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: 20.4m as of 2026-08-07, 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 ≈ $27.46. Options: 3 managers hold calls ($758.4k notional), 1 hold puts ($502.9k).
Trends to Q2 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 |
| Q2 2026 | 93 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| 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 |
| Q2 2026 | 67 | 31 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $11.4m | $0 | 0.00 |
| Q4 2025 | $85.0k | $6.8k | 0.08 |
| Q1 2026 | $5.5k | $0 | 0.00 |
| Q2 2026 | $758.4k | $502.9k | 0.66 |
Biggest buyers
| Paradigm Biocapital Advisors LP | Added | +888.5k |
| BlackRock, Inc. | Added | +564.1k |
| GILEAD SCIENCES, INC. | Added | +471.7k |
| Commodore Capital LP | Added | +415.0k |
| Seven Fleet Capital Management LP | Added | +377.0k |
| FARALLON CAPITAL MANAGEMENT, L.L.C. | Added | +377.0k |
| Parkman Healthcare Partners LLC | Added | +310.0k |
| AMERIPRISE FINANCIAL INC | New | +230.0k |
| Aberdeen Group plc | New | +207.0k |
| Affinity Asset Advisors, LLC | New | +190.0k |
Biggest sellers
| STEMPOINT CAPITAL LP | Reduced | -200.5k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | Sold out | -161.0k |
| MARSHALL WACE, LLP | Reduced | -145.7k |
| Patient Square Capital LP | Sold out | -136.3k |
| Caption Management, LLC | Reduced | -59.0k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | Sold out | -39.4k |
| JANE STREET GROUP, LLC | Sold out | -34.5k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Sold out | -32.9k |
| 683 Capital Management, LLC | Sold out | -27.9k |
| WELLINGTON MANAGEMENT GROUP LLP | Sold out | -26.5k |
Biggest calls
| CITADEL ADVISORS LLC | New | $508.4k18.5k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $239.1k8.7k shares |
| SIMPLEX TRADING, LLC | Added | $11.0k400 shares |
Biggest puts
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $502.9k18.3k shares |
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 since 1 Apr 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 |
|---|---|---|---|---|---|
| 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 | — |
| Q2 2026 | 0 | — | 1 | $674 | — |
| Q3 2026 | 0 | — | 0 | — | — |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-06-17 | Bjorkquist Jeanette M PFO and PAO | Sold | $67429 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, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| GILEAD SCIENCES, INC. 8.30% of their portfolio | 5.0m $136.8m | Added +471.7k |
| FARALLON CAPITAL MANAGEMENT, L.L.C. 0.26% of their portfolio | 1.6m $44.1m | Added +377.0k |
| Paradigm Biocapital Advisors LP 0.80% of their portfolio | 1.6m $42.7m | Added +888.5k |
| Commodore Capital LP 2.32% of their portfolio | 1.4m $38.9m | Added +415.0k |
| RA CAPITAL MANAGEMENT, L.P. 0.24% of their portfolio | 1.0m $28.0m | Unchanged |
| Jupiter Topco LLC 0.01% of their portfolio | 849.3k $23.4m | First filing |
| BlackRock, Inc. 0.00% of their portfolio | 766.8k $21.1m | Added +564.1k |
| Parkman Healthcare Partners LLC 2.04% of their portfolio | 721.2k $19.8m | Added +310.0k |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 558.9k $15.4m | Added +68.5k |
| Point72 Asset Management, L.P. 0.02% of their portfolio | 460.6k $12.7m | Added +116.5k |
| Seven Fleet Capital Management LP 1.96% of their portfolio | 433.1k $11.9m | Added +377.0k |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 298.8k $8.2m | Added +65.2k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 280.4k $7.7m | Added +147.5k |
| Schonfeld Strategic Advisors LLC 0.04% of their portfolio | 242.2k $6.7m | Added +121.7k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 230.0k $6.3m | New |
| DV EQUITIES, LLC 0.90% of their portfolio | 226.4k $6.2m | First filing |
| Aberdeen Group plc 0.01% of their portfolio | 207.0k $5.7m | New |
| Affinity Asset Advisors, LLC 0.26% of their portfolio | 190.0k $5.2m | New |
| B Group, Inc. 2.74% of their portfolio | 175.7k $4.8m | Unchanged |
| STATE STREET CORP 0.00% of their portfolio | 171.9k $4.7m | Added +115.2k |
| STEMPOINT CAPITAL LP 0.81% of their portfolio | 170.4k $4.7m | Reduced -200.5k |
| Squadron Capital Management LLC 1.51% of their portfolio | 160.0k $4.4m | New |
| Woodline Partners LP 0.01% of their portfolio | 150.8k $4.1m | New |
| Driehaus Capital Management LLC 0.02% of their portfolio | 150.0k $4.1m | New |
| Ally Bridge Group (NY) LLC 4.96% of their portfolio | 140.0k $3.8m | New |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 137.8k $3.8m | Added +101.6k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 123.0k $3.4m | Added +82.0k |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 113.2k $3.1m | New |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 95.9k $2.6m | Added +70.5k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 91.2k $2.5m | Added +73.4k |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 74.0k $2.0m | Added +2.4k |
| HighVista Strategies LLC 0.46% of their portfolio | 73.4k $2.0m | Reduced -1.3k |
| Qube Research & Technologies Ltd 0.00% of their portfolio | 51.5k $1.4m | Reduced -17.8k |
| MONIMUS CAPITAL MANAGEMENT, LP 0.33% of their portfolio | 47.6k $1.3m | Reduced -810 |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 46.4k $1.3m | Reduced -7.6k |
| Trexquant Investment LP 0.01% of their portfolio | 45.7k $1.3m | Added +22.9k |
| MORGAN STANLEY 0.00% of their portfolio | 45.2k $1.2m | Added +12.2k |
| GSA CAPITAL PARTNERS LLP 0.07% of their portfolio | 42.9k $1.2m | Reduced -2.1k |
| XTX Topco Ltd 0.02% of their portfolio | 42.9k $1.2m | Added +32.1k |
| UBS Group AG 0.00% of their portfolio | 41.8k $1.1m | Added +41.4k |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 39.4k $1.1m | Added +23.8k |
| Squarepoint Ops LLC 0.00% of their portfolio | 34.2k $940.2k | Added +10.4k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 29.1k $800.4k | New |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 24.2k $665.1k | Added +24.1k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 24.0k $659.9k | New |
| Connor, Clark & Lunn Investment Management Ltd. 0.00% of their portfolio | 23.8k $653.1k | Added +2.0k |
| Caption Management, LLC 0.02% of their portfolio | 22.8k $627.3k | Reduced -59.0k |
| ADAR1 Capital Management, LLC 0.03% of their portfolio | 20.4k $561.9k | Added +500 |
| Palumbo Wealth Management LLC 0.11% of their portfolio | 19.9k $545.9k | Added +222 |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 17.9k $490.7k | Reduced -2.7k |
| Engineers Gate Manager LP 0.01% of their portfolio | 17.8k $488.2k | Added +8.3k |
| MARSHALL WACE, LLP 0.00% of their portfolio | 17.7k $487.4k | Reduced -145.7k |
| HSBC HOLDINGS PLC 0.00% of their portfolio | 16.9k $17.1k | New |
| Nuveen, LLC 0.00% of their portfolio | 16.9k $463.7k | New |
| Eversept Partners, LP 0.02% of their portfolio | 16.5k $453.7k | Reduced -24.4k |
| Susquehanna Portfolio Strategies, LLC 0.01% of their portfolio | 15.1k $415.7k | Added +1.0k |
| Virtus Investment Advisers, LLC 0.09% of their portfolio | 14.3k $391.6k | Added +6.7k |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 13.2k $363.8k | Added +4.1k |
| Invesco Ltd. 0.00% of their portfolio | 11.9k $326.0k | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 11.6k $318.5k | Added +11.4k |
| Integrated Quantitative Investments LLC 0.05% of their portfolio | 10.1k $276.9k | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 9.6k $264.2k | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 9.6k $262.9k | Reduced -1.3k |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 8.5k $233.6k | Unchanged |
| EntryPoint Capital, LLC 0.06% of their portfolio | 8.3k $227.7k | Reduced -4.1k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 8.3k $226.8k | New |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 8.2k $226.0k | New |
| Brevan Howard Capital Management LP 0.00% of their portfolio | 7.8k $213.4k | Reduced -3.3k |
| Persistent Asset Partners Ltd 0.06% of their portfolio | 6.9k $190.8k | New |
| BARCLAYS PLC 0.00% of their portfolio | 6.1k $168.5k | Reduced -20.9k |
| MetLife Investment Management, LLC 0.00% of their portfolio | 5.9k $161.7k | New |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 4.6k $126.8k | Unchanged |
| CITIGROUP INC 0.00% of their portfolio | 4.6k $125.1k | Reduced -1.9k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 4.5k $124.2k | New |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 4.2k $115.4k | New |
| Police & Firemen's Retirement System of New Jersey 0.00% of their portfolio | 2.9k $79.9k | New |
| Legal & General Group Plc 0.00% of their portfolio | 958 $26.3k | New |
| Ameritas Investment Partners, Inc. 0.00% of their portfolio | 895 $24.6k | New |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 788 $21.7k | New |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 530 $14.6k | Reduced -14 |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 440 $12.0k | Added +424 |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO 0.00% of their portfolio | 260 $7.1k | Unchanged |
| Accent Capital Management, LLC 0.00% of their portfolio | 212 $5.8k | Added +70 |
| Sterling Capital Management LLC 0.00% of their portfolio | 199 $5.5k | New |
| Truvestments Capital LLC 0.00% of their portfolio | 193 $5.3k | New |
| FMR LLC 0.00% of their portfolio | 178 $4.9k | New |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 136 $3.7k | New |
| Integrated Wealth Concepts LLC 0.00% of their portfolio | 108 $3.0k | New |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 100 $2.7k | Unchanged |
| Caitong International Asset Management Co., Ltd 0.00% of their portfolio | 75 $2.1k | New |
| Quarry LP 0.00% of their portfolio | 75 $2.1k | New |
| EverSource Wealth Advisors, LLC 0.00% of their portfolio | 55 $1.5k | Unchanged |
| Allworth Financial LP 0.00% of their portfolio | 10 $275 | Reduced -19 |