Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in PHAT held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | Frazier Life Sciences Management, L.P. | 12.5M | $138.5M | 0.0% | 15.695% | 3.56% |
| 2 | Medicxi Ventures Management (Jersey) Ltd | 7.5M | $82.9M | 0.0% | 9.398% | 8.45% |
| 3 | Invesco Ltd. | 4.3M | $48.0M | +10.2% | 5.441% | 0.01% |
| 4 | BlackRock, Inc. | 4.1M | $45.1M | +14.2% | 5.114% | 0.00% |
| 5 | MILLENNIUM MANAGEMENT LLC | 4.0M | $44.7M | +93.2% | 5.065% | 0.03% |
| 6 | Carlyle Group Inc. | 3.5M | $38.8M | 0.0% | 4.402% | 0.37% |
| 7 | VANGUARD CAPITAL MANAGEMENT LLC | 2.6M | $28.7M | β | 3.253% | 0.00% |
| 8 | NEA Management Company, LLC | 2.0M | $21.8M | 0.0% | 2.468% | 1.24% |
| 9 | 683 Capital Management, LLC | 1.9M | $20.6M | +3.6% | 2.329% | 1.59% |
| 10 | Ensign Peak Advisors, Inc | 1.6M | $18.1M | -30.8% | 2.049% | 0.03% |
| 11 | Catalys Pacific, LLC | 1.5M | $16.6M | +4.5% | 1.881% | 7.19% |
| 12 | STATE STREET CORP | 1.4M | $15.4M | +20.6% | 1.746% | 0.00% |
| 13 | WASATCH ADVISORS INC | 1.3M | $14.9M | +0.7% | 1.688% | 0.10% |
| 14 | GEODE CAPITAL MANAGEMENT, LLC | 1.3M | $14.8M | +23.7% | 1.672% | 0.00% |
| 15 | NOMURA ASSET MANAGEMENT INTERNATIONAL INC. | 1.2M | $13.4M | β | 1.517% | 0.02% |
| 16 | SummitTX Capital, L.P. | 996K | $11.1M | +92.3% | 1.254% | 0.35% |
| 17 | FRANKLIN RESOURCES INC | 995K | $11.0M | β | 1.252% | 0.00% |
| 18 | PERCEPTIVE ADVISORS LLC | 925K | $10.3M | β | 1.165% | 0.20% |
| 19 | CITADEL ADVISORS LLC | 918K | $10.2M | +123.8% | 1.156% | 0.00% |
| 20 | MARSHALL WACE, LLP | 861K | $9.6M | β | 1.084% | 0.01% |
| 21 | Propel Bio Management, LLC | 841K | $9.4M | +13.5% | 1.059% | 5.90% |
| 22 | VANGUARD PORTFOLIO MANAGEMENT LLC | 666K | $7.4M | β | 0.839% | 0.00% |
| 23 | GOLDMAN SACHS GROUP INC | 626K | $7.0M | +59.7% | 0.788% | 0.00% |
| 24 | EcoR1 Capital, LLC | 625K | $6.9M | β | 0.787% | 0.29% |
| 25 | TWO SIGMA INVESTMENTS, LP | 482K | $5.4M | +734.4% | 0.607% | 0.00% |
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 PHAT β a direct measure of their conviction.
Filings activity in PHAT during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new PHAT position in Q1 2026
Institutions that fully closed their PHAT 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 | 170 | 0.6% | 91.03% | 30.29 pp | $750M | 25% |
| Q4 2025 | 171 | +31% | 121.32% | +34.01 pp | $999M | +39% |
| Q3 2025 | 131 | +11% | 87.31% | +20.80 pp | $719M | +31% |
| Q2 2025 | 118 | 13% | 66.51% | +18.93 pp | $548M | +40% |
| Q1 2025 | 136 | 6.2% | 47.58% | 19.28 pp | $392M | 29% |
| Q4 2024 | 145 | +9.0% | 66.86% | 89.05 pp | $551M | 57% |
| Q3 2024 | 133 | +17% | 155.91% | +85.56 pp | $1.28B | +122% |
| Q2 2024 | 114 | β | 70.35% | β | $579M | 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 PHAT stock.
Based on Q1 2026 13F filings, institutional ownership of Phathom Pharmaceuticals, Inc. stands at 91.0%, held across 170 reporting institutions.
Frazier Life Sciences Management, L.P. is the largest reported institutional holder of PHAT, with approximately 12,466,489 shares worth $0.14B as of Q1 2026.
Yes β 3 widely-followed marquee investors appear among the top 25 institutional holders of PHAT, including MILLENNIUM MANAGEMENT LLC, CITADEL ADVISORS LLC, TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for PHAT is 47 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
36 institutions opened new positions in PHAT during Q1 2026, while 37 fully exited. 24 added to existing positions and 108 trimmed.
PHAT institutional ownership fell by 30.29 percentage points quarter-over-quarter, with a net change of -1 holders.
The top 10 institutions account for 65.0% of all reported 13F value in PHAT, and the top 25 account for 86.8%.
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.
Phathom Pharmaceuticals, Inc. (PHAT) Institutional Ownership