Spero Therapeutics's three largest insider shareholders as of April 17, 2026 are Capital Management, Llc Aquilo (TenPercentOwner, 5.22Mn shares), Capital Management, Llc Aquilo (TenPercentOwner, 4.36Mn shares), Capital Management, Llc Aquilo (TenPercentOwner, 3.42Mn shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Capital Management, Llc Aquilo | - | 0 | 5,223,498 | 16 Mar, 2022 |
| Capital Management, Llc Aquilo | - | 0 | 4,358,030 | 01 Sep, 2021 |
| Capital Management, Llc Aquilo | - | 0 | 3,419,435 | 26 Sep, 2022 |
| Sath Shukla | Ceo President | 1,736,883 | 0 | 05 Feb, 2025 |
| Esther Rajavelu | Cfo Cbo | 1,012,091 | 0 | 09 Feb, 2026 |
| Kamal Hamed | Chief Medical Officer | 788,117 | 0 | 05 Feb, 2024 |
| Timothy Keutzer | Chief Operating Officer | 742,506 | 0 | 09 Feb, 2026 |
| Ankit Mahadevia | Ceo And President | 703,294 | 0 | 02 Sep, 2025 |
| Tamara L Joseph | Chief Legal Officer | 531,615 | 0 | 05 Feb, 2024 |
| Milind Deshpande | - | 91,454 | 0 | 12 Jun, 2025 |
| Patrick V.J.J. Vink | - | 75,000 | 0 | 12 Jun, 2025 |
| Scott Thomas Jackson | - | 75,000 | 0 | 12 Jun, 2025 |
| Kathleen Tregoning | - | 75,000 | 0 | 12 Jun, 2025 |
| Cynthia Smith | - | 75,000 | 0 | 12 Jun, 2025 |
| John C Jr Pottage | - | 75,000 | 0 | 12 Jun, 2025 |
| Cristina Larkin | Chief Operating Officer | 63,581 | 0 | 03 Feb, 2022 |
| David A. Melnick | Chief Medical Officer | 62,081 | 0 | 03 Feb, 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 |
|---|---|---|---|---|---|---|---|---|
| 06 Feb, 2026 | Timothy Keutzer | Common Stock | D | 18,652 | $2.36 | 742,506 | D | S |
| 06 Feb, 2026 | Esther Rajavelu | Common Stock | D | 37,101 | $2.36 | 1,062,907 | D | S |
| 06 Feb, 2026 | Esther Rajavelu | Common Stock | D | 50,816 | $2.36 | 1,012,091 | D | S |
| 02 Feb, 2026 | Timothy Keutzer | Common Stock | A | 68,000 | $0.00 | 807,744 | D | A |
| 02 Feb, 2026 | Esther Rajavelu | Common Stock | A | 249,000 | $0.00 | 1,118,450 | D | A |
| 02 Feb, 2026 | Esther Rajavelu | Common Stock | D | 18,442 | $2.20 | 1,100,008 | D | S |
| 02 Feb, 2026 | Timothy Keutzer | Common Stock | D | 18,891 | $2.20 | 788,853 | D | S |
| 02 Feb, 2026 | Esther Rajavelu | Stock Option (Right to Buy) | A | 498,000 | $0.00 | 498,000 | D | A |
| 03 Feb, 2026 | Timothy Keutzer | Common Stock | D | 24,224 | $2.14 | 764,629 | D | S |
| 04 Feb, 2026 | Timothy Keutzer | Common Stock | D | 3,471 | $2.24 | 761,158 | D | S |
| 02 Feb, 2026 | Timothy Keutzer | Stock Option (Right to Buy) | A | 137,000 | $0.00 | 137,000 | D | A |
| 07 Nov, 2025 | Esther Rajavelu | Common Stock | D | 40,270 | $2.37 | 869,450 | D | S |
| 28 Aug, 2025 | Ankit Mahadevia | Common Stock | D | 6,572 | $1.97 | 703,294 | D | S |
| 28 Aug, 2025 | Timothy Keutzer | Common Stock | D | 1,695 | $1.97 | 739,744 | D | S |
| 12 Jun, 2025 | Kathleen Tregoning | Common Stock | A | 20,000 | $0.00 | 75,000 | D | A |
| 12 Jun, 2025 | Cynthia Smith | Common Stock | A | 20,000 | $0.00 | 75,000 | D | A |
| 12 Jun, 2025 | Milind Deshpande | Common Stock | A | 20,000 | $0.00 | 91,454 | D | A |
| 12 Jun, 2025 | John C Jr Pottage | Common Stock | A | 20,000 | $0.00 | 75,000 | D | A |
| 12 Jun, 2025 | Patrick V.J.J. Vink | Common Stock | A | 20,000 | $0.00 | 75,000 | D | A |
| 12 Jun, 2025 | Ankit Mahadevia | Common Stock | A | 20,000 | $0.00 | 709,866 | D | A |