According to recent filings covering the 90 days ending December 12, 2025, the three most significant insider holders at Arcellx are Director Jill Carroll (1.48Mn shares), See Remarks Rami Elghandour (617.92K shares), Chief Financial Officer Michelle Gilson (8.47K shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Enterprise Associates 15, L.P. New | 4,745,262 | 22 Dec, 2022 | |
| Partners 15, L.P. Nea | 4,745,262 | 22 Dec, 2022 | |
| Holdings A/S Novo | 4,016,878 | 09 Feb, 2022 | |
| Lewis T Williams | 2,095,114 | 09 Feb, 2022 | |
| One Capital Management, Llc Sr | 1,658,780 | 15 May, 2023 | |
| Jill Carroll | 1,479,148 | 25 Mar, 2024 | |
| Rami Elghandour | See Remarks | 617,919 | 29 Aug, 2025 |
| David Charles Lubner | 21,659 | 09 Feb, 2022 | |
| Michelle Gilson | Chief Financial Officer | 8,466 | 15 Oct, 2025 |
| Ali Behbahani | 4,631 | 14 Aug, 2025 | |
| Christopher Heery | Chief Medical Officer | 284 | 17 Nov, 2025 |
| Mohamad Makhzoumi | 283 | 22 Dec, 2022 | |
| Peter W. Sonsini | 12 | 22 Dec, 2022 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 17 Nov, 2025 | Christopher Heery | Common Stock | D | 340 | $90.00 | 284 | D | S |
| 15 Oct, 2025 | Michelle Gilson | Common Stock | D | 5,364 | $91.04 | 8,466 | D | S |
| 03 Oct, 2025 | Michelle Gilson | Common Stock | D | 4,882 | $86.00 | 14,894 | D | S |
| 06 Oct, 2025 | Michelle Gilson | Common Stock | D | 1,064 | $86.22 | 13,830 | D | S |
| 30 Sep, 2025 | Christopher Heery | Common Stock | D | 5,300 | $80.55 | 16,358 | D | S |
| 30 Sep, 2025 | Christopher Heery | Common Stock | D | 14,204 | $81.46 | 2,154 | D | S |
| 30 Sep, 2025 | Christopher Heery | Common Stock | D | 1,530 | $82.20 | 624 | D | S |
| 29 Sep, 2025 | Christopher Heery | Common Stock | D | 73 | $80.16 | 21,658 | D | S |
| 26 Sep, 2025 | Christopher Heery | Common Stock | D | 12,396 | $80.12 | 21,731 | D | S |
| 18 Sep, 2025 | Christopher Heery | Common Stock | D | 3,343 | $80.01 | 34,427 | D | S |
| 19 Sep, 2025 | Christopher Heery | Common Stock | D | 300 | $80.00 | 34,127 | D | S |
| 28 Aug, 2025 | Rami Elghandour | Common Stock | D | 546,938 | $70.25 | 617,919 | D | F |
| 28 Aug, 2025 | Rami Elghandour | - | - | 617,919 | D | |||
| 12 Aug, 2025 | Ali Behbahani | - | - | 1,925 | D | |||
| 12 Aug, 2025 | Ali Behbahani | Common Stock | A | 1,586 | $0.00 | 1,925 | D | J |
| 12 Aug, 2025 | Ali Behbahani | Common Stock | A | 2,621 | $0.00 | 2,706 | I | J |
| 12 Aug, 2025 | Ali Behbahani | - | - | 2,706 | I | |||
| 10 Jun, 2025 | Kavita Patel | Common Stock | A | 1,500 | $6.66 | 1,500 | D | M |
| 10 Jun, 2025 | Kavita Patel | Common Stock | D | 1,500 | $67.36 | 0 | D | S |
| 23 May, 2025 | Michelle Gilson | - | - | 32,011 | D |