Arcellx, Inc. — Director's Dealing 2025

Jan 11, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Arcellx, Inc. (ACLX)
CIK: 0001786205
Period of Report: 2025-01-07

Reporting Person: Gilson Michelle (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-01-03	Common Stock	M	15339	—	Acquired	38834	Direct
2025-01-07	Common Stock	S	3128	$74.4268	Disposed	24463	Direct
2025-01-07	Common Stock	S	1546	$75.2333	Disposed	22917	Direct
2025-01-07	Common Stock	S	2251	$76.6422	Disposed	20666	Direct
2025-01-07	Common Stock	S	2327	$77.0605	Disposed	18339	Direct
2025-01-07	Common Stock	S	4760	$75.5283	Disposed	13579	Direct
2025-01-08	Common Stock	S	3997	$73.6929	Disposed	9582	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-01-03	Restricted Stock Unit	$	M	15339	Disposed		Common Stock (15339)	Direct

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, 2025.

F2: The sale of shares reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan entered into by the Reporting Person on December 18, 2023 and subsequently modified March 27, 2024.

F3: Represents the weighted average share price of an aggregate total of 3,128 shares sold in the price range of $73.80 to $74.74 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: Represents the weighted average share price of an aggregate total of 1,546 shares sold in the price range of $74.85 to $75.73 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.

F5: Represents the weighted average share price of an aggregate total of 2,251 shares sold in the price range of $75.93 to $76.91 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.

F6: Represents the weighted average share price of an aggregate total of 2,327 shares sold in the price range of $76.93 to $77.16 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.

F7: Represents a broker-assisted sale to satisfy the Reporting Person's tax withholding obligations in connection with the vesting of restricted stock units.

F8: 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.

F9: Subject to the Reporting Person continuing to be a Service Provider (as defined in the Issuer's 2022 Equity Incentive Plan) through each applicable vesting date, one-third (1/3rd) of the RSUs subject to the award will vest each year following the RSU Grant Date on the same day of the month as the RSU Grant Date (or, if there is no corresponding day in a particular month, then the last day of the month) over three (3) years. "RSU Grant Date" shall mean January 3, 2023.