Who owns Assembly Biosciences (ASMB)
Which tracked institutional funds hold ASMB, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ASMB company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 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
37 tracked funds added or opened ASMB while 18 trimmed or exited it between 2026-Q1 and 2026-Q2 — 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
ASMB’s largest tracked holder by dollar value, GILEAD SCIENCES, INC., sizes it at 8.3% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 8.3pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in ASMB 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 2026-Q1 and 2026-Q2, across 92 tracked filers holding ASMB, 69 increased or opened the position and 33 reduced or closed it; over the same quarter, open-market insider Form 4s were net sales.
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 ASMB between the 2026-Q1 and 2026-Q2 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 12
- Jupiter Topco LLC$23M
- AMERIPRISE FINANCIAL INC$6M
- DV EQUITIES, LLC$6M
- Aberdeen Group plc$6M
- Affinity Asset Advisors, LLC$5M
- Squadron Capital Management LLC$4M
Full exits 11
- JANUS HENDERSON GROUP PLC$23M
- Blackstone Inc.$8M
- ADAGE CAPITAL PARTNERS GP, L.L.C.$4M
- Patient Square Capital LP$4M
- GSA CAPITAL PARTNERS LLP$1M
- ARROWSTREET CAPITAL, LIMITED PARTNERSHIP$1M
Largest adds
- Paradigm Biocapital Advisors LP$24M
- BlackRock, Inc.$15M
- GILEAD SCIENCES, INC.$12M
- Commodore Capital LP$11M
- Seven Fleet Capital Management LP$10M
- FARALLON CAPITAL MANAGEMENT, L.L.C.$10M
Largest trims
- MARSHALL WACE, LLP$4M
- Caption Management, LLC$2M
- Eversept Partners, LP$681K
- BARCLAYS PLC$582K
- Qube Research & Technologies Ltd$507K
- STEMPOINT CAPITAL LP$464K
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 |
|---|---|---|---|---|
| GILEAD SCIENCES, INC. added | 4,977,089 | $137M | 23.3% | 2026-Q2 |
| FARALLON CAPITAL MANAGEMENT, L.L.C. added | 1,604,590 | $44M | 7.5% | 2026-Q2 |
| Paradigm Biocapital Advisors LP added | 1,553,748 | $43M | 7.3% | 2026-Q2 |
| Commodore Capital LP added | 1,415,000 | $39M | 6.6% | 2026-Q2 |
| RA CAPITAL MANAGEMENT, L.P. | 1,020,410 | $28M | 4.8% | 2026-Q2 |
| Jupiter Topco LLC new | 849,309 | $23M | 4.0% | 2026-Q2 |
| BlackRock, Inc. added | 766,819 | $21M | 3.6% | 2026-Q2 |
| Parkman Healthcare Partners LLC added | 721,181 | $20M | 3.4% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 558,942 | $15M | 2.6% | 2026-Q2 |
| Point72 Asset Management, L.P. added | 460,593 | $13M | 2.2% | 2026-Q2 |
| Seven Fleet Capital Management LP added | 433,147 | $12M | 2.0% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC added | 298,807 | $8M | 1.4% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 280,424 | $8M | 1.3% | 2026-Q2 |
| Schonfeld Strategic Advisors LLC added | 242,153 | $7M | 1.1% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC new | 230,000 | $6M | 1.1% | 2026-Q2 |
| DV EQUITIES, LLC new | 226,415 | $6M | 1.1% | 2026-Q2 |
| Aberdeen Group plc new | 207,047 | $6M | 1.0% | 2026-Q2 |
| Affinity Asset Advisors, LLC new | 190,000 | $5M | 0.9% | 2026-Q2 |
| B Group, Inc. | 175,706 | $5M | 0.8% | 2026-Q2 |
| STATE STREET CORP added | 171,931 | $5M | 0.8% | 2026-Q2 |
| STEMPOINT CAPITAL LP trimmed | 170,378 | $5M | 0.8% | 2026-Q2 |
| Squadron Capital Management LLC new | 160,000 | $4M | 0.7% | 2026-Q2 |
| Woodline Partners LP new | 150,780 | $4M | 0.7% | 2026-Q2 |
| Driehaus Capital Management LLC new | 150,000 | $4M | 0.7% | 2026-Q2 |
| Ally Bridge Group (NY) LLC new | 140,000 | $4M | 0.7% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 137,833 | $4M | 0.6% | 2026-Q2 |
| NORTHERN TRUST CORP added | 123,029 | $3M | 0.6% | 2026-Q2 |
| FRANKLIN RESOURCES INC trimmed | 113,200 | $3M | 0.5% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 95,907 | $3M | 0.4% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC added | 91,153 | $3M | 0.4% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 73,970 | $2M | 0.3% | 2026-Q2 |
| HighVista Strategies LLC trimmed | 73,405 | $2M | 0.3% | 2026-Q2 |
| Qube Research & Technologies Ltd trimmed | 51,488 | $1M | 0.2% | 2026-Q2 |
| MONIMUS CAPITAL MANAGEMENT, LP trimmed | 47,580 | $1M | 0.2% | 2026-Q2 |
| Trexquant Investment LP added | 45,661 | $1M | 0.2% | 2026-Q2 |
| JPMORGAN CHASE & CO trimmed | 46,385 | $1M | 0.2% | 2026-Q2 |
| MORGAN STANLEY added | 45,219 | $1M | 0.2% | 2026-Q2 |
| XTX Topco Ltd added | 42,918 | $1M | 0.2% | 2026-Q2 |
| UBS Group AG added | 41,806 | $1M | 0.2% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC added | 39,441 | $1M | 0.2% | 2026-Q2 |
| Squarepoint Ops LLC added | 34,214 | $940K | 0.2% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 29,128 | $800K | 0.1% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 24,203 | $665K | 0.1% | 2026-Q2 |
| Bank of New York Mellon Corp new | 24,015 | $660K | 0.1% | 2026-Q2 |
| Connor, Clark & Lunn Investment Management Ltd. added | 23,765 | $653K | 0.1% | 2026-Q2 |
| Caption Management, LLC trimmed | 22,829 | $627K | 0.1% | 2026-Q2 |
| ADAR1 Capital Management, LLC added | 20,447 | $562K | 0.1% | 2026-Q2 |
| Palumbo Wealth Management LLC added | 19,865 | $546K | 0.1% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP trimmed | 17,858 | $491K | 0.1% | 2026-Q2 |
| Engineers Gate Manager LP added | 17,766 | $488K | 0.1% | 2026-Q2 |
| MARSHALL WACE, LLP trimmed | 17,735 | $487K | 0.1% | 2026-Q2 |
| Nuveen, LLC new | 16,875 | $464K | 0.1% | 2026-Q2 |
| Eversept Partners, LP trimmed | 16,510 | $454K | 0.1% | 2026-Q2 |
| Susquehanna Portfolio Strategies, LLC added | 15,129 | $416K | 0.1% | 2026-Q2 |
| Virtus Investment Advisers, LLC added | 14,251 | $392K | 0.1% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC added | 13,239 | $364K | 0.1% | 2026-Q2 |
| Invesco Ltd. new | 11,864 | $326K | 0.1% | 2026-Q2 |
| RHUMBLINE ADVISERS added | 11,590 | $318K | 0.1% | 2026-Q2 |
| Integrated Quantitative Investments LLC new | 10,078 | $277K | 0.0% | 2026-Q2 |
| DEUTSCHE BANK AG\ new | 9,615 | $264K | 0.0% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ trimmed | 9,567 | $263K | 0.0% | 2026-Q2 |
| CANADA PENSION PLAN INVESTMENT BOARD | 8,500 | $234K | 0.0% | 2026-Q2 |
| EntryPoint Capital, LLC trimmed | 8,285 | $228K | 0.0% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 8,253 | $227K | 0.0% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ new | 8,203 | $226K | 0.0% | 2026-Q2 |
| Brevan Howard Capital Management LP trimmed | 7,765 | $213K | 0.0% | 2026-Q2 |
| Persistent Asset Partners Ltd new | 6,942 | $191K | 0.0% | 2026-Q2 |
| BARCLAYS PLC trimmed | 6,133 | $169K | 0.0% | 2026-Q2 |
| MetLife Investment Management, LLC new | 5,885 | $162K | 0.0% | 2026-Q2 |
| Vanguard Global Advisers, LLC | 4,615 | $127K | 0.0% | 2026-Q2 |
| CITIGROUP INC trimmed | 4,554 | $125K | 0.0% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. new | 4,519 | $124K | 0.0% | 2026-Q2 |
| NEW YORK STATE COMMON RETIREMENT FUND new | 4,200 | $115K | 0.0% | 2026-Q2 |
| Police & Firemen's Retirement System of New Jersey new | 2,907 | $80K | 0.0% | 2026-Q2 |
| Legal & General Group Plc new | 958 | $26K | 0.0% | 2026-Q2 |
| Ameritas Investment Partners, Inc. new | 895 | $25K | 0.0% | 2026-Q2 |
| Russell Investments Group, Ltd. new | 788 | $22K | 0.0% | 2026-Q2 |
| HSBC HOLDINGS PLC new | 16,935 | $17K | 0.0% | 2026-Q2 |
| Tower Research Capital LLC (TRC) trimmed | 530 | $15K | 0.0% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 440 | $12K | 0.0% | 2026-Q2 |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO | 260 | $7K | 0.0% | 2026-Q2 |
| Accent Capital Management, LLC added | 212 | $6K | 0.0% | 2026-Q2 |
| Sterling Capital Management LLC new | 199 | $5K | 0.0% | 2026-Q2 |
| Truvestments Capital LLC new | 193 | $5K | 0.0% | 2026-Q2 |
| FMR LLC trimmed | 178 | $5K | 0.0% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM new | 136 | $4K | 0.0% | 2026-Q2 |
| Integrated Wealth Concepts LLC new | 108 | $3K | 0.0% | 2026-Q2 |
| OSAIC HOLDINGS, INC. | 100 | $3K | 0.0% | 2026-Q2 |
| Quarry LP new | 75 | $2K | 0.0% | 2026-Q2 |
| Caitong International Asset Management Co., Ltd added | 75 | $2K | 0.0% | 2026-Q2 |
| EverSource Wealth Advisors, LLC trimmed | 55 | $2K | 0.0% | 2026-Q2 |
| Allworth Financial LP trimmed | 10 | $275 | 0.0% | 2026-Q2 |
| JANUS HENDERSON GROUP PLC added | 849,309 | $23M | 4.0% | 2026-Q1 stale (1 quarter behind) |
| Blackstone Inc. trimmed | 296,855 | $8M | 1.4% | 2026-Q1 stale (1 quarter behind) |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | 161,000 | $4M | 0.8% | 2026-Q1 stale (1 quarter behind) |
| Patient Square Capital LP added | 136,315 | $4M | 0.6% | 2026-Q1 stale (1 quarter behind) |
| GSA CAPITAL PARTNERS LLP added | 45,049 | $1M | 0.2% | 2026-Q1 stale (1 quarter behind) |
| VANGUARD GROUP INC added | 572,898 | $19M | 3.3% | 2025-Q4 stale (2 quarters behind) |
| SUPERSTRING CAPITAL MANAGEMENT LP new | 65,273 | $2M | 0.4% | 2025-Q4 stale (2 quarters behind) |
| Frazier Life Sciences Management, L.P. new | 456,249 | $12M | 2.0% | 2025-Q3 stale (3 quarters behind) |
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.