Constellium (CSTM) SVP Brun sells 17,701 shares and gains performance stock

Rhea-AI Filing Summary

Constellium SE senior vice president Nicolas Brun reported two transactions in the company’s ordinary shares. On March 9, 2026, he completed an open-market sale of 17,701 shares at a weighted-average price of $24.67 per share, with individual trades ranging from $24.63 to $24.72. The same day, he acquired 23,710 shares at no cost, representing earned performance stock units originally granted on March 9, 2023 that vested on March 9, 2026. Following these transactions, Brun directly holds 127,176 ordinary shares of Constellium SE.

Insider Trade Summary

Net Seller: 17,701 shares ($436,684)

Net Sell 2 txns

Insider Brun Nicolas

Role SVP PA, Comm & Sust

Sold 17,701 shs ($437K)

Type	Security	Shares	Price	Value
Sale	Ordinary shares	17,701	$24.67	$437K
Grant/Award	Ordinary shares	23,710	$0.00	--

Holdings After Transaction: Ordinary shares — 103,466 shares (Direct)

Footnotes (1)

1. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.63 to $24.72, 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. Represents earned non-derivative performance stock units of the Issuer granted on March 9, 2023 that contained performance-vesting requirements, which vested on March 9, 2026.

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Brun Nicolas

(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 PA, Comm & Sust

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		S		17,701(1)	D	$24.67	103,466	D
Ordinary shares	03/09/2026		A		23,710(2)	A	$0	127,176	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 $24.63 to $24.72, 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.

2. Represents earned non-derivative performance stock units of the Issuer granted on March 9, 2023 that contained performance-vesting requirements, which vested on March 9, 2026.

Remarks:

	/s/ Kristine Carpenter, Attorney-in-Fact for Nicolas Brun	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).
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 transactions did CSTM executive Nicolas Brun report on March 9, 2026?

Nicolas Brun reported two transactions on March 9, 2026: an open-market sale of 17,701 Constellium SE ordinary shares and a grant of 23,710 shares. The grant reflects vested performance stock units originally awarded in March 2023.

How many CONSTELLIUM SE (CSTM) shares did Nicolas Brun sell and at what price?

He sold 17,701 ordinary shares in an open-market transaction at a weighted-average price of $24.67 per share. Individual sale prices ranged from $24.63 to $24.72, according to the disclosed weighted-average pricing footnote.

What is the nature of the 23,710 CSTM shares acquired by Nicolas Brun?

The 23,710 acquired shares represent earned performance stock units that vested into ordinary shares. These units were granted on March 9, 2023 and became fully vested on March 9, 2026, reflecting performance-based compensation rather than a market purchase.

How many CONSTELLIUM SE shares does Nicolas Brun own after these Form 4 transactions?

After the reported transactions, Nicolas Brun directly holds 127,176 ordinary shares of Constellium SE. This reflects the net result of selling 17,701 shares and receiving 23,710 vested performance-based shares on March 9, 2026.

Were the CSTM insider share sales by Nicolas Brun part of multiple trades?

Yes. The filing states the reported sale price is a weighted average from multiple trades executed between $24.63 and $24.72. Brun has committed to provide trade-by-trade details to the company, shareholders, or regulators upon request.