SPERO THERAPEUTICS INC (SPRO) 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 June 30, 2026. The institutional investors covered on this page collectively reported approximately $47.43M 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 $20.31M in its June 30, 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 $10.39M, representing an estimated loss of -48.87% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 85% 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
58
Total Reported Value
$47.43M
Largest Holder
Gsk Plc
Largest Position
$20.31M
Insider Transactions (90d)
8
Latest Filing Quarter
Q2 2026
New Institutional Positions
79
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Gsk Plc | 3.37% | 9,190,606 | $20,311,239 | $10,385,385 | -$9,925,854 | -48.87% | |
| Pfizer Inc | 3.13% | 2,362,348 | $5,338,906 | $2,669,453 | -$2,669,453 | -50.00% | |
| Vanguard Capital Management Llc | 0.00% | 2,036,226 | $4,500,059 | $2,300,935 | -$2,199,124 | -48.87% | |
| Renaissance Technologies LLC | Jim Simons | 0.00% | 947,904 | $2,094,868 | $1,071,132 | -$1,023,736 | -48.87% |
| Alphabet Inc. | 0.00% | 889,979 | $1,966,854 | $1,005,676 | -$961,178 | -48.87% | |
| Susquehanna International Group, Llp | 0.00% | 759,290 | $1,678,031 | $857,998 | -$820,033 | -48.87% | |
| Blackrock, Inc. | 0.00% | 594,404 | $1,313,634 | $671,677 | -$641,957 | -48.87% | |
| Geode Capital Management, Llc | 0.00% | 566,329 | $1,252,145 | $639,952 | -$612,193 | -48.89% | |
| Raymond James Financial Inc | 0.00% | 521,705 | $1,152,968 | $589,527 | -$563,441 | -48.87% | |
| Two Sigma Investments, Lp | 0.00% | 382,814 | $846,019 | $432,580 | -$413,439 | -48.87% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 332,970 | $735,864 | $376,256 | -$359,608 | -48.87% | |
| Vanguard Fiduciary Trust Co | 0.00% | 287,648 | $635,702 | $325,042 | -$310,660 | -48.87% | |
| Gsa Capital Partners Llp | 0.04% | 285,906 | $632,000 | $323,074 | -$308,926 | -48.88% | |
| Dimensional Fund Advisors Lp | 0.00% | 274,820 | $607,616 | $310,547 | -$297,069 | -48.89% | |
| Goldman Sachs Group Inc | 0.00% | 256,985 | $567,937 | $290,393 | -$277,544 | -48.87% | |
| State Street Corp | 0.00% | 214,751 | $474,600 | $242,669 | -$231,931 | -48.87% | |
| Jane Street Group, Llc | 0.00% | 158,097 | $349,394 | $178,650 | -$170,744 | -48.87% | |
| Ubs Group Ag | 0.00% | 139,680 | $308,693 | $157,838 | -$150,855 | -48.87% | |
| Bridgeway Capital Management, Llc | 0.00% | 114,800 | $253,708 | $129,724 | -$123,984 | -48.87% | |
| Northern Trust Corp | 0.00% | 108,274 | $239,286 | $122,350 | -$116,936 | -48.87% | |
| Point72 Asset Management, L.P. | 0.00% | 104,377 | $230,673 | $117,946 | -$112,727 | -48.87% | |
| Ionic Capital Management Llc | 0.21% | 102,698 | $226,963 | $116,049 | -$110,914 | -48.87% | |
| Federation Des Caisses Desjardins Du Quebec | 0.00% | 91,900 | $202,180 | $103,847 | -$98,333 | -48.64% | |
| Shay Capital Llc | 0.02% | 72,391 | $159,984 | $81,802 | -$78,182 | -48.87% | |
| Invesco Ltd. | 0.00% | 64,245 | $141,981 | $72,597 | -$69,384 | -48.87% | |
| Simplex Trading, Llc | 0.00% | 61,312 | $135,499 | $69,283 | -$66,216 | -48.87% | |
| Verdad Advisers, Lp | 0.11% | 51,335 | $113,450 | $58,009 | -$55,441 | -48.87% | |
| Xtx Topco Ltd | 0.00% | 50,536 | $111,685 | $57,106 | -$54,579 | -48.87% | |
| American Century Companies Inc | 0.00% | 36,811 | $81,352 | $41,596 | -$39,756 | -48.87% | |
| Axxcess Wealth Management, Llc | 0.00% | 32,548 | $71,931 | $36,779 | -$35,152 | -48.87% | |
| Capital Asset Advisory Services Llc | 0.00% | 32,548 | $71,931 | $36,779 | -$35,152 | -48.87% | |
| Three Seasons Wealth, Llc | 0.01% | 30,000 | $66,300 | $33,900 | -$32,400 | -48.87% | |
| Charles Schwab Investment Management Inc | 0.00% | 28,565 | $63,129 | $32,278 | -$30,851 | -48.87% | |
| Vanguard Global Advisers, Llc | 0.00% | 25,446 | $56,236 | $28,754 | -$27,482 | -48.87% | |
| Oppenheimer & Co Inc | 0.00% | 22,850 | $50,499 | $25,820 | -$24,679 | -48.87% | |
| Millennium Management Llc | 0.00% | 19,298 | $42,649 | $21,807 | -$20,842 | -48.87% | |
| Assenagon Asset Management S.A. | 0.00% | 18,636 | $41,186 | $21,059 | -$20,127 | -48.87% | |
| Dlk Investment Management, Llc | 0.02% | 31,355 | $40,762 | $35,431 | -$5,331 | -13.08% | |
| Susquehanna Portfolio Strategies, Llc | 0.00% | 17,628 | $38,958 | $19,920 | -$19,038 | -48.87% | |
| Susquehanna Fundamental Investments, Llc | 0.00% | 16,095 | $35,570 | $18,187 | -$17,383 | -48.87% | |
| Qube Research & Technologies Ltd | 0.00% | 13,644 | $30,153 | $15,418 | -$14,735 | -48.87% | |
| Sg Americas Securities, Llc | 0.00% | 11,268 | $25,000 | $12,733 | -$12,267 | -49.07% | |
| Group One Trading Llc | 0.00% | 10,869 | $24,020 | $12,282 | -$11,738 | -48.87% | |
| Two Sigma Securities, Llc | 0.00% | 10,576 | $23,373 | $11,951 | -$11,422 | -48.87% | |
| Prudential Financial Inc | 0.00% | 10,400 | $22,984 | $11,752 | -$11,232 | -48.87% | |
| Citigroup Inc | 0.00% | 9,625 | $21,271 | $10,876 | -$10,395 | -48.87% | |
| Fny Investment Advisers, Llc | 0.01% | 8,300 | $18,000 | $9,379 | -$8,621 | -47.89% | |
| Jones Financial Companies Lllp | 0.00% | 7,678 | $17,352 | $8,676 | -$8,676 | -50.00% | |
| Royal Bank Of Canada | 0.00% | 2,014 | $4,000 | $2,276 | -$1,724 | -43.10% | |
| Morgan Stanley | 0.00% | 914 | $2,020 | $1,033 | -$987 | -48.87% |
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.