Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in SPRO held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | GSK plc | 9.2M | $21.5M | 0.0% | 15.873% | 3.59% |
| 2 | PFIZER INC | 2.4M | $5.5M | 0.0% | 4.080% | 2.31% |
| 3 | VANGUARD CAPITAL MANAGEMENT LLC | 1.8M | $4.2M | β | 3.109% | 0.00% |
| 4 | RENAISSANCE TECHNOLOGIES LLC | 1.2M | $2.8M | -7.1% | 2.054% | 0.00% |
| 5 | Alphabet Inc. | 890K | $2.1M | 0.0% | 1.537% | 0.05% |
| 6 | TWO SIGMA INVESTMENTS, LP | 886K | $2.1M | +137.7% | 1.529% | 0.00% |
| 7 | GEODE CAPITAL MANAGEMENT, LLC | 520K | $1.2M | -1.8% | 0.898% | 0.00% |
| 8 | BlackRock, Inc. | 433K | $1.0M | -0.1% | 0.748% | 0.00% |
| 9 | CITADEL ADVISORS LLC | 426K | $996K | -9.6% | 0.735% | 0.00% |
| 10 | Anson Funds Management LP | 422K | $987K | -32.5% | 0.729% | 0.13% |
| 11 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 382K | $893K | +29.9% | 0.659% | 0.00% |
| 12 | VANGUARD FIDUCIARY TRUST CO | 264K | $618K | β | 0.456% | 0.00% |
| 13 | STATE STREET CORP | 215K | $503K | +2.2% | 0.371% | 0.00% |
| 14 | Ionic Capital Management LLC | 196K | $458K | 0.0% | 0.338% | 0.44% |
| 15 | Squarepoint Ops LLC | 194K | $455K | +62.7% | 0.336% | 0.00% |
| 16 | MARSHALL WACE, LLP | 157K | $368K | β | 0.271% | 0.00% |
| 17 | NORTHERN TRUST CORP | 121K | $283K | 0.0% | 0.209% | 0.00% |
| 18 | BRIDGEWAY CAPITAL MANAGEMENT, LLC | 115K | $269K | 0.0% | 0.198% | 0.01% |
| 19 | Shay Capital LLC | 70K | $165K | +16.7% | 0.121% | 0.01% |
| 20 | Point72 Asset Management, L.P. | 60K | $140K | +36.9% | 0.103% | 0.00% |
| 21 | Invesco Ltd. | 45K | $106K | +83.7% | 0.078% | 0.00% |
| 22 | Quadrature Capital Ltd | 40K | $94K | +6.2% | 0.069% | 0.00% |
| 23 | Capital Asset Advisory Services LLC | 33K | $92K | 0.0% | 0.056% | 0.00% |
| 24 | OMERS ADMINISTRATION Corp | 39K | $92K | -70.0% | 0.068% | 0.00% |
| 25 | Verdad Advisers, LP | 33K | $78K | β | 0.058% | 0.09% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in SPRO β a direct measure of their conviction.
Filings activity in SPRO during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new SPRO position in Q1 2026
Institutions that fully closed their SPRO position in Q1 2026
8 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 48 | 14% | 28.85% | 0.87 pp | $48M | 2.9% |
| Q4 2025 | 56 | +22% | 29.72% | +16.97 pp | $49M | +133% |
| Q3 2025 | 46 | +4.5% | 12.75% | 6.79 pp | $21M | 35% |
| Q2 2025 | 44 | +13% | 19.54% | +10.96 pp | $32M | +128% |
| Q1 2025 | 39 | 22% | 8.58% | 0.41 pp | $14M | 4.5% |
| Q4 2024 | 50 | +11% | 8.99% | 0.07 pp | $15M | 0.9% |
| Q3 2024 | 45 | 6.3% | 9.06% | 0.77 pp | $15M | 7.8% |
| Q2 2024 | 48 | β | 9.83% | β | $16M | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying SPRO stock.
Based on Q1 2026 13F filings, institutional ownership of Spero Therapeutics, Inc. stands at 28.8%, held across 48 reporting institutions.
GSK plc is the largest reported institutional holder of SPRO, with approximately 9,190,606 shares worth $0.02B as of Q1 2026.
Yes β 5 widely-followed marquee investors appear among the top 25 institutional holders of SPRO, including RENAISSANCE TECHNOLOGIES LLC, TWO SIGMA INVESTMENTS, LP, CITADEL ADVISORS LLC, SUSQUEHANNA INTERNATIONAL GROUP, LLP, Point72 Asset Management, L.P..
Our composite Smart Money Score for SPRO is 53 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
8 institutions opened new positions in SPRO during Q1 2026, while 16 fully exited. 28 added to existing positions and 9 trimmed.
SPRO institutional ownership fell by 0.87 percentage points quarter-over-quarter, with a net change of -8 holders.
The top 10 institutions account for 89.0% of all reported 13F value in SPRO, and the top 25 account for 98.7%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Spero Therapeutics, Inc. (SPRO) Institutional Ownership