13D Filings
Arcellx, Inc.
ACLX
Amendment
Ownership

6.90%

Total Shares

3,997,132

Issuer CIK

1786205

CUSIP

03940C100

Event Date

Feb 26, 2025

Accepted

Feb 27, 2025, 04:23 PM

Reporting Persons (1)
NameType% of ClassAggregateSole VotingShared Voting
Rami Elghandour
Individual
6.90%3,997,1323,997,1320
Disclosure Items (3)

Security Title

Common stock, par value $0.001 per share

Issuer Name

Arcellx, Inc.

Issuer Address

800 Bridge Parkway, Redwood City, CA, 94065

The last paragraph of Item 3 of Schedule 13D is hereby deleted and replaced with the following: On February 27, 2025, the compensation committee of the Issuer's board of directors determined that performance criteria under each of the Reporting Person's June 9, 2021 award and January 3, 2023 award were partially satisfied (measured as of December 31, 2024), such that the awards vested as to 668,416 and 347,255 shares, respectively. The unvested portions of the awards remain outstanding. The vested shares will be issued to the Reporting Person as provided in the applicable award agreements.

Percentage of Class

Item 5 of Schedule 13D is hereby amended and restated as follows: As of the date of this Schedule 13D/A, the Reporting Person beneficially owns an aggregate of 3,997,132 shares of common stock, or 6.9% of the Issuer's outstanding shares of common stock. The beneficial ownership percentages used in this Schedule are calculated based on the sum of (i) 54,944,012 shares of common stock outstanding as of February 27, 2025, based on information provided by the Issuer, and (ii) 2,832,275 shares of common stock issuable pursuant to options held directly by the Reporting Person exercisable within 60 days of February 27, 2025.

Number of Shares

The Reporting Person has sole voting and dispositive power with respect to the securities covered by this Schedule.

Transactions

During the past 60 days, the Reporting Person effected the following transactions in the Issuer's Common Stock, in broker-assisted sales to satisfy tax withholding obligations in connection with the vesting of restricted stock units: (i) on January 3, 2025, the Reporting Person sold 15,112 shares of Common Stock at a weighted-average sales price of $79.55, (ii) on January 6, 2025, the Reporting Person sold 15,111 shares of Common Stock at a weighted-average sales price of $77.17, (iii) on January 7, 2025, the Reporting Person sold 16,474 shares of Common Stock at a weighted-average sales price of $75.53, (iv) on January 8, 2025, the Reporting Person sold 13,837 shares of Common Stock at a weighted-average sales price of $73.69 and (v) on February 26, 2025, the Reporting Person sold 38,300 shares of Common Stock at a weighted-average sales price of $62.02.

Shareholders

No person is known to the Reporting Person to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, any securities covered by this Schedule.

Date of 5% Ownership

Not Applicable.

Arcellx, Inc. — Schedule 13D | 13D Filings