Spero Therapeutics, Inc. (SPRO) Insider Ownership

Historic Insider Ownership Trends

As of March 23, 2026, the three largest insider holders of SPRO are Capital Management, Llc Aquilo (TenPercentOwner, 3.42Mn shares), Sath Shukla (Ceo President, 1.74Mn shares), Esther Rajavelu (See Remarks, 1.01Mn shares).

Top Direct Holders

Insider ownership data is derived from the last 60 months of Form 4 SEC filings.
Holder Position Shares (Direct) Shares (Indirect) Report Date
Capital Management, Llc Aquilo 0 3,419,435 26 Sep, 2022
Sath Shukla Ceo President 1,736,883 0 05 Feb, 2025
Esther Rajavelu See Remarks 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 703,294 0 02 Sep, 2025
Cynthia Smith 75,000 0 12 Jun, 2025
Kathleen Tregoning 75,000 0 12 Jun, 2025
Frank E Thomas 75,000 0 12 Jun, 2025
Patrick V.J.J. Vink 75,000 0 12 Jun, 2025
Scott Thomas Jackson 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.

Recent Insider Transactions

Detailed insider trading activity based on Form 4 SEC filings.
Download Data
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 Esther Rajavelu Common Stock A 249,000 $0.00 1,118,450 D A
02 Feb, 2026 Timothy Keutzer Common Stock A 68,000 $0.00 807,744 D A
02 Feb, 2026 Timothy Keutzer Common Stock D 18,891 $2.20 788,853 D S
02 Feb, 2026 Esther Rajavelu Common Stock D 18,442 $2.20 1,100,008 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 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
12 Jun, 2025 Cynthia Smith Common Stock A 20,000 $0.00 75,000 D A
12 Jun, 2025 Scott Thomas Jackson Common Stock A 20,000 $0.00 75,000 D A
12 Jun, 2025 Frank E Thomas Common Stock A 20,000 $0.00 75,000 D A
12 Jun, 2025 Kathleen Tregoning Common Stock A 20,000 $0.00 75,000 D A