ASSEMBLY BIOSCIENCES INC ASMB
COM NEW · Common Stock · CUSIP 045396207
Company in Carmel, United States
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersSouth San Francisco, CA
- Founded2014
- Websiteassemblybio.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 15.9m as of 2026-03-13, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $27.74. Options: 1 managers hold calls ($5.5k notional), 0 hold puts (—).
Trends to Q1 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q1 2024 | 25 |
| Q2 2024 | 28 |
| Q3 2024 | 31 |
| Q4 2024 | 36 |
| Q1 2025 | 38 |
| Q2 2025 | 34 |
| Q3 2025 | 57 |
| Q4 2025 | 69 |
| Q1 2026 | 75 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q2 2024 | 14 | 8 |
| Q3 2024 | 12 | 8 |
| Q4 2024 | 16 | 12 |
| Q1 2025 | 17 | 14 |
| Q2 2025 | 12 | 17 |
| Q3 2025 | 46 | 10 |
| Q4 2025 | 44 | 21 |
| Q1 2026 | 41 | 27 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q2 2025 | $0 | $0 | — |
| Q3 2025 | $11.4m | $0 | 0.00 |
| Q4 2025 | $85.0k | $6.8k | 0.08 |
| Q1 2026 | $5.5k | $0 | 0.00 |
Biggest buyers
| STEMPOINT CAPITAL LP | Added | +214.1k |
| Parkman Healthcare Partners LLC | Added | +161.9k |
| MILLENNIUM MANAGEMENT LLC | Added | +135.4k |
| HighVista Strategies LLC | New | +74.7k |
| Schonfeld Strategic Advisors LLC | Added | +66.3k |
| MARSHALL WACE, LLP | Added | +34.3k |
| GSA CAPITAL PARTNERS LLP | Added | +32.4k |
| Qube Research & Technologies Ltd | Added | +27.1k |
| WELLINGTON MANAGEMENT GROUP LLP | New | +26.5k |
| Squarepoint Ops LLC | New | +23.8k |
Biggest sellers
| Point72 Asset Management, L.P. | Reduced | -256.5k |
| FRANKLIN RESOURCES INC | Sold out | -210.5k |
| Eversept Partners, LP | Reduced | -118.8k |
| SUPERSTRING CAPITAL MANAGEMENT LP | Sold out | -65.3k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | -47.4k |
| Ellsworth Advisors, LLC | Sold out | -29.7k |
| Informed Momentum Co LLC | Sold out | -29.5k |
| Caption Management, LLC | Reduced | -24.8k |
| Blackstone Inc. | Reduced | -21.9k |
| JANE STREET GROUP, LLC | Reduced | -19.2k |
Biggest calls
| SIMPLEX TRADING, LLC | Reduced | $5.5k200 shares |
Biggest puts
| None |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| ARMISTICE CAPITAL, LLC 13G · institution filed 2025-08-14 | 10.0% |
| Commodore Capital LP 13G · passive investor new · filed 2025-08-15 | 9.9% |
| RA CAPITAL MANAGEMENT, L.P. 13G · passive investor new · filed 2025-08-18 | 9.5% |
| FARALLON CAPITAL MANAGEMENT, L.L.C. 13G · institution filed 2026-08-04 | 8.1% |
| Paradigm Biocapital Advisors LP 13G · passive investor +2.4 pts · filed 2026-08-14 | 7.8% |
| Farallon Capital Partners, L.P. 13G · passive investor +0.5 pts · filed 2026-02-09 | 7.8% |
| Janus Henderson Group Ltd. 13G · institution -1.3 pts · filed 2026-08-13 | 6.9% |
Insider purchases and sales in Q1 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q2 2024 | 0 | — | 4 | $103.1k | — |
| Q3 2024 | 0 | — | 2 | $25.1k | — |
| Q4 2024 | 1 | $50.0k | 2 | $5.9k | — |
| Q1 2025 | 0 | — | 4 | $14.7k | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 0 | — | — |
| Q1 2026 | 0 | — | 2 | $14.0k | — |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-03-30 | Bjorkquist Jeanette M PFO and PAO | Sold | $8.8k328 shares |
| 2026-03-30 | White Nicole S Chief Manufacturing Officer | Sold | $5.3k197 shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q1 2026
| Manager | Shares | Change |
|---|---|---|
| GILEAD SCIENCES, INC. 5.90% of their portfolio | 4.5m $125.0m | Unchanged |
| FARALLON CAPITAL MANAGEMENT, L.L.C. 0.20% of their portfolio | 1.2m $34.1m | Unchanged |
| RA CAPITAL MANAGEMENT, L.P. 0.30% of their portfolio | 1.0m $28.3m | Unchanged |
| Commodore Capital LP 1.61% of their portfolio | 1.0m $27.8m | Unchanged |
| JANUS HENDERSON GROUP PLC 0.01% of their portfolio | 849.3k $23.5m | Added +11.4k |
| Paradigm Biocapital Advisors LP 0.38% of their portfolio | 665.3k $18.5m | Unchanged |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 490.4k $13.6m | First filing |
| Parkman Healthcare Partners LLC 1.18% of their portfolio | 411.2k $11.4m | Added +161.9k |
| STEMPOINT CAPITAL LP 1.00% of their portfolio | 370.9k $10.3m | Added +214.1k |
| Point72 Asset Management, L.P. 0.02% of their portfolio | 344.1k $9.5m | Reduced -256.5k |
| Blackstone Inc. 0.03% of their portfolio | 296.9k $8.2m | Reduced -21.9k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 233.7k $6.5m | Added +135.4k |
| BlackRock, Inc. 0.00% of their portfolio | 202.7k $5.6m | Added +10.4k |
| B Group, Inc. 3.61% of their portfolio | 175.7k $4.9m | Unchanged |
| MARSHALL WACE, LLP 0.00% of their portfolio | 163.4k $4.5m | Added +34.3k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.01% of their portfolio | 161.0k $4.5m | Unchanged |
| Patient Square Capital LP 0.67% of their portfolio | 136.3k $3.8m | Added +9.3k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 133.0k $3.7m | Added +1.7k |
| Schonfeld Strategic Advisors LLC 0.03% of their portfolio | 120.5k $3.3m | Added +66.3k |
| Caption Management, LLC 0.11% of their portfolio | 81.8k $2.3m | Reduced -24.8k |
| HighVista Strategies LLC 0.57% of their portfolio | 74.7k $2.1m | New |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 71.6k $2.0m | First filing |
| Qube Research & Technologies Ltd 0.00% of their portfolio | 69.3k $1.9m | Added +27.1k |
| STATE STREET CORP 0.00% of their portfolio | 56.7k $1.6m | Added +3.7k |
| Seven Fleet Capital Management LP 0.49% of their portfolio | 56.1k $1.6m | Reduced -17.6k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 54.0k $1.4m | Added +5.8k |
| MONIMUS CAPITAL MANAGEMENT, LP 0.37% of their portfolio | 48.4k $1.3m | Added +10.1k |
| GSA CAPITAL PARTNERS LLP 0.08% of their portfolio | 45.0k $1.2m | Added +32.4k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 41.0k $1.1m | Reduced -213 |
| Eversept Partners, LP 0.07% of their portfolio | 40.9k $1.1m | Reduced -118.8k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 39.4k $1.1m | Added +1.6k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 36.2k $1.0m | Added +1.4k |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 34.5k $957.3k | Reduced -19.2k |
| MORGAN STANLEY 0.00% of their portfolio | 33.1k $917.3k | Added +10.5k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 32.9k $914.3k | Reduced -47.4k |
| 683 Capital Management, LLC 0.07% of their portfolio | 27.9k $773.2k | Unchanged |
| BARCLAYS PLC 0.00% of their portfolio | 27.1k $750.6k | Added +2.3k |
| WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio | 26.5k $735.3k | New |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 25.4k $705.9k | Reduced -7.4k |
| Squarepoint Ops LLC 0.00% of their portfolio | 23.8k $660.6k | New |
| Trexquant Investment LP 0.00% of their portfolio | 22.7k $631.1k | Reduced -5.5k |
| Connor, Clark & Lunn Investment Management Ltd. 0.00% of their portfolio | 21.8k $603.9k | Added +959 |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 20.6k $570.3k | New |
| ADAR1 Capital Management, LLC 0.03% of their portfolio | 19.9k $553.5k | Added +200 |
| Palumbo Wealth Management LLC 0.13% of their portfolio | 19.6k $545.1k | Reduced -17.7k |
| FEDERATED HERMES, INC. 0.00% of their portfolio | 18.9k $524.6k | Reduced -6.5k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 17.7k $491.8k | First filing |
| Hudson Bay Capital Management LP 0.00% of their portfolio | 16.8k $466.2k | Added +1.7k |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 15.7k $434.3k | Added +6.4k |
| Susquehanna Portfolio Strategies, LLC 0.01% of their portfolio | 14.1k $391.3k | Added +197 |
| EntryPoint Capital, LLC 0.10% of their portfolio | 12.4k $343.7k | New |
| Brevan Howard Capital Management LP 0.00% of their portfolio | 11.1k $308.4k | New |
| Jump Financial, LLC 0.00% of their portfolio | 10.9k $302.9k | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 10.9k $302.5k | Added +5.8k |
| XTX Topco Ltd 0.01% of their portfolio | 10.8k $299.3k | New |
| Engineers Gate Manager LP 0.00% of their portfolio | 9.4k $261.5k | Reduced -952 |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 9.2k $254.0k | New |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 8.5k $235.9k | Added +5.0k |
| OMERS ADMINISTRATION Corp 0.00% of their portfolio | 8.1k $224.8k | Reduced -7.5k |
| Virtus Investment Advisers, LLC 0.06% of their portfolio | 7.6k $209.6k | Added +184 |
| CITIGROUP INC 0.00% of their portfolio | 6.5k $179.9k | Added +4.3k |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 4.6k $128.1k | First filing |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 544 $15.1k | Reduced -63 |
| UBS Group AG 0.00% of their portfolio | 364 $10.1k | Reduced -9.4k |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO 0.00% of their portfolio | 260 $7.2k | Unchanged |
| Aquatic Capital Management LLC 0.00% of their portfolio | 220 $6.1k | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 190 $5.3k | Unchanged |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 149 $4.1k | Added +147 |
| Accent Capital Management, LLC 0.00% of their portfolio | 142 $3.9k | New |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 100 $2.8k | Unchanged |
| US BANCORP \DE\ 0.00% of their portfolio | 59 $1.6k | Unchanged |
| FIFTH THIRD BANCORP 0.00% of their portfolio | 57 $1.6k | New |
| EverSource Wealth Advisors, LLC 0.00% of their portfolio | 55 $1.5k | Unchanged |
| Allworth Financial LP 0.00% of their portfolio | 29 $805 | Reduced -3 |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 16 $0 | New |