eose-20260330

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant ☒

Filed by a party other than the Registrant ☐

Check the appropriate box:

☒ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☐ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material Under §240.14a-12

EOS ENERGY ENTERPRISES, INC.

(Exact Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☒ No fee required.

☐ Fee paid previously with preliminary materials.

☐ Fee computed on table in exhibit required by Item 25 (b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

PRELIMINARY PROXY STATEMENT — SUBJECT TO COMPLETION — DATED MARCH 30, 2026

Notice of Annual Meeting of Stockholders

to be held on June 3, 2026

To the Stockholders of Eos Energy Enterprises, Inc.:

NOTICE IS HEREBY GIVEN that the Annual Meeting of Stockholders (the “Annual Meeting”) of Eos Energy Enterprises, Inc., a Delaware corporation (the “Company”), will be a virtual meeting conducted exclusively via live webcast at www.virtualshareholdermeeting.com/EOSE2026 on June 3, 2026, at 10:00 a.m. Eastern time for the following purposes:

Meeting Date

June 3, 2026

Proposals

Voting Recommendation

Page Reference

to elect three directors as Class III directors of Eos Energy Enterprises, Inc., each to serve for three years and until his successor has been elected and qualified, or until his earlier death, resignation or removal;

"FOR"

Meeting Time

10:00 a.m. Eastern time

to ratify the selection of Deloitte & Touche LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026;

"FOR"

to approve a non-binding advisory resolution approving the compensation of the named executive officers;

"FOR"

to approve an amendment to our Third Amended and Restated Certificate of Incorporation to increase the number of shares of authorized common stock of the Company from 600,000,000 to 800,000,000; and

"FOR"

to approve an amendment to our Second Amended and Restated 2020 Incentive Plan.

"FOR"

Meeting Place

Live webcast at www.virtualshareholdermeeting.com/EOSE2026

The Company will also transact such other business as may properly come before the Annual Meeting or any adjournment or postponement thereof.

The foregoing items of business are more fully described in the Proxy Statement accompanying this Notice of Annual Meeting of Stockholders. Only stockholders who owned common stock of the Company at the close of business on April 13, 2026 (the “Record Date”) can vote at this meeting or any adjournments that take place. The Company will begin mailing the Notice of Internet Availability to our stockholders of record as of the Record Date for the first time on or about April 14, 2026.

Eos Energy Enterprises

2026 Virtual Annual Stockholder Meeting

The Board of Directors has determined to hold the annual meeting virtually in order to facilitate stockholder attendance and participation by stockholders from all locations at no cost. We believe this is the right choice for the Company, as it enables engagement with our stockholders, regardless of size, resources, or physical location. We are committed to ensuring that stockholders will be afforded the same rights and opportunities to participate as they would at an in-person meeting. You will be able to attend the meeting online, vote your shares electronically and submit questions during the meeting by visiting www.virtualshareholdermeeting.com/EOSE2026 at the meeting date and time. The meeting webcast will begin promptly at 10:00 a.m. Eastern Time. We encourage you to access the meeting prior to the start time. Online check-in will begin at 9:45 a.m. Eastern Time, and you should allow ample time for the check-in procedures. If you experience technical difficulties during the check-in process or during the meeting, please call the technical support number that will be posted on the virtual Annual Meeting login page for assistance. Technical assistance will be available through the conclusion of the Annual Meeting.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON JUNE 3, 2026

The Notice of Annual Meeting of Stockholders to be held on June 3, 2026, the accompanying Proxy Statement and the Company’s 2025 Annual Report on Form 10-K are available, free of charge, at http://www.proxyvote.com.

The Notice contains instructions on how to access our proxy materials and vote over the internet at www.proxyvote.com and how stockholders can receive a paper copy of our proxy materials, including the accompanying Proxy Statement, a proxy card or voting instruction card and our fiscal year ended December 31, 2025 Annual Report on Form 10-K. Stockholders can also request to receive future proxy materials in printed form by mail or electronically by email by contacting the Investor Relations Department at 862-207-7955 or email ir@eose.com.

By Order of the Board of Directors,

/s/Michael Silberman

Michael Silberman

Chief Legal Officer and Corporate Secretary

March 30, 2026

Your vote is important.

Whether or not you plan to attend the virtual meeting online, we encourage you to read the accompanying proxy statement and our annual report on Form 10-K for the fiscal year ended December 31, 2025, and submit your proxy as soon as possible using one of the three convenient voting methods described in “Information About the Proxy Process and Voting” in the proxy statement. If you receive more than one set of proxy materials or notice of internet availability because your shares are registered in different names or addresses, each proxy should be signed and submitted to ensure that all of your shares will be voted.

2026 Proxy Statement

iii


Table of Contents

Proposal No. 1

Election of Directors

Director Compensation Table

Executive Compensation

Certain Relationships and Related Person Transactions

Information About the Proxy Process and Voting

Continuing Directors

Proposal No. 2

Ratification of Selection of Independent Registered Public Accounting Firm

Proposal No. 3

Advisory Vote to Approve Our Named Executive Compensation

Security Ownership of Certain Beneficial Owners and Management

Appendix A

Third Certificate of Amendment to the Third Amended and Restated Certificate of Incorporation

Corporate Governance

Report of the Audit Committee of the Board of Directors

Proposal No. 4

Authorized Share Amendment

Delinquent Section 16(a) Reports

Appendix B

Second Amendment to the Second Amended and Restated 2020 Incentive Pla n

Stockholder Engagement

Executive Officers

Proposal No. 5

Amendment to the Second Amended and Restated 2020 Incentive Plan

Additional Information

Appendix C

Second Amended and Restated 2020 Incentive Plan

Stockholder Engagement


Proxy Statement For the 2026 Annual Meeting of Stockholders June 3, 2026

Eos Energy Enterprises, Inc.

3920 Park Avenue

Edison, New Jersey 08820

We have made available our proxy materials because the Board of Directors (the “Board”) of Eos Energy Enterprises, Inc. (referred to herein as the “Company,” “Eos,” “we,” “us” or “our”) is soliciting your proxy to vote at our 2026 Annual Meeting of Stockholders (the “Annual Meeting”) to be held on June 3, 2026, at 10:00 a.m. Eastern Time, at www.virtualshareholdermeeting.com/EOSE2026.

•This Proxy Statement summarizes information about the proposals to be considered at the Annual Meeting and other information you may find useful in determining how to vote.

•The Proxy Card is the means by which you actually authorize another person to vote your shares in accordance with your instructions.

In addition to solicitations by mail, our directors, officers and employees, without additional remuneration, may solicit proxies by telephone, e-mail and personal interviews. All costs of solicitation of proxies will be borne by us. Brokers, custodians and fiduciaries will be requested to forward proxy soliciting material to the owners of stock held in their names, and we will reimburse them for their reasonable out-of-pocket expenses incurred in connection with the distribution of proxy materials.

Pursuant to the rules adopted by the Securities and Exchange Commission (the “SEC”), we have elected to provide access to our Annual Meeting materials, which include this Proxy Statement and our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “Form 10-K”), over the internet in lieu of mailing printed copies. The Company will begin mailing the Notice of Internet Availability to our stockholders of record as of the Record Date for the first time on or about April 14 , 2026.

The Notice of Internet Availability will contain instructions on how to access and review the Annual Meeting materials and will also contain instructions on how to request a printed copy of the Annual Meeting materials. Additionally, we have provided brokers, dealers, banks, voting trustees and their nominees, at our expense, with additional copies of our proxy materials and our Annual Report on Form 10-K so that they can supply these materials to the beneficial owners of shares of our common stock as of the Record Date. Our Annual Report on Form 10-K and the 2026 Proxy Statement are available, free of charge, at proxyvote.com.

Table of Contents

Proxy Summary

Meeting

Information

Meeting Date

June 3, 2026

Meeting Time

10:00 a.m. Eastern time

Proposals

Voting Recommendation

Page Reference

Meeting Place

Live webcast at www.virtualshareholdermeeting.com/EOSE2026

"FOR"

to ratify the selection of Deloitte & Touche LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026;

"FOR"

to approve a non-binding advisory resolution approving the compensation of the named executive officers;

"FOR"

Voting

Information

to approve an amendment to our Third Amended and Restated Certificate of Incorporation to increase the number of shares of authorized common stock of the Company from 600,000,000 to 800,000,000; and

"FOR"

to approve an amendment to our Second Amended and Restated 2020 Incentive Plan.

"FOR"

Vote by Internet

www.proxyvote.com

Director Nominees

Vote by Telephone

1-800-690-6903

Name

Age

Director

since

Independent

Primary Occupation

Other Public Boards

Vote by Mail

Vote Processing

c/o Broadridge

51 Mercedes Way

Edgewood, NY 11717

Jeff Bornstein

2022

Yes

Founder, Principal and Co-Managing Partner,

Whipstick Ventures LLC

AlloVir, Inc.

Claude Demby

2021

Yes

Former President,

Cree LED

Piedmont Lithium Inc.

Nathaniel Fick

2026

Yes

Chief Strategy Officer for Equities and Senior Managing Director, Cerberus Capital Florida, LLC

–

Vote In-Person

www.virtualshareholdermeeting.com/EOSE2026

Eos Energy Enterprises


Proxy Summary			Table of Contents

Director Skills and Qualifications

Skill and Definition

Jeff
Bornstein

Claude
Demby

Alex
Dimitrief

Nathaniel
Fick

Joe
Mastrangelo

Jeff
McNeil

Joseph
Nigro

Greg
Nixon

Nick
Robinson

David
Urban

Mimi
Walters

Public Company Leadership Experience

Energy Market Expertise

Manufacturing Expertise

Disruptive Technology Experience

Capital Markets Expertise

Government/Regulatory Experience

Human Capital/Talent Management

Enterprise Risk Management

Sustainability and Environmental


2			Eos Energy Enterprises


Table of Contents


Proposal No. 1 Election of Class III Directors

3 board classes

1 class elected each year

Our Board is divided into three (3) classes with only one class of directors being elected in each year and each class serving a three (3) year term. The directors hold their office for a term of three (3) years or until their respective successors are elected and qualified, subject to such director’s earlier death, resignation, disqualification or removal. Class I directors are Marian “Mimi” Walters and Jeffrey McNeil; Class II directors are Joe Mastrangelo, our CEO, Alex Dimitrief, and Joseph Nigro, the Chair of our Board; and Class III directors are Jeff Bornstein, Claude Demby, and Nathaniel Fick.

As further described below, the holders of the Series B-1 Convertible Preferred Stock, par value $0.0001 per share (the “Series B-1 Preferred Stock”), Series B-2 Convertible Preferred Stock, par value $0.0001 per share (the “Series B-2 Preferred Stock”), Series B-3 Convertible Preferred Stock, par value $0.0001 per share (the “Series B-3 Preferred Stock”) and the Series B-4 Convertible Preferred Stock, par value $0.0001 per share (the “Series B-4 Preferred Stock,” and, collectively with the Series B-1 Preferred Stock, the Series B-2 Preferred Stock and the Series B-3 Preferred Stock, the “Preferred Stock”) have the right, exclusively and voting together as a separate class, to appoint up to three (3) persons to serve as directors on the Board (the “Preferred Directors”). The sole holder of the Preferred Stock has previously appointed Nick Robinson, Gregory Nixon, and David Urban to serve as Preferred Directors on the Board. The sole holder of the Preferred Stock has appointed Messrs. Robinson, Nixon and Urban as Preferred Directors, each to serve a term of one (1) year or until their respective successors are elected and qualified. Because the holders of the Preferred Stock have the exclusive right to appoint the Preferred Directors, the holders of our common stock are not entitled to vote to elect such persons. For additional information concerning Preferred Stock director election and nomination rights, see “Corporate Governance – Board Composition.”


Proposal No. 1			Table of Contents

Class III directors standing for re-election at the Annual Meeting are Jeff Bornstein, Claude Demby, and Nathaniel Fick. Class I and Class II directors will stand for election at the 2027 and 2028 annual meetings of stockholders, respectively.

Each of the nominees for election as a Class III director is currently a director. If elected at the Annual Meeting, each of the nominees for election as Class III directors would serve for three years and until his successor is duly elected and qualified, or until his earlier death, resignation or removal. If any nominee is unable or unwilling to be a candidate for election, the Board may appoint another nominee or reduce the size of the Board.

The following table sets forth information for the nominees who are currently standing for election:


Name	Age	Director Since
Jeff Bornstein(1)	60	2022
Claude Demby(2)	61	2021
Nathaniel Fick(3)	48	2026

1.Member of the Audit Committee and member of the Leadership Development & Compensation Committee.

2.Member of the Audit Committee and member of the Nominating and Corporate Governance Committee.

3.Member of the Nominating and Corporate Governance Committee.

Set forth below is biographical information for the nominees. The following includes certain information regarding the nominees’ individual experience, qualifications, attributes, and skills that led the Board to conclude that they should serve as a director.

Jeff Bornstein

Background

Mr. Bornstein has served as a member of our Board since 2022. Mr. Bornstein is the founder, principal and co-managing partner of Whipstick Ventures LLC, an investment company focused on early-stage companies with novel solutions across energy storage and efficiency, services, biotech, and fin-tech. He also serves as the managing partner of Generation Capital Partners. Prior to founding Whipstick Ventures in 2018, Mr. Bornstein held senior leadership roles at General Electric (GE) (NYSE: GE), including Vice Chairman and Chief Financial Officer from 2013 to 2017. He began his career at GE in 1989 through the GE Power Systems' Financial Management Program and served in a variety of finance leadership roles, including 12 years as Senior Vice President and Chief Financial Officer of GE Capital. Mr. Bornstein earned a Bachelor of Science from Northeastern University and currently serves as trustee of the university. He currently serves on the board of directors of AlloVir, Inc. (NASDAQ: ALVR), where he chairs the Audit Committee. He also serves on the board of Build On and is actively involved in several youth development programs.

Age: 60

Director since: 2022

Committees: Audit Committee (Chair), Leadership Development & Compensation Committee

Mr. Bornstein's qualifications to serve on our board of directors include his extensive finance background, executive leadership experience, and deep industry knowledge, particularly in the energy sector.


4			Eos Energy Enterprises


Table of Contents			Proposal No. 1

Claude Demby

Background

Mr. Demby has been a member of our Board since 2021. From 2018 to 2022, Mr. Demby served as President of Cree LED, a lighting and industrial innovation company. Prior to that, he was responsible for Mergers and Acquisitions at Cree, Inc. (Cree) and served as the Senior Vice President and General Manager of Cree’s Semiconductor Materials Business. Before joining Cree, Mr. Demby served as Chief Executive Officer and Director of Noel Group, an industrial holding company overseeing five global manufacturing businesses. Earlier in his career, he served as President and Chief Operating Officer of L&L Products, Inc., a global automotive and aerospace OEM focused on solutions for noise and vibration reduction while enhancing structural integrity. Mr. Demby’s career began in engineering roles at Proctor and Gamble and GE. Mr. Demby earned a Bachelor of Science from the University of Delaware and an MBA from Rensselaer Polytechnic Institute. He currently serves as director of the Brown Capital Management Mutual Fund Trust, where he chairs the Nominating and Governance Committee, and served on the board of Piedmont Lithium Incorporated (NASDAQ: PLL), a clean energy company, where he chaired Leadership and Compensation Committee and the Nominating and Governance Committee during his six-year tenure. He Previously served as a Director of the Federal Reserve Bank of Richmond's Charlotte branch including a period as Chairman from 2012 to 2017. Mr. Demby also served on the board of directors of the Raleigh Chamber of Commerce, including Chair-Elect and advisor, and is a founder and leader of Valour Academy Schools, Inc. in Raleigh, North Carolina.

Age: 61

Director since: 2021

Committees: Audit Committee, Nominating and Corporate Governance Committee

Mr. Demby’s qualifications to serve on our board of directors include his multi-dimensional fiduciary readiness and sector-specific operational expertise.

Nathaniel Fick

Background

Mr. Fick has been a member of our Board since 2026. Mr. Fick has served as Chief Strategy Officer for Equities at Cerberus Capital Management since 2025, where he oversees global investment activities across the firm’s Private Equity, Supply Chain, and Ventures platforms. Prior to joining Cerberus, Mr. Fick served as the U.S. Ambassador at Large for Cyberspace and Digital Policy at the State Department, leading American diplomatic efforts regarding cybersecurity, artificial intelligence, and digital infrastructure. His private sector experience includes serving as General Manager of Elastic Security following its 2019 acquisition of Endgame, a venture-backed cybersecurity firm where Mr. Fick served as Chief Executive Officer. Additionally, he spent nearly a decade as an Operating Partner at Bessemer Venture Partners. Mr. Fick began his career as an officer in the United States Marine Corps, leading infantry and reconnaissance units in Afghanistan and Iraq. He is the author of the New York Times bestseller One Bullet Away. Mr. Fick holds a B.A. from Dartmouth College, an M.P.P. from the Harvard Kennedy School, and an M.B.A. from the Harvard Business School. He currently serves as a Director of the Council on Foreign Relations and was formerly a Trustee of Dartmouth College.

Age: 48

Director since: 2026

Committees: Nominating and Corporate Governance Committee

Mr. Fick’s qualifications to serve on our board of directors include his expertise in global technology policy, cybersecurity risk management, and strategic investment.

The Board recommends a vote "FOR" the election of each of the above-named Class III Nominees


2026 Proxy Statement			5


			Table of Contents


Continuing Directors

The following Class II and Class I directors are not up for re-election at this Annual Meeting. Class I directors will be up for election at our annual meeting of stockholders in 2027 and Class II directors will be up for election at our Annual Meeting in 2028. The Preferred Directors are expected to be re-appointed upon closing of the Annual Meeting for a term of one (1) year or until their respective successors are elected and qualified.

Class I Directors (terms expiring at the 2027 annual meeting of stockholders)

Jeff McNeil

Background

Mr. McNeil has served as a member of our Board since 2023. Mr. McNeil served as Executive Vice President - Advisor at Enphase Energy Inc. (NASDAQ: ENPH) from April 2023 to July 2025, Chief Operations Officer from 2019 to 2023, and Vice President of Quality and Customer Support from 2018 to 2019. Prior to that, he served as Senior Vice President of Operations at Energous Corp. (NASDAQ: WATT) from 2016 to 2018 and held key positions at Cypress Semiconductor Corp. from 1994 to 2012, including Senior Vice President of Worldwide Operations and Vice President of Planning. Mr. McNeil earned a Bachelor of Science from San Jose University. He previously served on the board of directors of Upstart Power from 2021 to 2024 and has served on the boards of Heraeus, Digital Equipment Corp. (later acquired by Hewlett Packard Enterprise), Seagate Technology Holdings PLC (NASDAQ: STX), and Memorex.

Age: 64

Director since: 2023

Committees: Audit Committee, Leadership Development & Compensation Committee

Mr. McNeil’s qualifications to serve on our board of directors include four decades of experience spanning various facets of the energy and technology sectors and a proven track record of driving growth and innovation.


6			Eos Energy Enterprises


Table of Contents			Continuing Directors

Marian “Mimi” Walters

Background

Ms. Walters has served as a member of our Board since 2020. Ms. Walters currently serves as Chief Commercial Officer for Leading Edge Power Solutions, LLC. From 2015 to 2019, she served as a Member of the U.S. House of Representatives for California’s 45th District, where she worked on key legislation, business and policy initiatives related to energy, technology, environmental and healthcare. During her tenure, she served in House leadership and was a member of the Energy and Commerce Committee, including its Communications and Technology, Digital Commerce and Consumer Protection, and Oversight and Investigations subcommittees. Prior to serving in Congress, Ms. Walters was a member of the California State Senate from 2008 to 2014, where she served on the Banking and Financial Institutions Committee and as Vice Chair of the Appropriations Committee. She previously served in the California State Assembly and was Mayor and Councilmember for the City of Laguna Niguel. Prior to her career in public service, Ms. Walters was an investment professional at Drexel Burnham Lambert and Kidder, Peabody & Co. She earned a Bachelor of Arts from the University of California, Los Angeles. Ms. Walters currently serves on the board of directors of BRC Holdings, Inc. (NASDAQ: RILY), Pacific Specialty Insurance Company, Soaring, and Apollo Pact, a non-profit 501(c)(3).

Age: 63

Director since: 2020

Committees: Leadership Development & Compensation Committee (Chair), Nominating and Corporate Governance Committee

Ms. Walters’ qualifications to serve on our board of directors include her experience with the alternative energy industry, policy and government affairs and her background in investment banking.

Class II Directors (terms expiring at the 2028 annual meeting of stockholders)

Joe Mastrangelo

Background

Mr. Mastrangelo has served as a director and the Chief Executive Officer since the closing of the Company’s business combination with B. Riley Principal Merger Corp. II in 2020. He joined EES LLC as a Board advisor in March 2018 and assumed the role of Chief Executive Officer from August 2019 until the closing of the business combination. Before coming to Eos, Mr. Mastrangelo was President and Chief Executive Officer of General Electric's Gas Power Systems since September 2015. As an energy industry leader for the past two decades, Mr. Mastrangelo has extensive experience leading diverse teams to develop and deploy commercial scale projects around the world. Mr. Mastrangelo has broad operating experience across the energy value chain including serving as Chief Executive Officer of GE’s Power Conversion business, applying science and systems of power conversion to increase the efficiency of the world’s energy infrastructure. Mr. Mastrangelo spent ten years with GE Oil & Gas, in leadership roles in finance, quality, and commercial operations, culminating in being named a GE Corporate Officer in 2008. Mr. Mastrangelo began his career with GE in the company’s Financial Management Program and then joined GE’s Corporate Audit Staff. Originally from New York, Mr. Mastrangelo earned a Bachelor of Science in Finance from Clarkson University and an Associate of Science, Business Administration and Management from Westchester Community College.

Age: 57

Director since: 2020

Committees: N/A

Mr. Mastrangelo’s qualifications to serve on our board of directors include his extensive experience in operations management at executive level positions, as well as his educational background in finance and business.


2026 Proxy Statement			7


Continuing Directors			Table of Contents

Alex Dimitrief

Background

Mr. Dimitrief has served as a member of our Board since 2020. He is currently Global Chief of Ronald McDonald House, a partner at Zeughauser Group and an Advisory Partner at Earlylands Advisory. He previously served as Senior Vice President and General Counsel of Sotera Health Co. (NASDAQ: SHC) from November 2022 – March 2026, President and Chief Executive Officer of General Electric’s (GE) Global Growth Organization from 2015 to 2018 and as GE’s General Counsel from 2015 – 2018. Mr. Dimitrief joined GE in 2007 after spending 20 years as a litigator at Kirkland & Ellis LLP. He earned a Bachelor of Arts from Yale College and a Juris Doctor from Harvard Law School and has taught courses on corporate citizenship and corporate law at Harvard Law School and New York Law School. Mr. Dimitrief previously served as a director of both public and non-public companies, including The We Company, Synchrony Financial (NYSE: SYF), SmileDirectClub (NASDAQ: SD), and GE Capital Bank.

Age: 67

Director since: 2020

Committees: Audit Committee, Nominating and Corporate Governance Committee (Chair)

Mr. Dimitrief’s qualifications to serve on our board of directors include his extensive executive and board experiences and, his expertise in managing risk, legal compliance, governance, government affairs, and other functions at mature companies with large workforces.

Joseph Nigro

Background

Mr. Nigro has served as a member of our Board since March 25, 2025 and our Board Chair since January 1, 2026. From October 2022 to March 2023, Mr. Nigro served as an advisor to Exelon Corp.’s (Exelon) (NASDAQ: EXC) Chief Executive Officer, following his tenure as Exelon’s Chief Financial Officer from May 2018 to October 2022. Prior to that, Mr. Nigro served as Chief Executive Officer of Constellation Energy Corp. (Constellation), an Exelon operating division, from 2013 to 2018, and previously as Senior Vice President, Portfolio Strategy. Before joining Constellation, he served as Senior Vice President, Portfolio Management and Strategy, for the Exelon Power Team. Earlier in his career, Mr. Nigro held a range of leadership and commercial roles, including Vice President, Structuring and Portfolio Management; Director, Commercial Transactions; Manager, Northeast Region; Integration Lead – Power Team/Sithe New England Holdings; manager, financial trading – hedge book; and financial transaction. He also spent seven years at Phibro Energy, Inc., an independent oil trading and refining company. Mr. Nigro earned a Bachelor of Arts from the University of Connecticut and completed executive education programs at Northwestern University’s Kellogg School of Management, the University of Chicago, and the MIT Reactor Technology Course for Utility Executives. He currently serves on the board of directors of Talen Energy Corp. (NASDAQ: TLN), where he chairs the Risk Management Committee and is a member of the Governance Committee. He is a senior advisor to Blackstone Inc.’s (NYSE: BX) energy transition group and has served on the board of directors of Kindle Energy LLC (a Blackstone company) since July 2023. Mr. Nigro previously served on Exelon’s Executive Committee, chaired its Corporate Investment Committee, and served on the boards of the National Aquarium in Baltimore and the Chicago Public Library Foundation.

Age: 61

Director since: 2025

Committees: Audit Committee, Leadership Development & Compensation Committee

Mr. Nigro’s qualifications to serve on our board of directors include his extensive finance background, executive leadership experience, and deep industry knowledge, particularly in the energy sector.


8			Eos Energy Enterprises


Table of Contents			Continuing Directors

Preferred Directors Designated by the Holder of the Company’s Investor Preferred Stock

Nick Robinson

Background

Mr. Robinson has served as a member of our Board since 2024. Mr. Robinson joined Cerberus Capital Management in 2011, and his team invests in businesses driving next-generation technologies and capabilities that advance supply chain integrity. In his role, he leads investments across several industries and technologies. Mr. Robinson previously served as the Co-Chief Investment Officer of Cerberus Telecom Acquisition Corporation until the completion of its business combination with KORE Wireless in 2021. Prior to that, he served as Cerberus’ Head Trader. Mr. Robinson has led public and private deals within the areas of next generation communications, critical minerals, and grid security. He currently sits on the board of Torngat Metals, a private rare earths development company. Prior to joining Cerberus, Mr. Robinson was an Executive Director and credit trader on the high-yield and distressed desk at Morgan Stanley. He started his career in 2004 as a Credit Analyst in Goldman Sachs’ Leveraged Loan Group. Mr. Robinson graduated from Acadia University in Nova Scotia, Canada.

Age: 46

Director since: 2024

Committees: Leadership Development & Compensation Committee

Mr. Robinson’s qualifications to serve on our board of directors include his experience in investment banking and investing in emerging technology.

Gregory Nixon

Background

Mr. Nixon has served as a member of our Board since 2024. Mr. Nixon is the Chief Administrative Officer and Chief Legal Officer of M1 Support Services, LP, a Defense Aviation Company. Previously, he served in a number of senior roles at Cerberus Capital Management, including Head of Strategic Investments, Senior Managing Director, Senior Legal Counsel, and Managing Director of Cerberus Operations and Advisory Company. Prior to rejoining Cerberus in 2021, Mr. Nixon held leadership positions at DynCorp International (a Cerberus portfolio company), CH2M HILL, Inc., McKinsey & Company, and Booz Allen Hamilton Inc. (NYSE: BAH). He also served as an executive advisor to Tracker Capital Management, a venture capital firm. Prior to his career in the private sector, Mr. Nixon served in senior positions in the U.S. Department of Defense and the U.S. Government Accountability Office. His technology experience includes being a licensed patent attorney, serving as Special Intellectual Property counsel for the Defense Department, and being a commercial litigator at the international law firm of Howrey and Simon. Mr. Nixon is a retired Air Force Judge Advocate General (JAG) Officer (Lt. Colonel) and most recently served as an adjunct professor of law at Howard University Law School. He earned a Bachelor of Science from Tuskegee University and a Juris Doctor from Georgetown University Law Center. Mr. Nixon currently serves on the boards of Business Executives in National Security, Stratolaunch LLC, and Red River Technology LLC and previously served on the boards of the Thurgood Marshall Scholarship Fund and the National Inventors Hall of Fame. He is also a member of the Economic Club of Washington and the Executive Leadership Council.

Age: 62

Director since: 2024

Committees: Nominating and Corporate Governance Committee

Mr. Nixon’s qualifications to serve on our board of directors include his extensive experience in executive level leadership and strategic investing.


2026 Proxy Statement			9


Continuing Directors			Table of Contents

David Urban

Background

Mr. Urban has served as a member of our Board since 2024. Mr. Urban currently serves as Managing Director at BGR Group, a bipartisan lobbying and public relations firm, and as Of Counsel at Torridon Law PLLC. He is also a Senior Political Commentator on CNN. From 2020 to 2022, Mr. Urban served as Executive Vice President of North American Corporate Affairs for ByteDance Ltd., the parent company of TikTok. Prior to that, Mr. Urban served as President of the American Continental Group, a leading bi-partisan government affairs and strategic consulting firm. He also served as an artillery officer in the U.S. Army’s 101st Airborne Division. Mr. Urban earned a Bachelor of Science from the United States Military Academy at West Point, a Master of Government Administration from the University of Pennsylvania, and a Juris Doctor from the Temple University School of Law. He currently serves on the board directors of Virtu Financial Inc. (NYSE: VIRT), SAIC (NASDAQ: SAIC), SubCom Inc., the Johnny Mac Soldiers Fund, Edward M. Kennedy Institute for the US Senate, and the International Republican Institute as well as on the advisory boards for Coinbase Global, Inc., Voyager Space, and REGENT Craft Inc.

Age: 62

Director since: 2024

Committees: Audit Committee

Mr. Urban’s qualifications to serve on our board of directors include his experience with energy, governmental relations and policy, and background in strategic consulting.


10			Eos Energy Enterprises


Table of Contents


Corporate Governance

Board Composition

In connection with the closing of the Company’s business combination with B. Riley Principal Merger Corp. II, LLC (the “Sponsor”) in 2020, we entered into a Director Nomination Agreement (the “Director Nomination Agreement”) with the Sponsor and certain Company equity holders (the “Sellers”), pursuant to which the Sponsor and the Sellers had the right to designate members to be appointed or nominated for election to the Board of the Company, subject to terms and conditions set forth therein, in our classified board structure. Mr. Mastrangelo, Marian “Mimi” Walters and Mr. Dimitrief, were originally appointed pursuant to the Director Nomination Agreement.

Our certificate of incorporation provides the number of directors, which is fixed from time to time by a resolution of our Board. The Board currently consists of seven directors elected by the holders of common stock, and three Preferred Directors appointed by the holders of the Investor Preferred Stock (as defined below).

3 Board Classes

Class I

Class II

Class III

The directors elected by our common stockholders are divided into three classes with only one class of directors being elected in each year and each class serving a three-year term, as follows:

The terms of our Class I directors, consisting of Marian “Mimi” Walters and Jeffrey McNeil, will expire at the Company’s annual meeting of stockholders in 2027.

The terms of our Class II directors, consisting of Joe Mastrangelo, Alex Dimitrief, and Joseph Nigro, will expire at the Company’s annual meeting of stockholders in 2028.

The terms of our Class III directors, consisting of Claude Demby, Jeff Bornstein, and Nathaniel Fick, are nominated for re-election at this Annual Meeting.

The directors hold their office for a term of three years or until their respective successors are elected and qualified, subject to such director’s earlier death, resignation, disqualification or removal. In accordance with the Second Amended and Restated Bylaws of the Company, the Board will also be responsible for filling vacancies or newly created directorships on the Board that may occur between annual meetings of stockholders.

As set forth in the certificates of designation governing the Preferred Stock, at all times when holders of Preferred Stock of the Company (the “Investor Preferred Stock”), beneficially own at least 10.0%, 15.0% or 30.0% of the capital stock of the Company, such holders of Investor Preferred Stock, exclusively and voting together as a separate class, have the right to appoint one (1), two (2) or three (3) Preferred Directors, respectively, to the Board. At all times holders of the Investor Preferred Stock beneficially own at least 40.0% of the capital stock of the Company, such holders of the Investor Preferred Stock, exclusively and voting together as a separate class, will have the right to nominate and designate a fourth director, who shall be designated by the Board or the nominating committee of the Board to a class of directors elected by the holders of the Company’s common stock and thereafter


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stand for election as a director on the Board elected by the holders of the Company’s common stock; provided that, the nominating committee of the Board determines that such appointment of the fourth director not result in a change of control under any Company governing documents or violate any applicable laws, including requirements of the SEC and Nasdaq Global Select Market (“Nasdaq”). Any such fourth director’s appointment shall be subject to and conditioned upon compliance by the holders of the Investor Preferred Stock with the Hart-Scott-Rodino Antitrust Improvements Act of 1976, including the submission of any required filings and the expiration or termination of any applicable waiting periods, which have expired. In the event that any such fourth director is not approved by the holders of common stock of the Company at the applicable annual meeting of stockholders, the holders of record of the shares of Investor Preferred Stock will have the right to appoint and elect a replacement for such director, pursuant to the approval requirements set forth above. To the extent any of such directors qualify to serve on any committees of the Board, for each such committee for which at least one (1) director is qualified, at least one (1) such director will be invited to serve on such committee of the Board. So long as the holders of Investor Preferred Stock have a right to appoint a director, the holders thereof will have the right to appoint a non-voting observer to the Board. At all times when the holders of Investor Preferred Stock have a right to appoint a director, the holders of Investor Preferred Stock shall not vote any shares of common stock they receive upon the conversion of any Investor Preferred Stock or the exercise of any warrants in any election of directors. The holders of Investor Preferred Stock have appointed Gregory Nixon, Nick Robinson, and David Urban as Preferred Directors. As of the date of this proxy statement, the holders of Investor Preferred Stock have not exercised their right to nominate a fourth director to serve as a common director and do not currently have the right. The holders of Investor Preferred Stock may appoint new Preferred Directors at any time.

Continuously Improving Our Board and Director Nomination and Recommendation Considerations

As the Company evolves, so will our Board. The Company and its Board are committed to continuing to develop a Board comprising experienced and qualified directors with integrity and expertise who can serve as effective stewards for an increasingly diverse base of stockholders and other stakeholders and institute robust governance principles.

To this end, our Board has instituted a process designed to regularly review the mix of skills and experience of our current directors and those it expects would be desirable in the future, including industry experience; public company experience; operational, manufacturing and supply chain expertise, especially in high-technology start-ups; finance and accounting, including capital markets expertise; cognitive diversity, including personal and professional experience; enterprise risk management; regulation and government affairs; talent development; environmental, social and governance (“ESG”) and sustainability; and growth, with a focus on leading businesses through periods of significant growth and transformation and exposure to various domestic and international markets. The Board also assesses its own performance and the performance of its committees.

We view continuous self-improvement of our corporate governance processes as an imperative for the Nominating and Corporate Governance Committee and our Board. We have retained Heidrick & Struggles to provide consulting and assistance in support of the Company’s Board composition and effectiveness planning. We selected Heidrick & Struggles based on its record as a preeminent firm in working with boards on succession planning, board effectiveness and culture shaping.

Directors are expected to possess certain personal traits and, in fulfilling its responsibility to identify qualified candidates for membership on the Board, the Nominating and Corporate Governance Committee will examine each director nominee on a case-by-case basis and take into account all factors it considers appropriate, including those described above as well as, enhanced independence, financial literacy and financial expertise, diversity of background and perspective, and any other relevant qualifications, attributes or skills.

The Nominating and Corporate Governance Committee evaluates stockholder recommendations using the same process it follows for other candidates. Recommendations do not constitute candidate nominations, which must meet the requirements in our Second Amended and Restated Bylaws. Should stockholders wish to recommend a director candidate, such correspondence should be sent to the attention of our Secretary at 3920 Park Avenue, Edison, NJ 08820. The Nominating and Corporate Governance Committee may request such additional information as it deems appropriate.


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Independence of the Board of Directors

Nasdaq rules require that a majority of our Board be independent. Consistent with its charter, the Nominating and Corporate Governance Committee has reviewed the relationships between directors, the Company and members of management and recommended to the Board whether each director qualifies as “independent” under the Board’s definition of “independence” and the applicable rules of Nasdaq and the Company’s Corporate Governance Guidelines. Our Board has determined that ten of the eleven directors, Jeff Bornstein, Claude Demby, Alex Dimitrief, Nathaniel Fick, Jeffrey McNeil, Joseph Nigro, Greg Nixon, Nick Robinson, Marian “Mimi” Walters, and David Urban are “independent directors” as defined in the rules of Nasdaq and applicable SEC rules.

Board Leadership Structure

Mr. Nigro serves as the Chair of the Board and is an independent member of the Board. The Independent Directors meet in executive session without non-Independent Directors or management present no less than twice per year. Each executive session of the Independent Directors is presided over by the Chair of the Board.

Our Board believes that, at this time, the foregoing structure separating the Chair of the Board and CEO roles achieves an appropriate balance between the effective development of key strategic and operational objectives by the CEO, and independent oversight of management’s execution of such objectives. Our Board also believes that this structure improves its risk oversight function. Our Board also periodically evaluates our leadership structure to determine if it remains in our best interests based on circumstances existing at the time. If the Chair of the Board is a member of management or does not otherwise qualify as independent, the Independent Directors may elect a Lead Director.

Committees of the Board of Directors

Our Board has three fully independent standing committees: the Audit Committee, the Leadership Development & Compensation Committee and the Nominating and Corporate Governance Committee. Each of the committees reports to the Board as they deem appropriate and as the Board may request.

The Board recently established, effective after the Annual Meeting, a Safety and Operations Oversight Committee to drive operational excellence and enhance the Company’s manufacturing capabilities through rigorous monitoring of its production systems and risk profile. This dedicated oversight structure is designed to bolster manufacturing performance and safety standards while ensuring that Company management remains empowered to execute the day-to-day tactical operations .

The following table presents the standing committees of the Board, the current membership of the committees and the number of times each committee met in 2025.


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Director Name	Audit	Leadership Development & Compensation	Nominating and Corporate Governance

Jeff Bornstein	l	l
Claude Demby	l		l
Alex Dimitrief	l		l
Nathaniel Fick(1)			l
Jeff McNeil	l	l
Marian “Mimi” Walters		l	l
Joseph Nigro	l	l
Gregory Nixon			l
Nick Robinson		l
David Urban	l
Number of Meetings Held in 2025	10	4	5

1.Mr. Fick was added to the Board in 2026 and did not attend any meetings in 2025.


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Audit Committee

The Company’s Audit Committee oversees the Company’s corporate accounting and financial reporting process and the Company’s compliance with legal and regulatory requirements.

Among other matters, the Audit Committee:

•appoints our independent registered public accounting firm;

•evaluates the independent registered public accounting firm’s qualifications, independence and performance;

•determines the engagement of the independent registered public accounting firm;

•reviews and approves the scope of the annual audit and the audit fee;

•discusses with management and the independent registered public accounting firm the results of the annual audit and the review of the Company’s quarterly financial statements;

•approves the retention of the independent registered public accounting firm to perform any proposed permissible non-audit services;

•monitors the rotation of the lead audit partner of the independent registered public accounting firm on the Company’s engagement team in accordance with requirements established by the SEC;

•is responsible for reviewing our financial statements and our management’s discussion and analysis of financial condition and results of operations to be included in our annual and quarterly reports to be filed with the SEC;

•is responsible for cybersecurity and data privacy risks, controls and procedures;

•reviews our critical accounting policies and practices; and

•reviews the audit committee charter and the committee’s performance at least annually.

The current members of the Audit Committee are Jeff Bornstein, Claude Demby, Alex Dimitrief, Jeffrey McNeil, Joseph Nigro, and David Urban, with Jeff Bornstein serving as the chair of the committee. Under the rules of the SEC, members of the Audit Committee must also meet heightened independence standards. All of the members of the Audit Committee are independent directors as defined under the applicable rules and regulations of the SEC and Nasdaq with respect to Audit Committee membership. Jeff Bornstein qualifies as an “audit committee financial expert,” as such term is defined in Item 407(d)(5)(ii) of Regulation S-K.

Number of Meetings Held in 2025: 10

Committee Members:

•Jeff Bornstein (Chair)

•Claude Demby

•Alex Dimitrief

•Jeff McNeil

•Joseph Nigro

•David Urban


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Leadership Development & Compensation Committee

Our Leadership Development & Compensation Committee (the "Compensation Committee") reviews and recommends policies relating to compensation and benefits of our officers and employees.

Among other matters, the Compensation Committee:

•establishes, reviews, and approves corporate goals and objectives of the Company’s management compensation programs, its basic compensation policies and annual and long-term performance goals and objectives;

•reviews the Company’s employee compensation policies and practices;

•reviews and approves any employment, compensation, benefit or severance agreement with any executive officer;

•evaluates the performance of executive officers against corporate goals and objectives and recommends to our Board the compensation of these officers based on such evaluations;

•reviews, approves and recommends to the Board the adoption of any equity-based compensation plan for employees of or consultants to the Company and any modification of any such plan; and

•reviews and evaluates, at least annually, the directors' compensation and makes recommendations thereon to the Board.

Pursuant to the Compensation Committee’s charter, the Compensation Committee may, by resolution approved by a majority of the Compensation Committee members, form and delegate any of its responsibilities to a subcommittee so long as such subcommittee is solely comprised of one or more members of the Committee and such delegation is not otherwise inconsistent with law and applicable rules and regulations of the SEC and Nasdaq. The Compensation Committee may also, in certain instances by resolution approved by a majority of the Compensation Committee members, delegate to management the administration of the Company’s incentive compensation and equity-based compensation plans, to the extent permitted by law and as may be permitted by such plans and subject to such rules, policies and guidelines (including limits on the aggregate awards that may be made pursuant to such delegation) as the Compensation Committee shall approve.

The Compensation Committee consults with members of our management team, including our CEO, when making compensation decisions. While the Compensation Committee considers our CEO’s recommendations, the Compensation Committee ultimately uses its own business judgment and experience in approving, or making recommendations to the Board, where applicable, regarding individual compensation elements and the amount of each element for our NEOs. Our CEO recuses himself from all determinations regarding his own compensation. The current members of our Company’s Compensation Committee are Jeff Bornstein, Jeffrey McNeil, Joseph Nigro, Nick Robinson and Marian “Mimi” Walters, with Marian "Mimi" Walters serving as the chair of the committee.

Our Board has determined that each member of the Compensation Committee meets the independence requirements under the applicable rules and regulations of the SEC and the applicable listing standards of Nasdaq, and each, with the exception of Nick Robinson, is a “non-employee director” as defined in Rule 16b-3 promulgated under the Securities Exchange Act of 1934. As Mr. Robinson does not qualify as a "non-employee director" as defined in Rule 16b-4 promulgated under the Securities Exchange Act of 1934, Mr. Robinson recuses himself from all determinations involving equity awards to executive officers and directors.

Number of Meetings Held in 2025: 4

Committee Members:

•Marian “Mimi” Walters (Chair)

•Jeff Bornstein

•Jeffrey McNeil

•Joseph Nigro

•Nick Robinson

SEC Form PRE 14A filed by Eos Energy Enterprises Inc.