Constellium (CSTM) SVP gains shares as performance awards vest, small tax sale

Rhea-AI Filing Summary

Constellium SE senior vice president and chief procurement officer Marcus Becker reported the vesting of performance-based stock awards and a small related share sale. On March 9, 2026, previously granted performance stock units vested, delivering 14,592 ordinary shares at no cash purchase price.

On March 10, 2026, Becker disposed of 1,113 ordinary shares solely to satisfy tax withholding obligations triggered by the vesting of restricted stock unit and performance stock unit awards. After these transactions, he directly held 33,237 ordinary shares, reflecting a net increase in his equity position.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Becker Marcus

(Last) (First) (Middle)

300 EAST LOMBARD STREET

SUITE 1710

(Street)

BALTIMORE MD 21202

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CONSTELLIUM SE [ CSTM ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP CPO

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary shares	03/09/2026		P		14,592(1)	A	$0	34,350	D
Ordinary shares	03/10/2026		S(2)		1,113	D	$25.87	33,237	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents earned non-derivative performance stock units of Constellium SE (the "Issuer") granted on March 9, 2023 that contained performance-vesting requirements, which vested on March 9, 2026.

2. The Reporting Person sold 1,113 ordinary shares of the Issuer upon the vesting of restricted stock unit and performance stock unit awards previously granted on March 9, 2023, solely to satisfy tax withholding obligations incurred upon vesting.

Remarks:

	/s/ Kristine Carpenter, Attorney-in-Fact for Marcus Becker	03/11/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transactions did CSTM executive Marcus Becker report?

Marcus Becker reported vesting of performance stock units and a related tax sale. 14,592 ordinary shares were delivered on March 9, 2026, and 1,113 shares were sold on March 10, 2026 solely to cover tax withholding obligations from those awards.

Did the CSTM insider sale reflect a change in Marcus Becker’s outlook?

The filing states the 1,113-share sale was solely to satisfy tax withholding obligations. This indicates a mechanical disposition tied to award vesting rather than a discretionary decision to reduce exposure or signal a changed view on Constellium SE’s prospects.

How many Constellium (CSTM) shares does Marcus Becker hold after these transactions?

Following the March 10, 2026 tax-related sale, Marcus Becker directly holds 33,237 ordinary shares of Constellium SE. This reflects the net impact of the March 9, 2026 vesting of performance stock units and the small share sale to cover tax obligations.

What type of equity awards vested for the CSTM executive on March 9, 2026?

The filing describes earned non-derivative performance stock units granted on March 9, 2023 that contained performance-vesting requirements. These units vested on March 9, 2026, resulting in delivery of ordinary shares of Constellium SE to Marcus Becker without a cash purchase price.

Was Marcus Becker’s 1,113-share CSTM sale an open-market trade?

Although coded as a sale, the footnote clarifies 1,113 ordinary shares were sold upon vesting of restricted and performance stock unit awards solely to satisfy tax withholding obligations. This characterizes the sale as tax-driven rather than a discretionary open-market trade.