Spero Therapeutics, Inc. (SPRO) has 20 known insider and institutional holders on record. The largest holder is GSK PLC with 9,190,606 shares. Other notable holders include Aquilo Capital, L.P. and Aquilo Capital Management, LLC.
Over the last 12 months, insiders have made 18 transactions in SPRO stock — 11 buys (valued at $1.42M) and 7 sells (valued at $335.28K). Insider buying has outpaced selling during this period, which may signal confidence in the company's prospects.
SPRO Insider Ownership
Top Holder
GSK PLC
9,190,606 shares
Buys (12 mo)
11
$1.42M value
Sells (12 mo)
7
$335.28K value
12-Month Transaction Activity
Top Insider Holders
| # |
Name |
Role |
Shares Owned |
Last Filed |
Relative Size |
| 1 |
Gsk Plc |
Director |
9,190,606 |
2022-11-14 |
|
| 2 |
Aquilo Capital, L.p. |
Director |
5,321,231 |
2022-04-28 |
|
| 3 |
Aquilo Capital Management, Llc |
10 Percent Owner |
3,419,435 |
2022-09-26 |
|
| 4 |
Glaxosmithkline Plc |
10 Percent Owner |
1,934,006 |
2018-07-17 |
|
| 5 |
Shukla Sath |
CEO & President |
1,892,216 |
2025-02-05 |
|
| 6 |
Graham Holdings Co |
10 Percent Owner |
1,428,094 |
2015-11-02 |
|
| 7 |
Rajavelu Esther |
See Remarks |
1,012,091 |
2026-02-09 |
|
| 8 |
Hamed Kamal |
Chief Medical Officer |
816,192 |
2024-02-05 |
|
| 9 |
Keutzer Timothy |
Chief Operating Officer |
742,506 |
2026-02-09 |
|
| 10 |
Mahadevia Ankit |
Director |
703,294 |
2025-09-03 |
|
| 11 |
Joseph Tamara L |
Chief Legal Officer |
562,521 |
2024-02-05 |
|
| 12 |
Deshpande Milind |
Director |
91,454 |
2025-06-16 |
|
| 13 |
Tregoning Kathleen |
Director |
75,000 |
2025-06-16 |
|
| 14 |
Smith Cynthia |
Director |
75,000 |
2025-06-16 |
|
| 15 |
Jackson Scott Thomas |
Director |
75,000 |
2025-06-16 |
|
| 16 |
Thomas Frank E |
Director |
75,000 |
2025-06-16 |
|
| 17 |
Pottage John C Jr |
Director |
75,000 |
2025-06-16 |
|
| 18 |
Vink Patrick V.j.j. |
Director |
75,000 |
2025-06-16 |
|
| 19 |
Sendek Joel |
Chief Financial Officer |
65,000 |
2019-01-02 |
|
| 20 |
Larkin Cristina |
Chief Operating Officer |
53,190 |
2022-02-03 |
|
Recent Transactions (last 12 months)
| Date |
Name |
Role |
Type |
Shares |
Price |
Value |
| 2026-02-06 |
Rajavelu Esther |
See Remarks |
Informative Sell |
50,816 |
$2.36 |
$119.93K |
| 2026-02-06 |
Keutzer Timothy |
Chief Operating Officer |
Informative Sell |
18,652 |
$2.36 |
$44.02K |
| 2026-02-04 |
Keutzer Timothy |
Chief Operating Officer |
Informative Sell |
3,471 |
$2.24 |
$7.78K |
| 2026-02-03 |
Keutzer Timothy |
Chief Operating Officer |
Informative Sell |
24,224 |
$2.14 |
$51.84K |
| 2026-02-02 |
Keutzer Timothy |
Chief Operating Officer |
RSU Award |
137,000 |
$2.23 |
$305.51K |
| 2026-02-02 |
Rajavelu Esther |
See Remarks |
RSU Award |
498,000 |
$2.23 |
$1.11M |
| 2025-11-07 |
Rajavelu Esther |
See Remarks |
Informative Sell |
40,270 |
$2.37 |
$95.44K |
| 2025-08-28 |
Keutzer Timothy |
Chief Operating Officer |
Informative Sell |
1,695 |
$1.97 |
$3.34K |
| 2025-08-28 |
Mahadevia Ankit |
Director |
Informative Sell |
6,572 |
$1.97 |
$12.95K |
| 2025-06-12 |
Tregoning Kathleen |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Mahadevia Ankit |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Smith Cynthia |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Jackson Scott Thomas |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Vink Patrick V.j.j. |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Deshpande Milind |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Pottage John C Jr |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-06-12 |
Thomas Frank E |
Director |
RSU Award |
20,000 |
- |
- |
| 2025-05-02 |
Rajavelu Esther |
See Remarks |
RSU Award |
185,000 |
- |
- |
