Who owns ASMB (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-Q1 13F filings. 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
12 tracked funds added or opened ASMB while 31 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
ASMB’s largest tracked holder by dollar value, GILEAD SCIENCES, INC., sizes it at 5.9% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 5.9pp 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 2025-Q4 and 2026-Q1, across 75 tracked filers holding ASMB, 47 increased or opened the position and 28 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
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 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 6
- VANGUARD CAPITAL MANAGEMENT LLC$14M
- HighVista Strategies LLC$2M
- VANGUARD FIDUCIARY TRUST CO$2M
- WELLINGTON MANAGEMENT GROUP LLP$735K
- Squarepoint Ops LLC$661K
- TWO SIGMA INVESTMENTS, LP$570K
Full exits 6
- VANGUARD GROUP INC$19M
- FRANKLIN RESOURCES INC$7M
- SUPERSTRING CAPITAL MANAGEMENT LP$2M
- Informed Momentum Co LLC$1M
- Ellsworth Advisors, LLC$889K
- SEI INVESTMENTS CO$604K
Largest adds
- MILLENNIUM MANAGEMENT LLC$3M
- Parkman Healthcare Partners LLC$3M
- Schonfeld Strategic Advisors LLC$1M
- Seven Fleet Capital Management LP$1M
- GSA CAPITAL PARTNERS LLP$818K
- Qube Research & Technologies Ltd$487K
Largest trims
- GILEAD SCIENCES, INC.$28M
- Point72 Asset Management, L.P.$11M
- FARALLON CAPITAL MANAGEMENT LLC$8M
- RA CAPITAL MANAGEMENT, L.P.$6M
- Commodore Capital LP$6M
- JANUS HENDERSON GROUP PLC$5M
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. | 4,505,391 | $125M | 29.5% | 2026-Q1 |
| FARALLON CAPITAL MANAGEMENT LLC | 1,227,590 | $34M | 8.0% | 2026-Q1 |
| RA CAPITAL MANAGEMENT, L.P. | 1,020,410 | $28M | 6.7% | 2026-Q1 |
| Commodore Capital LP | 1,000,000 | $28M | 6.5% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 849,309 | $23M | 5.5% | 2026-Q1 |
| Paradigm Biocapital Advisors LP | 665,251 | $18M | 4.4% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 490,447 | $14M | 3.2% | 2026-Q1 |
| Parkman Healthcare Partners LLC added | 411,227 | $11M | 2.7% | 2026-Q1 |
| Point72 Asset Management, L.P. trimmed | 344,105 | $10M | 2.3% | 2026-Q1 |
| Blackstone Inc. trimmed | 296,855 | $8M | 1.9% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 233,650 | $6M | 1.5% | 2026-Q1 |
| BlackRock, Inc. added | 202,743 | $6M | 1.3% | 2026-Q1 |
| STEMPOINT CAPITAL LP added | 185,435 | $5M | 1.2% | 2026-Q1 |
| B Group, Inc. | 175,706 | $5M | 1.1% | 2026-Q1 |
| MARSHALL WACE, LLP added | 163,400 | $5M | 1.1% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | 161,000 | $4M | 1.1% | 2026-Q1 |
| Patient Square Capital LP added | 136,315 | $4M | 0.9% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 132,971 | $4M | 0.9% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC added | 120,500 | $3M | 0.8% | 2026-Q1 |
| Caption Management, LLC trimmed | 81,841 | $2M | 0.5% | 2026-Q1 |
| HighVista Strategies LLC added | 74,735 | $2M | 0.5% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 71,606 | $2M | 0.5% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 69,256 | $2M | 0.5% | 2026-Q1 |
| STATE STREET CORP added | 56,689 | $2M | 0.4% | 2026-Q1 |
| Seven Fleet Capital Management LP added | 56,147 | $2M | 0.4% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 53,962 | $1M | 0.3% | 2026-Q1 |
| MONIMUS CAPITAL MANAGEMENT, LP added | 48,390 | $1M | 0.3% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP added | 45,049 | $1M | 0.3% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 41,014 | $1M | 0.3% | 2026-Q1 |
| Eversept Partners, LP trimmed | 40,889 | $1M | 0.3% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 39,446 | $1M | 0.3% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 36,205 | $1M | 0.2% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 34,499 | $957K | 0.2% | 2026-Q1 |
| MORGAN STANLEY added | 33,055 | $917K | 0.2% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 32,949 | $914K | 0.2% | 2026-Q1 |
| 683 Capital Management, LLC | 27,863 | $773K | 0.2% | 2026-Q1 |
| BARCLAYS PLC added | 27,050 | $751K | 0.2% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 26,496 | $735K | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 25,437 | $706K | 0.2% | 2026-Q1 |
| Squarepoint Ops LLC added | 23,804 | $661K | 0.2% | 2026-Q1 |
| Trexquant Investment LP trimmed | 22,741 | $631K | 0.1% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. added | 21,761 | $604K | 0.1% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 20,550 | $570K | 0.1% | 2026-Q1 |
| ADAR1 Capital Management, LLC added | 19,947 | $554K | 0.1% | 2026-Q1 |
| Palumbo Wealth Management LLC trimmed | 19,643 | $545K | 0.1% | 2026-Q1 |
| FEDERATED HERMES, INC. trimmed | 18,904 | $525K | 0.1% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 17,723 | $492K | 0.1% | 2026-Q1 |
| Hudson Bay Capital Management LP added | 16,799 | $466K | 0.1% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 15,651 | $434K | 0.1% | 2026-Q1 |
| Susquehanna Portfolio Strategies, LLC added | 14,100 | $391K | 0.1% | 2026-Q1 |
| EntryPoint Capital, LLC new | 12,384 | $344K | 0.1% | 2026-Q1 |
| Brevan Howard Capital Management LP new | 11,112 | $308K | 0.1% | 2026-Q1 |
| Jump Financial, LLC trimmed | 10,917 | $303K | 0.1% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 10,902 | $303K | 0.1% | 2026-Q1 |
| XTX Topco Ltd trimmed | 10,785 | $299K | 0.1% | 2026-Q1 |
| Engineers Gate Manager LP trimmed | 9,423 | $261K | 0.1% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 9,154 | $254K | 0.1% | 2026-Q1 |
| CANADA PENSION PLAN INVESTMENT BOARD added | 8,500 | $236K | 0.1% | 2026-Q1 |
| OMERS ADMINISTRATION Corp trimmed | 8,100 | $225K | 0.1% | 2026-Q1 |
| Virtus Investment Advisers, LLC added | 7,553 | $210K | 0.0% | 2026-Q1 |
| CITIGROUP INC added | 6,483 | $180K | 0.0% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 4,615 | $128K | 0.0% | 2026-Q1 |
| EverSource Wealth Advisors, LLC added | 200 | $23K | 0.0% | 2026-Q1 |
| Tower Research Capital LLC (TRC) trimmed | 544 | $15K | 0.0% | 2026-Q1 |
| UBS Group AG trimmed | 364 | $10K | 0.0% | 2026-Q1 |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO trimmed | 260 | $7K | 0.0% | 2026-Q1 |
| Aquatic Capital Management LLC new | 220 | $6K | 0.0% | 2026-Q1 |
| RHUMBLINE ADVISERS | 190 | $5K | 0.0% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 149 | $4K | 0.0% | 2026-Q1 |
| Accent Capital Management, LLC new | 142 | $4K | 0.0% | 2026-Q1 |
| OSAIC HOLDINGS, INC. | 100 | $3K | 0.0% | 2026-Q1 |
| US BANCORP \DE\ | 59 | $2K | 0.0% | 2026-Q1 |
| FIFTH THIRD BANCORP new | 57 | $2K | 0.0% | 2026-Q1 |
| Allworth Financial LP trimmed | 29 | $805 | 0.0% | 2026-Q1 |
| VANGUARD GROUP INC added | 572,898 | $19M | 4.6% | 2025-Q4 stale |
| Frazier Life Sciences Management, L.P. new | 456,249 | $12M | 2.8% | 2025-Q3 stale |
| FRANKLIN RESOURCES INC trimmed | 210,528 | $7M | 1.7% | 2025-Q4 stale |
| SUPERSTRING CAPITAL MANAGEMENT LP new | 65,273 | $2M | 0.5% | 2025-Q4 stale |
| MPM BIOIMPACT LLC new | 39,665 | $1M | 0.2% | 2025-Q3 stale |
| Informed Momentum Co LLC added | 29,523 | $1M | 0.2% | 2025-Q4 stale |
| Ellsworth Advisors, LLC trimmed | 29,735 | $889K | 0.2% | 2025-Q4 stale |
| Walleye Capital LLC trimmed | 24,501 | $627K | 0.1% | 2025-Q3 stale |
| SEI INVESTMENTS CO trimmed | 17,745 | $604K | 0.1% | 2025-Q4 stale |
| Quadrature Capital Ltd new | 17,935 | $459K | 0.1% | 2025-Q3 stale |
| RAYMOND JAMES FINANCIAL INC added | 13,082 | $445K | 0.1% | 2025-Q4 stale |
| ACADIAN ASSET MANAGEMENT LLC trimmed | 12,446 | $422K | 0.1% | 2025-Q4 stale |
| Cubist Systematic Strategies, LLC trimmed | 16,161 | $414K | 0.1% | 2025-Q3 stale |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 15,225 | $390K | 0.1% | 2025-Q3 stale |
| Man Group plc trimmed | 13,227 | $240K | 0.1% | 2025-Q2 stale |
| ARMISTICE CAPITAL, LLC trimmed | 23,858 | $228K | 0.1% | 2025-Q1 stale |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 6,704 | $228K | 0.1% | 2025-Q4 stale |
| Lynx1 Capital Management LP new | 10,366 | $188K | 0.0% | 2025-Q2 stale |
| FMR LLC trimmed | 5,659 | $54K | 0.0% | 2025-Q1 stale |
| Farther Finance Advisors, LLC new | 154 | $5K | 0.0% | 2025-Q4 stale |
| WELLS FARGO & COMPANY/MN | 145 | $4K | 0.0% | 2025-Q3 stale |
| SBI Securities Co., Ltd. added | 68 | $2K | 0.0% | 2025-Q3 stale |
| AMERIFLEX GROUP, INC. | 83 | $1K | 0.0% | 2025-Q2 stale |
| QUADRANT CAPITAL GROUP LLC | 22 | $749 | 0.0% | 2025-Q4 stale |
| Caitong International Asset Management Co., Ltd new | 34 | $616 | 0.0% | 2025-Q2 stale |
| Point72 Europe (London) LLP new | 13 | $332 | 0.0% | 2025-Q3 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.