BlackRock reports 8.2% stake in Century Co

CENTURY CO Schedule 13G/A reports that BlackRock, Inc. beneficially owned 8,136,119 shares of CENTURY CO common stock, representing 8.2% of the class.

Rhea-AI Filing Summary

CENTURY CO Schedule 13G/A reports that BlackRock, Inc. beneficially owned 8,136,119 shares of CENTURY CO common stock, representing 8.2% of the class. The cover lists CUSIP 156431108 and an issuer address in Chicago. The filing shows sole voting power of 8,044,315 shares and sole dispositive power of 8,136,119. The amendment is signed by Spencer Fleming on 04/24/2026.

Insights

Institutional Ownership Specialist

BlackRock reports an 8.2% passive stake in CENTURY CO via a 13G/A amendment.

The filing lists 8,136,119 shares beneficially owned and quantifies voting and dispositive powers. This is a disclosure of institutional ownership levels, not an active acquisition statement.

Stake size and voting power are relevant for governance monitoring; subsequent SEC filings may show changes in position or voting intentions.

Securities Compliance Analyst

The amendment clarifies reporting units and includes customary exhibits.

The cover cites aggregation across Reporting Business Units per SEC Release No. 34-39538 and attaches Exhibit 24 and Exhibit 99. The statement disaggregates other business-unit holdings consistent with that release.

Filing appears routine; stakeholders should note the signature date 04/24/2026 for the amendment's execution.

Key Figures

Beneficially owned shares: 8,136,119 shares Percent of class: 8.2% Sole voting power: 8,044,315 shares +4 more

7 metrics

Beneficially owned shares 8,136,119 shares Amount beneficially owned reported on Schedule 13G/A

Percent of class 8.2% Percent of class reported on Schedule 13G/A

Sole voting power 8,044,315 shares Sole power to vote or to direct the vote

Sole dispositive power 8,136,119 shares Sole power to dispose or direct disposition

CUSIP 156431108 Identifier for CENTURY CO common stock

Amendment signature date 04/24/2026 Signature date on the amendment

As-of date shown 03/31/2026 Date appearing near cover page CUSIP line

Key Terms

Schedule 13G/A, beneficially owned, sole dispositive power, Reporting Business Units

4 terms

Schedule 13G/A regulatory

"Amendment No. 5 ) CENTURY CO Common Stock"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficially owned financial

"Amount beneficially owned: 8136119"

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 dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 8136119"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Reporting Business Units regulatory

"securities beneficially owned ... by certain business units (collectively, the "Reporting Business Units")"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does BlackRock hold in CENTURY CO (CENX)?

BlackRock beneficially owned 8,136,119 shares, representing 8.2% of the class. The filing reports voting and dispositive powers and cites CUSIP 156431108.

What voting power does BlackRock report on the Schedule 13G/A?

The filing shows BlackRock has sole voting power for 8,044,315 shares. It also reports sole dispositive power for 8,136,119 shares, per the amendment signed on 04/24/2026.

Is this a passive 13G filing or an active acquisition disclosure?

This is an amended Schedule 13G/A, used for passive institutional investors under SEC rules. It reflects beneficial ownership reported by BlackRock's Reporting Business Units, per the filing text.

What date and signature appear on the amendment?

The amendment is signed by Spencer Fleming, Managing Director with a signature date of 04/24/2026. The cover lists an as-of date of 03/31/2026 near the CUSIP line.

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

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Accepted by SEC EDGAR 04/24/2026 - 04:11 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 5)

CENTURY ALUMINUM CO

(Name of Issuer)

Common Stock

(Title of Class of Securities)

156431108

(CUSIP Number)

03/31/2026

(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 8,044,315.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 8,136,119.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,136,119.00

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)

8.2 %

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: 8136119
(b)	Percent of class: 8.2 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 8044315
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 8136119
	(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:	04/24/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7