controls, compliance with legal and regulatory requirements and its code of ethics, and risk management processes, as discussed more fully in the Audit Committee charter, a copy of which is available on our website, www.amentum.com. In accordance with its charter, the Audit Committee appoints the Company’s independent registered public accounting firm, EY, subject to stockholder ratification, and conducts an annual review of its performance. In addition, the Audit Committee pre-approves all audit and permissible non-audit services provided by EY. The Audit Committee also oversees the Company’s internal audit function, including its annual audit plan, budget, and staffing. As part of its oversight role, the Audit Committee meets throughout the year, separately and together, with each of management, the Company’s internal auditors, and EY. Management has the primary responsibility for the Company’s financial statements and accounting and reporting processes, including the systems of internal accounting control. EY is responsible for performing an independent audit of the consolidated financial statements in accordance with the standards of the Public Company Accounting Oversight Board (“PCAOB”), and rendering opinions on whether the financial statements are in conformity with accounting principles generally accepted in the United States and, when required, the effectiveness of the Company’s internal control over financial reporting. The Audit Committee has reviewed and discussed with management of the Company and EY, the audited consolidated financial statements of the Company for the fiscal year ended October 3, 2025 (the “Audited Financial Statements”). The Audit Committee also reviewed any significant audit findings identified by EY, and those identified by the Company’s internal auditors as well as management’s responses thereto. In addition, the Audit Committee discussed with EY the matters required to be discussed by the applicable requirements of the PCAOB and the SEC. The Audit Committee has also: (i) considered whether non-audit services provided by EY are compatible with its independence; (ii) received the written disclosures and the letter from EY required by the applicable requirements of the PCAOB regarding EY’s communications with the Audit Committee concerning independence; and (iii) discussed with EY its independence. Based on the reviews and discussions described above, the Audit Committee recommended to the Board that the Audited Financial Statements be included in our Annual Report on Form 10-K for the fiscal year ended October 3, 2025 for filing with the SEC. THE AUDIT COMMITTEE Sandra E. Rowland (Chair) General Vincent K. Brooks S. Leslie Ireland Barbara L. Loughran PRE-APPROVAL OF SERVICES BY INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM The Audit Committee pre-approves all audit, audit-related, tax, and other services performed by our independent auditors. The Audit Committee pre-approves specific categories of services. Unless the type of service had previously been pre-approved, the Audit Committee must approve that specific service before the independent auditors may perform it. INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FEES The following table presents the fees for services performed by the principal accounting firm, EY, during fiscal years 2025 for Amentum Holdings, Inc. and 2024 for Amentum Holdings, Inc. (Amentum Parent Holdings LLC prior to the Transaction). Fiscal year 2025 audit fees included additional fees associated with audit and review procedures required as a public company and reflect certain non-recurring fees related to the Transaction and first year compliance with Sarbanes-Oxley (“SOX”).

  50. Pay Versus Performance

    | (Amounts in thousands) | Year Ended October 3, 2025 | Year Ended September 27, 2024 | | Audit fees1 | $10,250 | $6,959 | | Audit-related fees2 | 3,703 | 1,671 | | Tax fees3 | 569 | 617 | | All other fees4 | 8 | 51 | | Total5 | $14,530 | $9,298 |

  51. Pay Versus Performance

    1 “Audit fees” principally include those for services related to the audit and quarterly reviews of the Company’s consolidated financial statements and consultation on accounting matters. 2 These fees include fees for services that are normally provided in connection with the Company’s statutory and regulatory filings and fees incurred in connection with mergers, acquisitions and divestitures, including the Transaction. 3 “Tax fees” principally include domestic and foreign tax compliance and advisory services. 4 “All other fees” consist of fees not reported under the categories above. In fiscal year 2024, EY performed services for Jacobs that are not included in the amounts above. PROPOSAL 2: RATIFICATION OF APPOINTMENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM The Audit Committee has appointed EY as the independent auditors to perform an integrated audit of the Company for the fiscal year ending October 2, 2026. At the 2026 Annual Meeting, shareholders will be asked to ratify the appointment of EY. The Board believes that obtaining stockholder ratification of the appointment is a sound corporate governance practice. If the stockholders do not vote on an advisory basis in favor of EY, the Audit Committee will reconsider whether to hire the firm and may retain EY or hire another firm without resubmitting the matter for stockholders to approve. The Audit Committee retains the discretion at any time to appoint a different independent auditor. Representatives of EY are expected to be present at the Annual Meeting, available to respond to appropriate questions, and will have the opportunity to make a statement if they desire.

  52. Pay Versus Performance

    | The Board of Directors recommends a vote FOR ratification of the appointment of Ernst & Young LLP as the independent registered public accounting firm for the Company for fiscal year 2026. |

  53. Pay Versus Performance

    PROPOSAL 3: ADVISORY VOTE ON COMPANY’S EXECUTIVE COMPENSATION As required by Section 14A of the Exchange Act, the Company is providing stockholders with a non-binding advisory vote on the fiscal year 2025 compensation of our named executive officers, as disclosed in the CD&A, the accompanying compensation tables, and the related narrative disclosure in this proxy statement, commonly referred to as the “Say-on-Pay” vote. Although this vote is advisory, the Board and the Compensation Committee value the opinions of our stockholders and will review and consider the voting results when making future compensation decisions for our named executive officers. At the Company’s 2025 Annual Meeting of stockholders, the stockholders voted in favor of the Company conducting a say-on-pay vote each year at the Annual Meeting. In light of the vote at the 2025 Annual Meeting, the Company has determined that it will hold an annual advisory vote on the compensation of the Company’s named executive officers until the next required advisory vote on the frequency of such vote, which will occur no later than the Company’s Annual Meeting of Stockholders in 2031. You should read the CD&A and the compensation tables in determining whether to approve this proposal. The Board submits the following resolution for a stockholder vote at the 2026 Annual Meeting of Stockholders: RESOLVED, that the compensation paid to the Company’s named executive officers, as disclosed in the Company’s Proxy Statement for the 2026 Annual Meeting of Stockholders pursuant to Item 402 of Regulation S-K, including the executive compensation tables and the related narrative discussion, is hereby APPROVED.

  54. Pay Versus Performance

    | The Board of Directors recommends a vote FOR approval, on an advisory basis, of the compensation paid to our named executive officers in fiscal year 2025 as disclosed in this proxy statement. |

  55. Pay Versus Performance

    OTHER BUSINESS The Board is not aware of any other matters to be presented at the Annual Meeting. If any other matter proper for action at the meeting should be presented, the holders of the accompanying proxy will vote the shares represented by the proxy on such matter in accordance with their best judgment. If any matter not proper for action at the meeting should be presented, the holders of the proxy will vote against consideration of the matter or the proposed action. By order of the Board of Directors, Michele T. St. Mary Chief Legal Officer, General Counsel & Corporate Secretary Chantilly, Virginia IMPORTANT INFORMATION ABOUT ANNUAL MEETING AND PROXY PROCEDURES The Board is soliciting proxies to be used at the Annual Meeting of Stockholders to be held virtually on February 6, 2026, beginning at 9:00 a.m. (EST) at www.virtualshareholdermeeting.com/AMTM2026.