Constellium : Proxy Statement AGM 2025

Constellium SE

Washington Plaza

40-44 rue Washington

75008 Paris, France

PROXY STATEMENT

FOR THE ANNUAL GENERAL MEETING OF SHAREHOLDERS

to be held on May 15, 2025

The Proxy Statement and Annual Report are available at

http://www.constellium.com

This Proxy Statement is being furnished to you by the Board of Directors of Constellium SE (the ''Company,'' ''Constellium SE'' ''our,'' ''us,'' or ''we'') to solicit your proxy to vote your ordinary shares, nominal value €0.02 per share at our 2025 Annual General Meeting of Shareholders. The Annual General Meeting will be held on May 15, 2025, at 5:00 pm CET (11:00 am EDT), at the registered office of the Company at Washington Plaza, 40-44 Rue Washington, 75008 Paris, France.

We intend that this Proxy Statement and the accompanying proxy card will be first made available on or about April 15, 2025 to holders of our ordinary shares registered on the U.S Register as of April 9, 2025.

Letter from the Chairman and CEO of Constellium

Dear Constellium Shareholders:

On behalf of Constellium SE, we are pleased to invite you to review our 2025 Proxy Statement. This document outlines key matters to be presented at our upcoming Annual General Meeting on May 15, 2025, at 5:00 pm CET (11:00 am EDT), and we encourage your participation and engagement as valued shareholders in our company.

As we decided to voluntarily file our SEC reports on U.S. domestic issuer forms in 2025, including our Annual Report for the fiscal year 2024 (Form 10-K) earlier this year, we also elected to voluntarily file this Proxy Statement with the SEC on a U.S. domestic issuer form (utilizing Form 8-K) for our upcoming Annual General Meeting. We believe that this new format, which includes additional information on governance and executive compensation, will provide useful insights to our shareholders.

In this Proxy Statement, you will find important details regarding the items to be voted on, including the election of directors. We believe these proposals align with our mission to drive sustainable profitability and uphold the highest standards of corporate responsibility.

Constellium is deeply committed to sound corporate governance and executive compensation policies and practices to ensure we operate responsibly, efficiently, and in the best interests of shareholders. The diversity of experience, background and skills present in the boardroom allows for active Board oversight of the opportunities and issues ahead of Constellium as we make progress on our strategic roadmap. Our Board strikes the right balance between fresh perspectives and established experience, as we regularly add new directors to the Board. This year, we are pleased to submit to vote the nomination of Mr. Bradley L. Soultz to our Board. As the current CEO of WillScot and a former executive at Novelis, he brings an impressive combination of skills, experience, and deep industry knowledge with his background in aluminum fabrication that will serve our shareholders, Constellium and our Board well.

Looking at our recent performance, 2024 was a challenging year for us on many fronts. The year began with the extreme cold weather and snow impacting operations at Muscle Shoals in January and we experienced severe flooding at our facilities in the Valais region in Switzerland during the summer. In addition, we faced market-driven headwinds starting mid last-year and which became more pronounced in the second half, including demand weakness across most of our end markets and significant tightening of scrap spreads in North America. Despite all of these challenges in the near-term, we have demonstrated that we have the right strategy, the right teams, and the right products in the right markets, and that we know how to overcome crises. Our business model is flexible and resilient; our diversified portfolio allows us to always have options in very different market conditions; we have built the balance sheet we need to both weather crises and seize opportunities; and our high-value, recyclable and sustainable products respond to the growing needs of our customers. As such, back in February this year we provided financial guidance for 2025 and established new long-term financial targets for 2028. At Constellium, we remain committed to delivering long-term value to our shareholders through innovation, operational excellence, and a focus on commercial and capital discipline. We believe we are well-positioned for long-term success and remain focused on executing our strategy and shareholder value creation.

To wrap up, thank you for your continued trust and investment in Constellium. Your vote is critical in shaping the future of Constellium, and we encourage you to participate in this process. Whether you choose to vote online, by mail, or in person at the Annual General Meeting, your voice matters. We look forward to your engagement and a productive discussion at the upcoming meeting.

Sincerely,
/s/ Jean-Christophe Deslarzes	/s/ Jean-Marc Germain
Jean-Christophe Deslarzes	Jean-Marc Germain
Chairman of the Board	CEO

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EXPLANATORY NOTE

Constellium SE (''Constellium SE'' or the '' Company''), a company organized under the laws of France, qualifies as a foreign private issuer, as determined by Rule 3b-4 under the Securities Exchange Act of 1934 (the ''Exchange Act'') and is exempt from the proxy solicitation rules under Section 14 of the Exchange Act (including the requirement to furnish a Proxy Statement in accordance with Schedule 14A thereof) and Regulation FD. However, beginning in 2025, Constellium SE has decided to voluntarily file its quarterly and annual reports with the U.S. Securities and Exchange Commission (the ''SEC'') on U.S. domestic company forms. Constellium US Holdings I, LLC which is a subsidiary of Constellium SE also maintains the following IRS Identification Number: 27-4126819.

Following its decision to voluntarily file reports on U.S. domestic company forms, starting with its annual report on Form 10-K (the ''Annual Report'') for the fiscal year 2024 filed earlier this year, the Company has also elected to voluntarily publish a proxy statement for its annual general meeting to be held in 2025 (''Annual General Meeting'' or the ''Shareholders Meeting'') in a format intended to substantially comply with the requirements of Schedule 14A of the Exchange Act. Therefore, our fiscal year 2024 disclosures with respect to the notice of and solicitation of votes for our Annual General Meeting are now in a different format than previous years.

Shareholders this year are receiving this Notice of 2025 Annual General Meeting and the proxy statement (the ''Proxy Statement'') and the Annual Report.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

Certain statements contained in this report may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. This report may contain ''forward-looking statements'' with respect to our business, results of operations and financial condition, and our expectations or beliefs concerning future events and conditions. You can identify forward-looking statements because they contain words such as, but not limited to, ''believes,'' ''expects,'' ''may,'' ''should,'' ''approximately,'' ''anticipates,'' ''estimates,'' ''intends,'' ''plans,'' ''targets,'' likely,'' ''will,'' ''would,'' ''could'' and similar expressions (or the negative of these terminologies or expressions). All forward-looking statements involve risks and uncertainties. Many risks and uncertainties are inherent in our industry and markets, while others are more specific to our business and operations. These risks and uncertainties include, but are not limited to: market competition; economic downturn or industry specific conditions including the impacts of tax and tariff programs, inflation, foreign currency exchange, and industry consolidation; disruption to business operations; natural disasters including severe flooding and other weather-related events; the conflict between Russia and Ukraine and other geopolitical tensions; the inability to meet customer demand and quality requirements; the loss of key customers, suppliers or other business relationships; supply disruptions; excessive inflation; the capacity and effectiveness of our hedging policy activities; the loss of key employees; levels of indebtedness which could limit our operating flexibility and opportunities; and other risk factors set forth under the heading ''Risk Factors'' in our Annual Report on Form 10-K, and as described from time to time in subsequent reports filed with the U.S. Securities and Exchange Commission. The occurrence of the events described, and the achievement of the expected results depend on many events, some or all of which are not predictable or within our control. Consequently, actual results may differ materially from the forward-looking statements contained in this Proxy Statement. We undertake no obligation to update or revise any forward-looking statement as a result of new information, future events or otherwise, except as required by law.

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NOTICE OF 2025 ANNUAL GENERAL MEETING

The Annual General Meeting of Constellium SE (the '' Company'') will be held on Thursday, May 15, 2025, starting at 5:00 pm CET (11:00 am EDT) at the registered office of the Company at Washington Plaza, 40-44 rue Washington, 75008 Paris, France.

Shareholders whose shareholding is registered on the U.S. Register with Computershare Trust Company, N.A., in accordance with article 7 of the Company's articles of association, are entitled to exercise their voting rights as instructed below.

Shareholders whose shareholding is registered on the French Register, in accordance with article 7 of the Company's articles of association, are entitled to exercise their voting rights as instructed in the notice (avis de réunion) published in the French official journal (the Bulletin des Annonces Légales Obligatoires (BALO)) dated April 9, 2025.

A. AGENDA FOR THE ANNUAL GENERAL MEETING

The agenda for the Annual General Meeting (the ''Agenda'') is comprised of the following proposed Ordinary Resolutions and Extraordinary Resolutions:

ORDINARY RESOLUTIONS / PROPOSALS

1. Appointment of Mr. Bradley Soultz as a director for a term of three years
2. Re-appointmentof Mr. Emmanuel Blot as a director for a term of three years
3. Re-appointmentof Ms. Martha Brooks as a director for a term of three years
4. Re-appointmentof Ms. Lori Walker as a director for a term of three years
5. Approval of the statutory financial statements and transactions for the fiscal year ended December 31, 2024
6. Approval of the consolidated financial statements and transactions for the fiscal year ended December 31, 2024
7. Discharge (quitus) of the directors, the Chief Executive Officer, and the Statutory Auditors of the Company in respect of the performance of their duties for the fiscal year ended December 31, 2024
8. Allocation of the results of the Company for the fiscal year ended December 31, 2024
9. Re-appointmentof PricewaterhouseCoopers Audit and appointment of RSM France as the Statutory Auditors
10. Appointment of PricewaterhouseCoopers Audit as a Statutory Auditor in charge of certifying the consolidated sustainability information
11. Authorization to be given to the Board of Directors for the repurchase by the Company of its own shares in accordance with article L. 225-209-2 of the French Commercial Code

EXTRAORDINARY RESOLUTIONS/PROPOSALS

1. Authorization to be given to the Board of Directors to reduce the Company's share capital by cancelling shares acquired pursuant to the authorization for the Company to repurchase its own shares in accordance with the provisions of article L. 225-209-2 of the French Commercial Code
2. Authorization to be given to the Board of Directors to reduce the Company's share capital by cancelling the shares acquired by the Company pursuant to the provisions of article L. 225-208 of the French Commercial Code
3. Delegation of competence to the Board of Directors to increase the Company's share capital by issuance of ordinary shares or other securities, with preferential subscription rights, up to 1,468,198.84 euros (representing 50% of the share capital), for a 26 month-period
4. Delegation of competence to the Board of Directors to increase the Company's share capital by issuance of ordinary shares or other securities, without preferential subscription rights, by way of a public offering other than within the meaning of article L. 411-2 1° of the French Monetary and Financial Code, up to 880,919 euros (representing 30% of the share capital), for a 26 month-period

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1. Delegation of competence to the Board of Directors to increase the Company's share capital by issuance of ordinary shares or other securities, without preferential subscription rights, by way of an offering within the meaning of article L. 411-2 1° of the French Monetary and Financial Code, up to 587,279.54 euros (representing 20% of the share capital), for a 26 month-period
2. Delegation of competence to the Board of Directors to increase the number of shares issued in case of a capital increase, without preferential subscription rights, by way of a public offering other than within the meaning of article L. 411-2 1° of the French Monetary and Financial Code, in accordance with article L. 225-135-1 of the French Commercial Code, by up to 15%, for a 26 month-period
3. Delegation of competence to the Board of Directors to increase the number of shares issued in case of a capital increase, without preferential subscription rights, by way of an offering within the meaning of article L. 411-2 1° of the French Monetary and Financial Code, in accordance with article L. 225-135-1 of the French Commercial Code, by up to 15%, for a 26 month-period
4. Delegation of competence to the Board of Directors to increase the Company's share capital by issuance of new shares of the Company to participants to an employee savings plan without preferential subscription rights, up to 29,363.98 euros (representing 1% of the share capital), for a 26 month-period
5. Amendment of article 13 of the articles of association
6. Amendment of article 20 of the articles of association
7. Powers to carry out formalities

B. ANNUAL GENERAL MEETING DOCUMENTS

Details of the Annual General Meeting have been published in the French official journal (the Bulletin des Annonces Légales Obligatoires (BALO)) on April 9, 2025. In addition, the Company will post on the Company's website at www.constellium.com and make available to the shareholders entitled to vote at the Annual General Meeting, free of charge at the offices of the Company by contacting the Corporate Secretary at [e-mail]:

1. its Annual Report for fiscal year 2024 filed with the SEC on February 28, 2025, which includes consolidated financial statements of the Company for the fiscal year ended December 31, 2024, prepared in accordance with generally accepted accounting principles as applied in the United States (''U.S. GAAP'');
2. the documents prepared for the purposes of the Annual General Meeting including notably:
3. • the Proxy Statement and the proxy card (for shareholders on the U.S. Register);
   • the statutory financial statements of the Company for the fiscal year ended December 31, 2024, prepared in accordance with French accounting principles (''French GAAP'');
   • the consolidated financial statements of the Company for the fiscal year ended December 31, 2024, prepared in accordance with International Financial Reporting Standards (''IFRS'');
   • the Report of the Board of Directors (which includes the proposed resolutions and explanatory statements);
   • the Management Report for 2024; and
   • the reports of the Statutory Auditors.

C. U.S. RECORD DATE AND FRENCH RECORD DATE

U.S. Register: Shareholders whose shareholding is registered on the U.S. Register maintained by Computershare Trust Company, N.A. are entitled to receive meeting materials and are entitled to exercise their voting rights as instructed below.

French Register: Shareholders whose shareholding is registered on the French Register are entitled to receive meeting materials and exercise their voting rights as instructed in the notice (avis de réunion) published in the French official journal (the Bulletin des Annonces Légales Obligatoires (BALO)) dated April 9, 2025.

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For the Annual General Meeting:

1. the ''U.S. Record Date'' is April 9, 2025: a Notice of Internet Availability of Proxy Materials will be mailed promptly after the U.S Record Date to the shareholders whose shareholding is registered on the U.S. Register as of the U.S. Record Date;
2. the ''French Record Date'' (as defined applying French law rules) is May 13, 2025, 0:00 (zero hour) (Paris time):
3. • Shareholders who purchase shares between the U.S. Record Date and the French Record Date are entitled to participate to, and vote at, the Annual General Meeting as long as they continue to be shareholders on the French Record Date.
   • Only votes of shareholders whose shareholding is registered (either on the U.S. Register or on the French Register) on the French Record Date will be counted.Consequently, for any shareholders who vote and subsequently dispose of their shares before the French Record Date, the votes in respect of these shares will not be counted for final voting purposes.

D. MAILING AND DOCUMENT AVAILABILITY

Promptly after the U.S. Record Date, shareholders whose shareholding is registered on the U.S. Register with Computershare Trust Company, N.A. as of the U.S. Record Date will receive a Notice of Internet Availability of Proxy Materials including instructions on how to access the proxy materials, and if requested, physical copies of our Proxy Statement and Annual Report, free of charge, by contacting the Corporate Secretary at [e-mail].

The proxy materials will also be available on the Company's website at www.constellium.com.

E. REGISTRATION FOR THE ANNUAL GENERAL MEETING

Shareholders who wish (i) to attend the Annual General Meeting in person or (ii) to authorize others to represent them at the meeting are required to register on www.proxyvote.com by clicking on ''shareholder meeting registration'' no later than 12:00 pm (noon) EDT on May 13, 2025. Beneficial owners who wish to attend the Annual General Meeting in person must also request a ''legal proxy'' from the entity/broker who holds shares on their behalf.

F. PROXY CARD AND VOTING INSTRUCTIONS

Shareholders whose shareholding is on the U.S. Register with Computershare Trust Company, N.A. may vote as follows:

BY INTERNET - www.proxyvote.com

Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 pm EDT on May 14, 2025. Please have your proxy card in hand when you access the website and follow the instructions to obtain your records and to create an electronic voting instruction form.

BY PHONE

1-800-690-6903

Use any touch-tone telephone to transmit your voting instructions up until 11:59 pm EDT on May 14, 2025. Please have your proxy card in hand and then follow the instructions.

BY MAIL

Fill in, sign and date your proxy card and return it so it is received by 11:59 pm EDT on May 14, 2025, in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717.

You can change your vote or revoke your vote at any time prior to 11:59 p.m. EDT on May 14, 2025. You may vote again up until 11:59 p.m. EDT on May 14, 2025 using the internet, phone, or mail as disclosed above.

Your vote is important.Please read the Proxy Statement and the accompanying materials. Whether or not you plan to attend the Annual General Meeting, and no matter how many shares of the Company you own, please submit your proxy card or voting instruction form, as applicable, in accordance with the procedures described above.

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TABLE OF CONTENTS
EXPLANATORY NOTE	i
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	i
NOTICE OF 2025 ANNUAL GENERAL MEETING	ii
QUESTIONS AND ANSWERS ABOUT THE ANNUAL GENERAL MEETING	1
BOARD OF DIRECTORS AND CORPORATE GOVERNANCE	5
RESOLUTIONS PROPOSED TO THE ANNUAL GENERAL MEETING	22
RESOLUTION / PROPOSAL 1	22
RESOLUTION / PROPOSAL 2	22
RESOLUTION / PROPOSAL 3	22
RESOLUTION / PROPOSAL 4	23
RESOLUTIONS / PROPOSALS 5 AND 6	23
RESOLUTION / PROPOSAL 7	24
RESOLUTION / PROPOSAL 8	24
RESOLUTION / PROPOSAL 9	25
RESOLUTION / PROPOSAL 10	25
RESOLUTION / PROPOSAL 11	26
RESOLUTION / PROPOSAL 12	28
RESOLUTION / PROPOSAL 13	29
RESOLUTION / PROPOSAL 14	30
RESOLUTION / PROPOSAL 15	32
RESOLUTION / PROPOSAL 16	34
RESOLUTIONS / PROPOSALS 17 AND 18	36
RESOLUTION / PROPOSAL 19	38
RESOLUTION / PROPOSAL 20	39
RESOLUTION / PROPOSAL 21	41
RESOLUTION / PROPOSAL 22	42
COMPENSATION DISCUSSION AND ANALYSIS	43
HUMAN RESOURCES COMMITTEE REPORT	50
FISCAL YEAR 2024 SUMMARY COMPENSATION TABLE	51
FISCAL YEAR 2024 GRANTS OF PLAN BASED AWARDS	52
OUTSTANDING EQUITY AWARDS AT 2024 FISCAL YEAR END	54
STOCK VESTED IN FISCAL YEAR 2024	55
PENSION BENEFITS FISCAL YEAR 2025	55
NON-QUALIFIED DEFERRED COMPENSATION FOR FISCAL YEAR 2024	56
POTENTIAL PAYMENTS UPON TERMINATION OF EMPLOYMENT OR CHANGE IN
CONTROL	57
PAY RATIO	59
PAY VERSUS PERFORMANCE	60
FISCAL YEAR 2024 DIRECTOR COMPENSATION	65
COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION	66
AUDIT COMMITTEE REPORT	66
INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM	67
OWNERSHIP OF SECURITIES	68
CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS	70
PROCEDURES FOR SHAREHOLDER PROPOSALS FOR THE ANNUAL GENERAL MEETING	71
IMPORTANT NOTICE REGARDING DELIVERY OF SHAREHOLDER DOCUMENTS	71
ANNEX A - BRADLEY SOULTZ	A-1
ANNEX B - EMMANUEL BLOT	B-1
ANNEX C - MARTHA BROOKS	C-1
ANNEX D - LORI WALKER	D-1

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