BlackRock (CENX holder) discloses 9.5% beneficial stake in Century Co shares

Rhea-AI Filing Summary

BlackRock, Inc. filed an amended ownership report on Century Co. common stock. BlackRock reports beneficial ownership of 9,417,581 shares of Century Co. common stock, representing 9.5% of the class. Of these, 9,304,596 shares carry sole voting power and all 9,417,581 shares are subject to sole dispositive power, with no shared voting or dispositive power reported.

The filing states this position reflects securities beneficially owned, or deemed beneficially owned, by certain BlackRock business units, excluding other units whose holdings are disaggregated under SEC guidance. Various underlying clients have rights to dividends and sale proceeds in these shares, but no single client has more than five percent of Century Co.’s outstanding common stock.

Key Figures

Beneficially owned shares: 9,417,581 shares Ownership percentage: 9.5% Sole voting power: 9,304,596 shares +3 more

6 metrics

Beneficially owned shares 9,417,581 shares Century Co common stock reported as beneficially owned by BlackRock business units

Ownership percentage 9.5% Percent of Century Co common stock class reported as owned by BlackRock

Sole voting power 9,304,596 shares Century Co shares over which BlackRock has sole power to vote or direct the vote

Shared voting power 0 shares Century Co shares over which BlackRock has shared power to vote

Sole dispositive power 9,417,581 shares Century Co shares over which BlackRock has sole power to dispose

Shared dispositive power 0 shares Century Co shares over which BlackRock has shared power to dispose

Key Terms

beneficially owned, Sole Voting Power, dispositive power, percent of class

4 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned, by certain business units"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Sole Voting Power financial

"5 | Sole Voting Power 9,304,596.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

dispositive power financial

"Sole Dispositive Power 9,417,581.00 8 | Shared Dispositive Power 0.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

percent of class financial

"Percent of class: 9.5 %"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/27/2026 - 04:28 PM Accepted by SEC EDGAR 07/27/2026 - 04:25 PM Learn about SEC filing dates

FAQ

What percentage of Century Co (CENX) does BlackRock currently report owning?

BlackRock reports beneficial ownership of 9.5% of Century Co’s common stock. This stake is based on 9,417,581 shares reported as beneficially owned by certain BlackRock business units under SEC Schedule 13G/A rules.

How many Century Co (CENX) shares does BlackRock report as beneficially owned?

BlackRock reports beneficial ownership of 9,417,581 Century Co common shares. These shares are attributed to specific BlackRock business units, with separate units’ holdings disaggregated under applicable SEC guidance and therefore not included in this total.

What voting power does BlackRock have over its Century Co (CENX) holdings?

BlackRock reports 9,304,596 Century Co shares with sole voting power and 0 shares with shared voting power. This means the relevant BlackRock business units alone can vote or direct the vote on those 9,304,596 shares.

What dispositive power does BlackRock report over Century Co (CENX) shares?

BlackRock reports sole dispositive power over 9,417,581 Century Co shares and 0 shares with shared dispositive power. Sole dispositive power means those BlackRock business units can decide independently whether to sell or otherwise dispose of those shares.

Do BlackRock’s underlying clients in Century Co (CENX) hold more than 5% individually?

The filing states that various persons have rights to dividends and sale proceeds from the Century Co shares, but that no single person’s interest in Century Co common stock exceeds five percent of the total outstanding common shares.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

CENTURY ALUMINUM CO

(Name of Issuer)

Common Stock

(Title of Class of Securities)

156431108

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 156431108

1

Names of Reporting Persons

BlackRock, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 9,304,596.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,417,581.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,417,581.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.5 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: CENTURY ALUMINUM CO
(b)	Address of issuer's principal executive offices: 1 SOUTH WACKER DRIVE, SUITE 1000 CHICAGO IL 60606
Item 2.
(a)	Name of person filing: BlackRock, Inc. In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by certain business units (collectively, the "Reporting Business Units") of BlackRock, Inc. and its subsidiaries and affiliates. It does not include securities, if any, beneficially owned by other business units whose beneficial ownership of securities are disaggregated from that of the Reporting Business Units in accordance with such release.
(b)	Address or principal business office or, if none, residence: BlackRock, Inc., 50 Hudson Yards New York, NY 10001
(c)	Citizenship: See Item 4 of Cover Page
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 156431108
Item 4.	Ownership
(a)	Amount beneficially owned: 9417581
(b)	Percent of class: 9.5 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 9304596
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 9417581
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Various persons have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of the common stock of CENTURY ALUMINUM CO. No one person's interest in the common stock of CENTURY ALUMINUM CO is more than five percent of the total outstanding common shares.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit 99
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

BlackRock, Inc.

Signature:	Spencer Fleming
Name/Title:	Managing Director
Date:	07/27/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7