SPERO THERAPEUTICS INC (SPRO) Top Institutional Shareholders
SPERO THERAPEUTICS INC (SPRO) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $47.63M in SPRO holdings during the latest filing period.
Gsk Plc is currently the largest disclosed institutional shareholder of SPRO tracked by InsiderSet, reporting ownership valued at approximately $21.51M in its March 31, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $19.39M, representing an estimated loss of -9.83% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 89% of the total disclosed SPRO value among the investors covered in this analysis. Major shareholders include Gsk Plc, Pfizer Inc, Vanguard Capital Management Llc, and several other long-term asset managers with concentrated positions in SPERO THERAPEUTICS INC (SPRO).
This page ranks the largest institutional SPRO shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
49
Total Reported Value
$47.63M
Largest Holder
Gsk Plc
Largest Position
$21.51M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
62
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Gsk Plc | 3.59% | 9,190,606 | $21,506,018 | $19,392,179 | -$2,113,839 | -9.83% | |
| Pfizer Inc | 2.31% | 2,362,348 | $5,504,271 | $4,984,554 | -$519,717 | -9.44% | |
| Vanguard Capital Management Llc | 0.00% | 1,799,880 | $4,211,719 | $3,797,747 | -$413,972 | -9.83% | |
| Renaissance Technologies LLC | Jim Simons | 0.00% | 1,189,235 | $2,782,810 | $2,509,286 | -$273,524 | -9.83% |
| Alphabet Inc. | 0.05% | 889,979 | $2,082,551 | $1,877,856 | -$204,695 | -9.83% | |
| Two Sigma Investments, Lp | 0.00% | 885,631 | $2,072,377 | $1,868,681 | -$203,696 | -9.83% | |
| Geode Capital Management, Llc | 0.00% | 519,922 | $1,217,170 | $1,097,035 | -$120,135 | -9.87% | |
| Blackrock, Inc. | 0.00% | 433,202 | $1,013,693 | $914,056 | -$99,637 | -9.83% | |
| Anson Funds Management Lp | 0.13% | 421,956 | $987,377 | $890,327 | -$97,050 | -9.83% | |
| Citadel Advisors Llc | 0.00% | 376,458 | $880,912 | $794,326 | -$86,586 | -9.83% | |
| Susquehanna International Group, Llp | 0.00% | 333,115 | $779,489 | $702,873 | -$76,616 | -9.83% | |
| Vanguard Fiduciary Trust Co | 0.00% | 264,115 | $618,029 | $557,283 | -$60,746 | -9.83% | |
| State Street Corp | 0.00% | 214,751 | $502,517 | $453,125 | -$49,392 | -9.83% | |
| Ionic Capital Management Llc | 0.39% | 195,939 | $458,497 | $413,431 | -$45,066 | -9.83% | |
| Squarepoint Ops Llc | 0.00% | 194,301 | $454,664 | $409,975 | -$44,689 | -9.83% | |
| Marshall Wace, Llp | 0.00% | 157,072 | $367,547 | $331,422 | -$36,125 | -9.83% | |
| Northern Trust Corp | 0.00% | 120,984 | $283,103 | $255,276 | -$27,827 | -9.83% | |
| Bridgeway Capital Management, Llc | 0.01% | 114,800 | $268,632 | $242,228 | -$26,404 | -9.83% | |
| Jane Street Group, Llc | 0.00% | 106,345 | $248,847 | $224,388 | -$24,459 | -9.83% | |
| Shay Capital Llc | 0.02% | 70,354 | $164,628 | $148,447 | -$16,181 | -9.83% | |
| Point72 Asset Management, L.P. | 0.00% | 59,668 | $139,623 | $125,899 | -$13,724 | -9.83% | |
| Invesco Ltd. | 0.00% | 45,374 | $106,175 | $95,739 | -$10,436 | -9.83% | |
| Quadrature Capital Ltd | 0.00% | 40,128 | $93,900 | $84,670 | -$9,230 | -9.83% | |
| Capital Asset Advisory Services Llc | 0.00% | 32,548 | $92,436 | $68,676 | -$23,760 | -25.70% | |
| Omers Administration Corp | 0.00% | 39,400 | $92,196 | $83,134 | -$9,062 | -9.83% | |
| Verdad Advisers, Lp | 0.09% | 33,455 | $78,285 | $70,590 | -$7,695 | -9.83% | |
| Simplex Trading, Llc | 0.00% | 30,304 | $70,911 | $63,941 | -$6,970 | -9.83% | |
| Three Seasons Wealth, Llc | 0.03% | 30,000 | $70,200 | $63,300 | -$6,900 | -9.83% | |
| Dimensional Fund Advisors Lp | 0.00% | 29,768 | $69,207 | $62,810 | -$6,397 | -9.24% | |
| Charles Schwab Investment Management Inc | 0.00% | 28,565 | $66,842 | $60,272 | -$6,570 | -9.83% | |
| Vanguard Global Advisers, Llc | 0.00% | 25,446 | $59,544 | $53,691 | -$5,853 | -9.83% | |
| Schonfeld Strategic Advisors Llc | 0.00% | 20,314 | $47,534 | $42,863 | -$4,671 | -9.83% | |
| Citigroup Inc | 0.00% | 19,135 | $44,776 | $40,375 | -$4,401 | -9.83% | |
| Assenagon Asset Management S.A. | 0.00% | 18,636 | $43,608 | $39,322 | -$4,286 | -9.83% | |
| Occudo Quantitative Strategies Lp | 0.00% | 16,421 | $41,217 | $34,648 | -$6,569 | -15.94% | |
| Intrepid Family Office Llc | 0.03% | 16,279 | $38,093 | $34,349 | -$3,744 | -9.83% | |
| Torrey Growth & Income Advisors | 0.02% | 17,025 | $37,627 | $35,923 | -$1,704 | -4.53% | |
| Jones Financial Companies Lllp | 0.00% | 7,678 | $17,890 | $16,201 | -$1,689 | -9.44% | |
| Morgan Stanley | 0.00% | 4,552 | $10,651 | $9,605 | -$1,046 | -9.82% | |
| Ubs Group Ag | 0.00% | 3,009 | $7,041 | $6,349 | -$692 | -9.83% | |
| Osaic Holdings, Inc. | 0.00% | 290 | $678 | $612 | -$66 | -9.75% | |
| Gsa Capital Partners Llp | 0.04% | 278,304 | $651 | $587,221 | +$586,570 | +90102.99% | |
| Wells Fargo & Company/Mn | 0.00% | 200 | $468 | $422 | -$46 | -9.83% | |
| Us Bancorp \De\ | 0.00% | 151 | $353 | $319 | -$34 | -9.74% | |
| Bnp Paribas Financial Markets | 0.00% | 40 | $94 | $84 | -$10 | -10.21% | |
| Farther Finance Advisors, Llc | 0.00% | 10 | $25 | $21 | -$4 | -15.60% | |
| Sbi Securities Co., Ltd. | 0.00% | 9 | $21 | $19 | -$2 | -9.57% | |
| Fny Investment Advisers, Llc | 0.01% | 5,300 | $12 | $11,183 | +$11,171 | +93091.67% | |
| Caitong International Asset Management Co., Ltd | 0.00% | 3 | $7 | $6 | -$1 | -9.57% |
Frequently asked questions about SPRO
Who owns the most SPRO stock?
The largest holders of SPRO are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for SPERO THERAPEUTICS INC (SPRO).
Is SPRO widely held by superinvestors?
Many widely followed stocks like SPRO appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly SPRO is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.