[Form 4] CENTURY ALUMINUM CO Insider Trading Activity

Rhea-AI Filing Summary

Century Aluminum executive Robert F. Hoffman, SVP, IT and Chief Accounting Officer, sold 10,529 shares of common stock in an open-market transaction on March 11, 2026 at a weighted average price of $56.51 per share, with trades ranging from $56.25 to $56.75.

After the sale, he directly owns 56,643 common shares, which include unvested RSUs granted under the company’s long-term incentive plans, and holds an additional 14.5476 shares indirectly through a 401(k) plan as reported by the plan trustee.

Insider Trade Summary

Net Seller: 10,529 shares ($594,994)

Net Sell 2 txns

Insider Hoffman Robert F

Role SVP, IT and CAO

Sold 10,529 shs ($595K)

Type	Security	Shares	Price	Value
Sale	Common Stock	10,529	$56.51	$595K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 56,643 shares (Direct); Common Stock — 14.548 shares (Indirect, By 401(k) plan)

Footnotes (1)

1. The price reported above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $56.25 to $56.75, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected. Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans. As reported by 401(k) plan trustee on March 11, 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^*

Hoffman Robert F

(Last) (First) (Middle)

C/O CENTURY ALUMINUM COMPANY

1 S. WACKER DRIVE, SUITE 1000

(Street)

CHICAGO IL 60606

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CENTURY ALUMINUM CO [ CENX ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP, IT and CAO

3. Date of Earliest Transaction (Month/Day/Year)
03/11/2026

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
Common Stock	03/11/2026		S		10,529	D	$56.51(1)	56,643(2)	D
Common Stock								14.5476(3)	I	By 401(k) plan

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 above reflects the weighted average sale price for the shares which were sold in multiple transactions at prices ranging from $56.25 to $56.75, inclusive. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the specific number of shares and prices at which the transactions were effected.

2. Includes unvested RSUs granted to the Reporting Person under the Issuer's Long-Term Incentive Plans.

3. As reported by 401(k) plan trustee on March 11, 2026.

Remarks:

	/s/ Paul Sharobeem, attorney-in-fact for Robert F. Hoffman	03/13/2026
	** 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 Century Aluminum (CENX) report for Robert F. Hoffman?

Century Aluminum reported that SVP, IT and Chief Accounting Officer Robert F. Hoffman sold 10,529 shares of common stock in an open-market transaction on March 11, 2026 at a weighted average price of $56.51 per share, based on multiple trades between $56.25 and $56.75.

At what price did the Century Aluminum (CENX) insider shares sell on March 11, 2026?

The reported weighted average sale price was $56.51 per share. The shares were sold in multiple transactions at individual prices ranging from $56.25 to $56.75, with the insider undertaking to provide detailed trade breakdowns upon request to regulators, the issuer or its security holders.

How many Century Aluminum (CENX) shares does Robert F. Hoffman hold after the sale?

Following the March 11, 2026 sale, Robert F. Hoffman directly holds 56,643 shares of Century Aluminum common stock and indirectly holds 14.5476 shares through a 401(k) plan, according to plan trustee reporting. The direct holdings include unvested RSUs under the company’s long-term incentive plans.

What role does Robert F. Hoffman hold at Century Aluminum (CENX)?

Robert F. Hoffman serves as Senior Vice President, IT and Chief Accounting Officer at Century Aluminum. His position is disclosed in the insider trading report, which details his open-market sale of 10,529 common shares and his remaining direct and indirect share ownership positions.

Are unvested RSUs included in Robert F. Hoffman’s Century Aluminum (CENX) holdings?

Yes. The filing notes that his reported direct holdings of 56,643 shares include unvested restricted stock units granted under Century Aluminum’s long-term incentive plans. This means his disclosed direct ownership figure reflects both vested common shares and unvested equity awards awarded by the company.

How are Robert F. Hoffman’s 401(k) holdings in Century Aluminum (CENX) reported?

The filing shows 14.5476 Century Aluminum shares held indirectly through a 401(k) plan. A footnote explains this amount was reported by the 401(k) plan trustee on March 11, 2026, indicating that the figure reflects plan records rather than a contemporaneous market transaction initiated by Hoffman.