Arcellx (NASDAQ: ACLX) CMO reports RSU vesting, tax sale of shares

Rhea-AI Filing Summary

Arcellx, Inc. chief medical officer Christopher Heery reported equity award activity and a related share sale. On 01/06/2026, he acquired 13,064 shares of common stock at $0.00 per share through the vesting and settlement of previously reported restricted stock units, each RSU converting into one share. On 01/14/2026, he sold 5,882 shares of common stock at a weighted average price of $68.5136 per share in a broker-assisted transaction to cover tax withholding obligations tied to that RSU vesting.

After these transactions, Heery directly held 23,749 shares of Arcellx common stock.

Insider Trade Summary

Net Seller: 5,882 shares ($402,997)

Net Sell 2 txns

Insider Heery Christopher

Role CHIEF MEDICAL OFFICER

Sold 5,882 shs ($403K)

Type	Security	Shares	Price	Value
Sale	Common Stock	5,882	$68.5136	$403K
Exercise	Common Stock	13,064	$0.00	--

Holdings After Transaction: Common Stock — 23,749 shares (Direct)

Footnotes (1)

1. Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock. Vesting of these RSUs previously reported in the Form 4 filed January 6, 2026. Represents a broker-assisted sale to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units. The price reported reflects the weighted average sales price. These shares were sold in multiple transactions at prices that were not available from the broker at the time of filing. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price.

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^*

Heery Christopher

(Last) (First) (Middle)

C/O ARCELLX, INC.

800 BRIDGE PARKWAY

(Street)

REDWOOD CITY CA 94065

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Arcellx, Inc. [ ACLX ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF MEDICAL OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
01/14/2026

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(1)	01/06/2026		M		13,064	A	$0	43,199	D
Common Stock	01/14/2026		S(2)		5,882	D	$68.5136(3)	23,749	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. Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock. Vesting of these RSUs previously reported in the Form 4 filed January 6, 2026.

2. Represents a broker-assisted sale to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

3. The price reported reflects the weighted average sales price. These shares were sold in multiple transactions at prices that were not available from the broker at the time of filing. The Reporting Person undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price.

	/s/ Michelle Gilson, as Attorney-in-Fact	01/14/2026
	** 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

Who is the reporting person in the Arcellx (ACLX) insider filing?

The reporting person is Christopher Heery, who serves as chief medical officer of Arcellx, Inc.

What equity award transaction did Arcellx (ACLX) CMO Christopher Heery report?

On 01/06/2026, Christopher Heery acquired 13,064 shares of Arcellx common stock at $0.00 per share upon settlement of previously reported restricted stock units, with each RSU representing one share.

How many Arcellx (ACLX) shares did the CMO sell and at what price?

On 01/14/2026, Christopher Heery sold 5,882 shares of Arcellx common stock at a weighted average price of $68.5136 per share.

Why did Arcellx (ACLX) CMO Christopher Heery sell shares on January 14, 2026?

The sale of 5,882 shares on 01/14/2026 was a broker-assisted sale to satisfy tax withholding obligations related to the vesting of restricted stock units.

How many Arcellx (ACLX) shares does the CMO hold after these transactions?

Following the reported transactions, Christopher Heery directly beneficially owned 23,749 shares of Arcellx common stock.

What does each RSU reported by Arcellx (ACLX) CMO represent?

Each restricted stock unit (RSU) reported represents a contingent right to receive one share of Arcellx’s common stock upon vesting and settlement.