Christopher Heery - 02 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
02 Jan 2026
Net transactions value
$0
Form type
4
Filing time
06 Jan 2026, 20:25:50 UTC
Previous filing
17 Nov 2025
Next filing
12 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 06 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 Options Exercise $0 +16,520 +121% $0.000000 30,135 03 Jan 2026 Direct
transaction ACLX Common Stock Options Exercise $0 +13,064 +43% $0.000000 43,199 06 Jan 2026 Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction ACLX Restricted Stock Unit Award $0 +67,708 $0.000000 67,708 02 Jan 2026 Common Stock 67,708 Direct F2, F3
transaction ACLX Restricted Stock Unit Options Exercise $0 -13,021 -50% $0.000000 13,021 02 Jan 2026 Common Stock 13,021 Direct F2, F4
transaction ACLX Restricted Stock Unit Options Exercise $0 -16,520 -100% $0.000000 0 03 Jan 2026 Common Stock 16,520 Direct F2, F5
transaction ACLX Restricted Stock Unit Options Exercise $0 -13,064 -25% $0.000000 39,194 06 Jan 2026 Common Stock 13,064 Direct F2, F6
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Includes 284 shares acquired under the Issuer's 2022 Employee Stock Purchase Plan on May 14, 2025, and 310 shares acquired under the Issuer's 2022 Employee Stock Purchase Plan on November 14, 2024.
F2 Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock.
F3 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-fourth (1/4th) 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 four (4) years. "RSU Grant Date" shall mean January 2, 2026.
F4 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 2, 2024.
F5 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.
F6 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-fourth (1/4th) 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 four (4) years. "RSU Grant Date" shall mean January 6, 2025.