Arcellx, Inc. — Director's Dealing 2026

Feb 27, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Arcellx, Inc. (ACLX)
CIK: 0001786205
Period of Report: 2026-02-27

Reporting Person: Elghandour Rami (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-01-02	Common Stock	M	55459	—	Acquired	673378	Direct
2026-01-03	Common Stock	M	53098	—	Acquired	726476	Direct
2026-01-06	Common Stock	M	55991	—	Acquired	782467	Direct
2026-02-27	Common Stock	S	89916	$113.9204	Disposed	276051	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	198000	Indirect
Common Stock	218500	Indirect

Footnotes

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 89,916 shares sold in the price range of $113.83 to $114.25 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.

F4: Shares held by a spousal lifetime access non-grantor trust, of which the Reporting Person's spouse is the beneficiary and for which the Reporting Person may be deemed to have Section 16 beneficial ownership. The Reporting Person disclaims beneficial ownership except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such shares for Section 16 or any other purpose.

F5: Shares held by a spousal lifetime access non-grantor trust of which the Reporting Person is a beneficiary and for which the Reporting Person may be deemed to have Section 16 beneficial ownership. The Reporting Person disclaims beneficial ownership except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such shares for Section 16 or any other purpose.