Director at Constellium (CSTM) sells 10,000 shares in open market

Rhea-AI Filing Summary

Constellium SE director Isabelle Boccon-Gibod reported an open-market sale of 10,000 ordinary shares. The sale took place on February 26, 2026 at a weighted average price of $25.77 per share, executed through multiple transactions at that price. After this sale, she directly owns 23,000 ordinary shares of Constellium SE.

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^*

Boccon-Gibod Isabelle

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
02/26/2026

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	02/26/2026		S		10,000	D	$25.77(1)	23,000	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. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.77, to $25.77, inclusive. The reporting person undertakes to provide to Constellium SE, any security holder of Constellium SE, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein.

Remarks:

	/s/ Kristine Carpenter, Attorney-in-Fact for Isabelle Boccon-Gibod	02/27/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did Constellium (CSTM) disclose in this Form 4?

Constellium disclosed that director Isabelle Boccon-Gibod sold 10,000 ordinary shares in an open-market transaction. The sale was reported on a Form 4 and reflects a routine insider share sale rather than an acquisition of additional stock.

At what price did the Constellium (CSTM) director sell shares?

The director’s reported sale used a weighted average price of $25.77 per share. According to the filing, the shares were sold in multiple transactions, all at prices within a narrow range, effectively matching the disclosed weighted average sale price.

How many Constellium (CSTM) shares does the director hold after the sale?

Following the reported transaction, director Isabelle Boccon-Gibod now directly owns 23,000 ordinary shares of Constellium SE. This post-transaction balance is disclosed in the Form 4 as the total number of shares held after completing the open-market sale.

Was the Constellium (CSTM) insider transaction a buy or a sell?

The Form 4 shows a sale of Constellium SE ordinary shares by director Isabelle Boccon-Gibod. The transaction code is “S”, which indicates a sale in the open market or a private transaction, and is classified as a non-derivative share disposal.

How many Constellium (CSTM) shares were sold in this insider trade?

The insider transaction involved the sale of 10,000 ordinary shares of Constellium SE. These were non-derivative securities sold in an open-market transaction, with the total quantity clearly disclosed in the Form 4 transaction detail section for this filing.