T. Rowe Price (ACLX) reports 18.3% beneficial stake in Arcellx

Rhea-AI Filing Summary

T. Rowe Price Investment Management, Inc. reported beneficial ownership of 10,560,425 shares of Arcellx Inc.18.3% of the class as of the event date December 31, 2025.

The firm has sole power to vote 10,266,287 shares and sole power to dispose of 10,554,934 shares, with no shared voting or dispositive power. It states the shares were acquired and are held in the ordinary course of business, not to influence control of Arcellx.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

ARCELLX INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

03940C100

(CUSIP Number)

12/31/2025

(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)

SCHEDULE 13G

CUSIP No. 03940C100

1

Names of Reporting Persons

T. Rowe Price Investment Management, 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

MARYLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 10,266,287.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 10,554,934.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,560,425.00

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)

18.3 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ARCELLX INC
(b)	Address of issuer's principal executive offices: 800 BRIDGE PARKWAY, REDWOOD CITY, CA, 94065
Item 2.
(a)	Name of person filing: T. Rowe Price Investment Management, Inc.
(b)	Address or principal business office or, if none, residence: 1307 Point Street, Baltimore, MD 21231
(c)	Citizenship: Maryland
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 03940C100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 10560425
(b)	Percent of class: 18.3 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 10266287
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 10554934
	(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.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
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. T. Rowe Price Investment Management, Inc. hereby declares and affirms that the filing of Schedule 13G shall not be construed as an admission that Price Investment Management is the beneficial owner of the securities referred to, which beneficial ownership is expressly denied.

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.

T. Rowe Price Investment Management, Inc.

Signature:	Ellen York
Name/Title:	Vice President
Date:	02/17/2026

FAQ

How many Arcellx (ACLX) shares does T. Rowe Price Investment Management own?

T. Rowe Price Investment Management reports beneficial ownership of 10,560,425 Arcellx common shares. This stake represents a significant holding and is disclosed in a Schedule 13G/A, which is used for institutional investors with a generally passive investment intent.

What percentage of Arcellx (ACLX) does T. Rowe Price Investment Management hold?

T. Rowe Price Investment Management holds 18.3% of Arcellx’s common stock. This percentage is based on the shares outstanding referenced in the filing and reflects a sizable institutional position that must be reported under U.S. securities ownership disclosure rules.

Does T. Rowe Price Investment Management control Arcellx (ACLX) through this stake?

T. Rowe Price Investment Management states the Arcellx shares were acquired and are held in the ordinary course of business. It affirms they were not acquired for the purpose of changing or influencing control of Arcellx, consistent with a passive Schedule 13G filing.

What voting power does T. Rowe Price Investment Management have over Arcellx (ACLX) shares?

The firm reports sole voting power over 10,266,287 shares of Arcellx common stock and no shared voting power. This means it alone can vote those shares, subject to any internal or client mandates, as disclosed in the Schedule 13G/A.

What dispositive power does T. Rowe Price Investment Management have in Arcellx (ACLX)?

T. Rowe Price Investment Management reports sole dispositive power over 10,554,934 shares and no shared dispositive power. Sole dispositive power indicates authority to decide whether and when to sell those shares, consistent with its role as an investment manager.

Why did T. Rowe Price Investment Management file a Schedule 13G/A for Arcellx (ACLX)?

The Schedule 13G/A was filed because its Arcellx holdings exceeded 5% of the company’s common stock. The firm certifies that the securities were acquired and are held in the ordinary course of business, not to influence control, which aligns with 13G passive reporting.