Who owns Phathom Pharmaceuticals, Inc. (PHAT)
Which tracked institutional funds hold PHAT, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See PHAT company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
24 tracked funds added or opened PHAT while 62 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
PHAT’s largest tracked holder by dollar value, Frazier Life Sciences Management, L.P., sizes it at 3.6% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 3.6pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in PHAT divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 174 tracked filers holding PHAT, 112 increased or opened the position and 76 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in PHAT between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 15
- VANGUARD CAPITAL MANAGEMENT LLC$29M
- NOMURA ASSET MANAGEMENT INTERNATIONAL INC.$13M
- FRANKLIN RESOURCES INC$11M
- PERCEPTIVE ADVISORS LLC$10M
- MARSHALL WACE, LLP$10M
- VANGUARD PORTFOLIO MANAGEMENT LLC$7M
Full exits 8
- VANGUARD GROUP INC$47M
- Divisadero Street Capital Management, LP$11M
- MOORE CAPITAL MANAGEMENT, LP$10M
- NEXT CENTURY GROWTH INVESTORS LLC$7M
- JANE STREET GROUP, LLC$6M
- CAXTON ASSOCIATES LLP$3M
Largest adds
- MILLENNIUM MANAGEMENT LLC$10M
- TWO SIGMA INVESTMENTS, LP$4M
- SummitTX Capital, L.P.$2M
- XTX Topco Ltd$1M
- Woodline Partners LP$993K
- Trexquant Investment LP$989K
Largest trims
- Frazier Life Sciences Management, L.P.$68M
- Medicxi Ventures Management (Jersey) Ltd$41M
- Invesco Ltd.$21M
- Ensign Peak Advisors, Inc$21M
- Carlyle Group Inc.$19M
- BlackRock, Inc.$14M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| Frazier Life Sciences Management, L.P. | 12,466,489 | $139M | 15.4% | 2026-Q1 |
| Medicxi Ventures Management (Jersey) Ltd | 7,464,572 | $83M | 9.2% | 2026-Q1 |
| BlackRock, Inc. added | 4,061,996 | $45M | 5.0% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 4,022,909 | $45M | 5.0% | 2026-Q1 |
| Invesco Ltd. added | 3,945,322 | $44M | 4.9% | 2026-Q1 |
| Carlyle Group Inc. | 3,496,808 | $39M | 4.3% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 2,583,636 | $29M | 3.2% | 2026-Q1 |
| NEA Management Company, LLC | 1,960,169 | $22M | 2.4% | 2026-Q1 |
| 683 Capital Management, LLC added | 1,850,000 | $21M | 2.3% | 2026-Q1 |
| Ensign Peak Advisors, Inc trimmed | 1,627,806 | $18M | 2.0% | 2026-Q1 |
| Catalys Pacific, LLC added | 1,493,854 | $17M | 1.8% | 2026-Q1 |
| GW&K Investment Management, LLC added | 1,421,109 | $16M | 1.8% | 2026-Q1 |
| STATE STREET CORP added | 1,386,890 | $15M | 1.7% | 2026-Q1 |
| WASATCH ADVISORS LP added | 1,340,916 | $15M | 1.7% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,328,045 | $15M | 1.6% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. new | 1,205,369 | $13M | 1.5% | 2026-Q1 |
| SummitTX Capital, L.P. added | 995,885 | $11M | 1.2% | 2026-Q1 |
| FRANKLIN RESOURCES INC new | 994,504 | $11M | 1.2% | 2026-Q1 |
| PERCEPTIVE ADVISORS LLC new | 925,000 | $10M | 1.1% | 2026-Q1 |
| MARSHALL WACE, LLP added | 860,692 | $10M | 1.1% | 2026-Q1 |
| Propel Bio Management, LLC added | 841,272 | $9M | 1.0% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 666,029 | $7M | 0.8% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 626,196 | $7M | 0.8% | 2026-Q1 |
| EcoR1 Capital, LLC added | 625,000 | $7M | 0.8% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 482,136 | $5M | 0.6% | 2026-Q1 |
| StepStone Group LP | 422,085 | $5M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 414,956 | $5M | 0.5% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 409,015 | $5M | 0.5% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 383,058 | $4M | 0.5% | 2026-Q1 |
| Woodline Partners LP added | 369,052 | $4M | 0.5% | 2026-Q1 |
| UBS Group AG added | 360,371 | $4M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 338,713 | $4M | 0.4% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 305,800 | $3M | 0.4% | 2026-Q1 |
| Trexquant Investment LP added | 293,305 | $3M | 0.4% | 2026-Q1 |
| Squarepoint Ops LLC added | 275,161 | $3M | 0.3% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 287,430 | $3M | 0.3% | 2026-Q1 |
| Susquehanna Portfolio Strategies, LLC | 267,962 | $3M | 0.3% | 2026-Q1 |
| Simplify Asset Management Inc. trimmed | 262,386 | $3M | 0.3% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC added | 254,219 | $3M | 0.3% | 2026-Q1 |
| Avidity Partners Management LP added | 249,390 | $3M | 0.3% | 2026-Q1 |
| Catalio Capital Management, LP trimmed | 247,767 | $3M | 0.3% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ trimmed | 208,115 | $2M | 0.3% | 2026-Q1 |
| Birchview Capital, LP | 195,000 | $2M | 0.2% | 2026-Q1 |
| XTX Topco Ltd added | 160,501 | $2M | 0.2% | 2026-Q1 |
| Hennion & Walsh Asset Management, Inc. added | 145,932 | $2M | 0.2% | 2026-Q1 |
| GILDER GAGNON HOWE & CO LLC trimmed | 139,889 | $2M | 0.2% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 132,457 | $1M | 0.2% | 2026-Q1 |
| Bank of New York Mellon Corp added | 124,018 | $1M | 0.2% | 2026-Q1 |
| Nuveen, LLC added | 117,301 | $1M | 0.1% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 111,752 | $1M | 0.1% | 2026-Q1 |
| Stratos Wealth Partners, LTD. added | 100,000 | $1M | 0.1% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP added | 97,068 | $1M | 0.1% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 95,301 | $1M | 0.1% | 2026-Q1 |
| Brevan Howard Capital Management LP trimmed | 94,638 | $1M | 0.1% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 92,979 | $1M | 0.1% | 2026-Q1 |
| Swiss National Bank added | 92,600 | $1M | 0.1% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 85,683 | $952K | 0.1% | 2026-Q1 |
| Freestone Grove Partners LP new | 84,573 | $940K | 0.1% | 2026-Q1 |
| HUSSMAN STRATEGIC ADVISORS, INC. trimmed | 84,000 | $933K | 0.1% | 2026-Q1 |
| KBC Group NV new | 77,139 | $857K | 0.1% | 2026-Q1 |
| MORGAN STANLEY trimmed | 76,681 | $852K | 0.1% | 2026-Q1 |
| Burkehill Global Management, LP new | 75,000 | $833K | 0.1% | 2026-Q1 |
| Engineers Gate Manager LP added | 73,848 | $820K | 0.1% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. | 49,390 | $819K | 0.1% | 2026-Q1 |
| Creative Planning trimmed | 70,193 | $780K | 0.1% | 2026-Q1 |
| Penn Mutual Asset Management | 62,802 | $698K | 0.1% | 2026-Q1 |
| Campbell & CO Investment Adviser LLC trimmed | 62,023 | $689K | 0.1% | 2026-Q1 |
| Virtus Investment Advisers, LLC added | 57,986 | $644K | 0.1% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 55,788 | $620K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 55,439 | $616K | 0.1% | 2026-Q1 |
| DIADEMA PARTNERS LP added | 54,650 | $607K | 0.1% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 54,504 | $606K | 0.1% | 2026-Q1 |
| STIFEL FINANCIAL CORP added | 54,039 | $600K | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 52,453 | $583K | 0.1% | 2026-Q1 |
| Stonepine Capital Management, LLC new | 50,010 | $556K | 0.1% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 46,113 | $512K | 0.1% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 44,004 | $489K | 0.1% | 2026-Q1 |
| ADAR1 Capital Management, LLC | 42,900 | $477K | 0.1% | 2026-Q1 |
| Aquatic Capital Management LLC added | 40,852 | $454K | 0.1% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 40,222 | $447K | 0.0% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 39,420 | $438K | 0.0% | 2026-Q1 |
| VARCOV Co. trimmed | 39,173 | $435K | 0.0% | 2026-Q1 |
| TUDOR INVESTMENT CORP ET AL added | 38,225 | $425K | 0.0% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 2,812,646 | $47M | 5.2% | 2025-Q4 stale |
| JENNISON ASSOCIATES LLC trimmed | 7,042,325 | $44M | 4.9% | 2025-Q1 stale |
| Divisadero Street Capital Management, LP new | 662,312 | $11M | 1.2% | 2025-Q4 stale |
| MOORE CAPITAL MANAGEMENT, LP | 600,000 | $10M | 1.1% | 2025-Q4 stale |
| TANG CAPITAL MANAGEMENT LLC added | 1,200,000 | $8M | 0.8% | 2025-Q1 stale |
| NEXT CENTURY GROWTH INVESTORS LLC new | 393,774 | $7M | 0.7% | 2025-Q4 stale |
| JANE STREET GROUP, LLC added | 384,770 | $6M | 0.7% | 2025-Q4 stale |
| AIGH Capital Management LLC new | 429,000 | $5M | 0.6% | 2025-Q3 stale |
| JACOBS LEVY EQUITY MANAGEMENT, INC added | 596,108 | $4M | 0.4% | 2025-Q1 stale |
| PRUDENTIAL FINANCIAL INC added | 568,630 | $4M | 0.4% | 2025-Q1 stale |
| Walleye Capital LLC added | 290,467 | $3M | 0.4% | 2025-Q3 stale |
| CAXTON ASSOCIATES LLP added | 181,968 | $3M | 0.3% | 2025-Q4 stale |
| Southeast Asset Advisors, LLC new | 42,874 | $711K | 0.1% | 2025-Q4 stale |
| Y-Intercept (Hong Kong) Ltd new | 30,488 | $506K | 0.1% | 2025-Q4 stale |
| Occidental Asset Management, LLC added | 29,919 | $496K | 0.1% | 2025-Q4 stale |
| AlphaQuest LLC trimmed | 28,250 | $469K | 0.1% | 2025-Q4 stale |
| HRT FINANCIAL LP added | 27,010 | $448K | 0.0% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.