Christopher Heery - 12 Jan 2026 Form 4 Insider Report for Arcellx, Inc. (ACLX)

Role: CHIEF MEDICAL OFFICER
Signature: /s/ Michelle Gilson, as Attorney-in-Fact
Issuer symbol: ACLX
Transactions as of: 12 Jan 2026
Net transactions value: -$393,286
Form type: 4
Filing time: 12 Jan 2026, 21:32:13 UTC
Previous filing: 06 Jan 2026
Next filing: 13 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Heery Christopher	CHIEF MEDICAL OFFICER	C/O ARCELLX, INC., 800 BRIDGE PARKWAY, REDWOOD CITY	/s/ Michelle Gilson, as Attorney-in-Fact	12 Jan 2026	0001789632

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ACLX	Common Stock	Options Exercise	$0	+13,021	+2192%	$0.000000	13,615	02 Jan 2026	Direct	F1
transaction	ACLX	Common Stock	Sale	$393,286	-6,131	-14%	$64.15	37,068	12 Jan 2026	Direct	F2, F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	Represents a broker-assisted sale to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.
F3	Represents the weighted average share price of an aggregate total of 6,131 shares sold in the price range of $64.14112 to $64.4463 by the Reporting Person. The Reporting Person undertakes to provide upon request by the Commission staff, the issuer or a security holder of the issuer, full information regarding the number of shares sold at each separate price.