Arcellx's top three insider shareholders as of March 23, 2026 are Partners 15, L.P. Nea (TenPercentOwner, 4.75Mn shares), Enterprise Associates 15, L.P. New (TenPercentOwner, 4.75Mn shares), Holdings A/S Novo (TenPercentOwner, 4.02Mn shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Enterprise Associates 15, L.P. New | 4,745,262 | 0 | 22 Dec, 2022 | |
| Partners 15, L.P. Nea | 0 | 4,745,262 | 22 Dec, 2022 | |
| Holdings A/S Novo | 4,016,878 | 0 | 09 Feb, 2022 | |
| Lewis T Williams | 0 | 2,095,114 | 09 Feb, 2022 | |
| One Capital Management, Llc Sr | 0 | 1,658,780 | 15 May, 2023 | |
| Jill Carroll | 0 | 1,479,148 | 25 Mar, 2024 | |
| Rami Elghandour | See Remarks | 174,887 | 0 | 04 Mar, 2026 |
| Michelle Gilson | Chief Financial Officer | 28,938 | 0 | 19 Mar, 2026 |
| Christopher Heery | Chief Medical Officer | 23,749 | 0 | 14 Jan, 2026 |
| David Charles Lubner | 21,659 | 0 | 20 Jan, 2026 | |
| Ali Behbahani | 1,925 | 2,706 | 14 Aug, 2025 | |
| Mohamad Makhzoumi | 283 | 0 | 22 Dec, 2022 | |
| Peter W. Sonsini | 0 | 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 Mar, 2026 | Michelle Gilson | Common Stock | D | 5,000 | $0.00 | 28,938 | D | G |
| 04 Mar, 2026 | Rami Elghandour | Common Stock | D | 101,164 | $0.00 | 174,887 | D | G |
| 02 Jan, 2026 | Rami Elghandour | Common Stock | A | 55,459 | $0.00 | 673,378 | D | M |
| 03 Jan, 2026 | Rami Elghandour | Common Stock | A | 53,098 | $0.00 | 726,476 | D | M |
| 06 Jan, 2026 | Rami Elghandour | Common Stock | A | 55,991 | $0.00 | 782,467 | D | M |
| 27 Feb, 2026 | Rami Elghandour | Common Stock | D | 89,916 | $113.92 | 276,051 | D | S |
| 06 Jan, 2026 | Michelle Gilson | Common Stock | A | 20,530 | $0.00 | 64,832 | D | M |
| 25 Feb, 2026 | Michelle Gilson | Common Stock | D | 11,219 | $113.82 | 33,938 | D | S |
| 03 Jan, 2026 | Michelle Gilson | Common Stock | A | 15,340 | $0.00 | 44,302 | D | M |
| 19 Feb, 2026 | Michelle Gilson | Common Stock | D | 2,879 | $67.73 | 50,662 | D | S |
| 19 Feb, 2026 | Michelle Gilson | Common Stock | D | 5,405 | $68.57 | 45,257 | D | S |
| 19 Feb, 2026 | Michelle Gilson | Common Stock | D | 100 | $69.38 | 45,157 | D | S |
| 02 Jan, 2026 | Michelle Gilson | Common Stock | A | 20,496 | $0.00 | 28,962 | D | M |
| 17 Feb, 2026 | Michelle Gilson | Common Stock | D | 7,141 | $69.21 | 57,691 | D | S |
| 17 Feb, 2026 | Michelle Gilson | Common Stock | D | 4,150 | $70.01 | 53,541 | D | S |
| 11 Feb, 2026 | Rami Elghandour | Common Stock | D | 198,000 | $0.00 | 365,967 | D | G |
| 11 Feb, 2026 | Rami Elghandour | Common Stock | D | 218,500 | $0.00 | 563,967 | D | G |
| 20 Jan, 2026 | David Charles Lubner | Common Stock | A | 6,000 | $6.28 | 27,659 | D | M |
| 20 Jan, 2026 | David Charles Lubner | Common Stock | D | 6,000 | $75.00 | 21,659 | D | S |
| 20 Jan, 2026 | David Charles Lubner | Stock Option (right to buy) | D | 6,000 | $0.00 | 59,405 | D | M |