Assembly Biosciences, Inc. (ASMB) Ownership
ASMB ownership summary
as of October 17, 2026- Institutions
- 69.6% of shares outstanding
- Insiders
- 27.66% of shares outstanding
- Shares outstanding
- 20.4M
- Float
- 9.2M shares available to trade
- Short interest
- 18.45% 2.8M shares short
- Days to cover
- 7.57 short interest up 34.7% vs prior month
- Institutions 69.63%
- Insiders 27.66%
- Other investors 2.72%
ASMB top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Farallon Capital Management, L.L.C. | 8.08% | 1.6M | $32.2M | +377,000 (+30.7%) | June 30, 2026 |
| 2 | Paradigm Biocapital Advisors LP | 7.83% | 1.6M | $31.2M | +888,497 (+133.6%) | June 30, 2026 |
| 3 | COMMODORE CAPITAL LP | 7.13% | 1.4M | $28.4M | +415,000 (+41.5%) | June 30, 2026 |
| 4 | RA Capital Management, LLC | 5.14% | 1.0M | $20.5M | — | June 30, 2026 |
| 5 | HHG PLC | 4.28% | 849K | $17.1M | +11,384 (+1.4%) | March 31, 2026 |
| 6 | Jupiter Topco LLC | 4.28% | 849K | $17.1M | +849,309 (0.0%) | June 30, 2026 |
| 7 | BlackRock Inc | 3.86% | 767K | $15.4M | +564,076 (+278.2%) | June 30, 2026 |
| 8 | Parkman Healthcare Partners LLC | 3.63% | 721K | $14.5M | +309,954 (+75.4%) | June 30, 2026 |
| 9 | Vanguard Capital Management, LLC | 2.82% | 559K | $11.2M | +68,495 (+14.0%) | June 30, 2026 |
| 10 | Point72 Asset Management, L.P. | 2.32% | 461K | $9.3M | +116,488 (+33.9%) | June 30, 2026 |
| 11 | Seven Fleet Capital Management LP | 2.18% | 433K | $8.7M | +377,000 (+671.5%) | June 30, 2026 |
| 12 | Millennium Management LLC | 1.51% | 299K | $6.0M | +65,157 (+27.9%) | June 30, 2026 |
| 13 | Geode Capital Management, LLC | 1.41% | 280K | $5.6M | +147,453 (+110.9%) | June 30, 2026 |
| 14 | Schonfeld Strategic Advisors LLC | 1.22% | 242K | $4.9M | +121,653 (+101.0%) | June 30, 2026 |
| 15 | Ameriprise Financial Inc | 1.16% | 230K | $4.6M | +230,000 (0.0%) | June 30, 2026 |
| 16 | DV EQUITIES, LLC | 1.14% | 226K | $4.5M | +226,415 (0.0%) | June 30, 2026 |
| 17 | Aberdeen Group PLC | 1.04% | 207K | $4.2M | +207,047 (0.0%) | June 30, 2026 |
| 18 | Affinity Asset Advisors, LLC | 0.96% | 190K | $3.8M | +190,000 (0.0%) | June 30, 2026 |
| 19 | B Group, Inc | 0.89% | 176K | $3.5M | — | June 30, 2026 |
| 20 | State Street Corp | 0.87% | 172K | $3.5M | +115,242 (+203.3%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 18 holders added 5.3M shares and 0 cut 0.
ASMB top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 2.08% | 413K | $8.3M | — | August 31, 2026 |
| 2 | iShares Russell 2000 ETF | 1.72% | 341K | $6.8M | −3,904 (−1.1%) | September 30, 2026 |
| 3 | State Street® SPDR® S&P® Biotech ETF | 1.53% | 304K | $6.1M | −5,800 (−1.9%) | September 30, 2026 |
| 4 | iShares Russell 2000 Value ETF | 0.62% | 123K | $2.5M | +188 (+0.2%) | September 30, 2026 |
| 5 | Fidelity Small Cap Index | 0.54% | 107K | $2.2M | +683 (+0.6%) | July 31, 2026 |
| 6 | Franklin Biotechnology Discv A(acc)USD | 0.36% | 72K | $1.5M | — | August 31, 2026 |
| 7 | Fidelity Extended Market Index | 0.29% | 57K | $1.1M | +789 (+1.4%) | August 31, 2026 |
| 8 | Vanguard Russell 2000 ETF | 0.28% | 57K | $1.1M | +1,080 (+1.9%) | August 31, 2026 |
| 9 | iShares Micro-Cap ETF | 0.21% | 42K | $845,889 | −290 (−0.7%) | September 30, 2026 |
| 10 | Franklin Biotechnology Discovery A | 0.21% | 41K | $823,328 | — | August 31, 2026 |
| 11 | Vanguard Health Care ETF | 0.17% | 33K | $671,348 | +8,156 (+32.3%) | August 31, 2026 |
| 12 | Schwab Small Cap Index | 0.12% | 24K | $477,760 | — | August 31, 2026 |
| 13 | Fidelity Enhanced Small Cap Core ETF | 0.11% | 23K | $452,809 | +45 (+0.2%) | September 30, 2026 |
| 14 | Fidelity Total Market Index | 0.11% | 21K | $426,611 | — | August 31, 2026 |
| 15 | Northern Small Cap Value | 0.10% | 21K | $416,426 | +20,728 (0.0%) | June 30, 2026 |
| 16 | BlackRock Advantage Small Cap Core Instl | 0.10% | 19K | $379,661 | +18,898 (0.0%) | August 31, 2026 |
| 17 | MFS Blended Research Small Cap Eq R6 | 0.09% | 19K | $377,652 | +3,525 (+23.1%) | August 31, 2026 |
| 18 | iShares Russell 2000 Small-Cap Idx Instl | 0.09% | 18K | $370,158 | — | August 31, 2026 |
| 19 | Fidelity Series Total Market Index | 0.09% | 18K | $362,002 | — | August 31, 2026 |
| 20 | Avantis US Small Cap Equity ETF | 0.08% | 17K | $334,880 | +68 (+0.4%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ASMB insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2025-03-31 | Jeanette M Bjorkquist | Sell | $9.85 | 180 | $1,773 |
| 2025-03-31 | John G Mchutchison | Sell | $9.85 | 757 | $7,456 |
| 2025-03-31 | Jason A Okazaki | Sell | $9.85 | 355 | $3,497 |
| 2024-12-30 | Michael Houghton | Buy | $15.61 | 3,202 | $49,983 |
| 2024-11-18 | Nicole S White | Sell | $16.29 | 40 | $652 |
| 2024-10-08 | Alexander Schornstein | Buy | $14.58 | 10,000 | $145,800 |
| 2024-10-03 | Jason A Okazaki | Sell | $14.81 | 197 | $2,918 |
| 2024-10-03 | Nicole S White | Sell | $14.81 | 157 | $2,325 |
| 2024-07-05 | Alexander Schornstein | Buy | $12.52 | 4,438 | $55,564 |
| 2024-07-03 | Alexander Schornstein | Buy | $12.29 | 4,562 | $56,067 |
| 2024-05-23 | Jason A Okazaki | Sell | $14.93 | 549 | $8,197 |
| 2024-05-23 | Jeanette M Bjorkquist | Sell | $14.93 | 24 | $358 |
| 2024-05-23 | John G Mchutchison | Sell | $14.93 | 2,117 | $31,607 |
| 2024-04-30 | Jason A Okazaki | Sell | $12.71 | 1,569 | $19,942 |
| 2024-04-30 | Nicole S White | Sell | $12.71 | 1,255 | $15,951 |
| 2024-04-01 | Jason A Okazaki | Sell | $13.07 | 354 | $4,627 |
| 2024-04-01 | Jeanette M Bjorkquist | Sell | $13.07 | 114 | $1,490 |
| 2024-04-01 | John G Mchutchison | Sell | $13.07 | 1,206 | $15,762 |
| 2024-03-27 | Jason A Okazaki | Sell | $12.87 | 392 | $5,045 |
| 2024-01-17 | Alexander Schornstein | Buy | $9.36 | 24,999 | $233,991 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ASMB shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ASMB
Institutional investors own 69.6% of Assembly Biosciences's shares and insiders 27.66%. The largest holder is Farallon Capital Management, L.L.C. with 8.08% of the shares (1.6M), as of June 30, 2026. Among the top 20 institutions, 18 added shares and 0 reduced their stake in the latest filings. Short interest is 18.45% of the float, or 7.57 days of average trading volume. The share count rose 903.0% since 2014.
Related: ASMB analyst forecast, ASMB key metrics. See the ASMB stock overview for the latest quote and news.
ASMB ownership FAQ
Who owns the most Assembly Biosciences stock?
The largest shareholders of Assembly Biosciences are Farallon Capital Management, L.L.C. (8.08%), Paradigm Biocapital Advisors LP (7.83%), COMMODORE CAPITAL LP (7.13%), RA Capital Management, LLC (5.14%), HHG PLC (4.28%).
What percentage of Assembly Biosciences is owned by institutions?
Institutions hold 69.6% of Assembly Biosciences's shares outstanding; insiders hold 27.66%.
Which funds own Assembly Biosciences?
The largest fund holders of Assembly Biosciences are Vanguard MStar Total Stk Mkt Idx Invest (2.08%), iShares Russell 2000 ETF (1.72%), State Street® SPDR® S&P® Biotech ETF (1.53%), iShares Russell 2000 Value ETF (0.62%), Fidelity Small Cap Index (0.54%).
What is Assembly Biosciences's short interest?
2.8M shares of Assembly Biosciences were sold short, 18.45% of the float; at the average daily volume it would take 7.57 days to cover.
Are insiders buying or selling Assembly Biosciences?
Of the latest 20 reported insider transactions in Assembly Biosciences (since January 17, 2024), 5 were purchases and 15 were sales.
How many shares of Assembly Biosciences are outstanding?
Assembly Biosciences has 20.4M shares outstanding, of which 9.2M are in the public float.