ASMB
Assembly Biosciences, Inc.Company with tickers: ASMB
CIK
1426800
CUSIP
045396207
Shares Outstanding
19,817,250
13F Activity (30d)
76 filings
74 filers
Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.
Holders: 75
Total Value: $376,529,147
Total Shares: 13,568,619
Institutional Ownership Trend
Holder Concentration
Across 75 13F filers · Δ vs Dec 31, 2025Top Holder
33.2%
+0.2 pts
Top 5
63.4%
+0.5 pts
Top 10
79.7%
−0.9 pts
HHI
1,409
Broadly held
+7
Quarterly Activity
vs Dec 31, 2025
New
17
Increased
29
Decreased
16
Sold Out
11
Unchanged
13
Holder count:
+6
Institutional value:
-18.9%
Shares held:
-0.6%
Top Buyers
vs Dec 31, 2025| Institution | Added | Now Holds | Open |
|---|---|---|---|
| Small Parkman Healthcare Partners LLC | +161,870 | 411,227 | |
| Mega MILLENNIUM MANAGEMENT LLC | +135,429 | 233,650 | |
| Large Schonfeld Strategic Advisors LLC | +66,265 | 120,500 | |
| Small Seven Fleet Capital Management LP | +51,832 | 56,147 | |
| Large MARSHALL WACE, LLP | +34,325 | 163,400 |
Top Sellers
vs Dec 31, 2025| Institution | Sold | Now Holds | Open |
|---|---|---|---|
| Large Point72 Asset Management, L.P. | −256,504 | 344,105 | |
| Mid Eversept Partners, LP | −118,787 | 40,889 | |
| Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP | −47,445 | 32,949 | |
| Large Caption Management, LLC | −24,750 | 81,841 | |
| Large Blackstone Inc. | −21,899 | 296,855 |
Top New Positions
vs Dec 31, 2025| Institution | Acquired | Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD CAPITAL MANAGEMENT LLC | 490,447 | $13,609,904 | |
| Small HighVista Strategies LLC | 74,735 | $2,073,896 | |
| Mega VANGUARD FIDUCIARY TRUST CO | 71,606 | $1,987,066 | |
| Mega WELLINGTON MANAGEMENT GROUP LLP | 26,496 | $735,263 | |
| Large Squarepoint Ops LLC | 23,804 | $660,561 |
Top Sold-Out Positions
vs Dec 31, 2025| Institution | Previously Held | Last Value (USD) | Open |
|---|---|---|---|
| Mega VANGUARD GROUP INC | 572,898 | $19,484,260 | |
| Mega FRANKLIN RESOURCES INC | 210,528 | $7,160,057 | |
| Small SUPERSTRING CAPITAL MANAGEMENT LP | 65,273 | $2,219,934 | |
| Small Ellsworth Advisors, LLC | 29,735 | $1,011,287 | |
| Small Informed Momentum Co LLC | 29,523 | $1,004,077 |
| Holder | Value (USD) | % of 13F | Shares | Type | Discretion | Filed | Open | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Mid GILEAD SCIENCES, INC. | $125,024,600 | 33.20% | 4,505,391 | Shares | Sole | 2026-05-08 | ||||
| Large FARALLON CAPITAL MANAGEMENT LLC | $34,065,622 | 9.05% | 1,227,590 | Shares | Other | 2026-05-15 | ||||
| Mid RA CAPITAL MANAGEMENT, L.P. | $28,316,377 | 7.52% | 1,020,410 | Shares | Sole | 2026-05-15 | ||||
| Mid Commodore Capital LP | $27,750,000 | 7.37% | 1,000,000 | Shares | Sole | 2026-05-15 | ||||
| Mega JANUS HENDERSON GROUP PLC | $23,568,324 | 6.26% | 849,309 | Shares | Defined | 2026-05-18 | ||||
| Mid Paradigm Biocapital Advisors LP | $18,460,715 | 4.90% | 665,251 | Shares | Sole | 2026-05-15 | ||||
| Mega VANGUARD CAPITAL MANAGEMENT LLC | $13,609,904 | 3.61% | 490,447 | Shares | Defined | 2026-05-15 | ||||
| Small Parkman Healthcare Partners LLC | $11,411,549 | 3.03% | 411,227 | Shares | Sole | 2026-05-15 | ||||
| Large Point72 Asset Management, L.P. | $9,548,913 | 2.54% | 344,105 | Shares | Defined | 2026-05-15 | ||||
| Large Blackstone Inc. | $8,237,726 | 2.19% | 296,855 | Shares | Other | 2026-05-15 | ||||
| Mega MILLENNIUM MANAGEMENT LLC | $6,483,787 | 1.72% | 233,650 | Shares | Sole | 2026-05-15 | ||||
| Mega BlackRock, Inc. | $5,626,116 | 1.49% | 202,743 | Shares | Sole | 2026-05-13 | ||||
| Small STEMPOINT CAPITAL LP | $5,145,821 | 1.37% | 185,435 | Shares | Sole | 2026-05-18 | ||||
| Small B Group, Inc. | $4,875,841 | 1.29% | 175,706 | Shares | Sole | 2026-05-15 | ||||
| Large MARSHALL WACE, LLP | $4,534,350 | 1.20% | 163,400 | Shares | Other | 2026-05-15 | ||||
| Large ADAGE CAPITAL PARTNERS GP, L.L.C. | $4,467,750 | 1.19% | 161,000 | Shares | Sole | 2026-05-15 | ||||
| Small Patient Square Capital LP | $3,782,741 | 1.00% | 136,315 | Shares | Sole | 2026-05-15 | ||||
| Mega GEODE CAPITAL MANAGEMENT, LLC | $3,689,945 | 0.98% | 132,971 | Shares | Defined | 2026-05-15 | ||||
| Large Schonfeld Strategic Advisors LLC | $3,343,875 | 0.89% | 120,500 | Shares | Sole | 2026-05-15 | ||||
| Large Caption Management, LLC | $2,271,087 | 0.60% | 81,841 | Shares | Sole | 2026-05-15 | ||||
| Small HighVista Strategies LLC | $2,073,896 | 0.55% | 74,735 | Shares | Sole | 2026-05-15 | ||||
| Mega VANGUARD FIDUCIARY TRUST CO Bank | $1,987,066 | 0.53% | 71,606 | Shares | Defined | 2026-05-08 | ||||
| Large Qube Research & Technologies Ltd | $1,921,854 | 0.51% | 69,256 | Shares | Sole | 2026-05-15 | ||||
| Mega STATE STREET CORP | $1,573,119 | 0.42% | 56,689 | Shares | Defined | 2026-05-15 | ||||
| Small Seven Fleet Capital Management LP | $1,558,079 | 0.41% | 56,147 | Shares | Sole | 2026-05-15 | ||||
| Mega JPMORGAN CHASE & CO | $1,497,445 | 0.40% | 53,962 | Shares | Defined | 2026-05-13 | ||||
| Small MONIMUS CAPITAL MANAGEMENT, LP | $1,342,822 | 0.36% | 48,390 | Shares | Sole | 2026-05-15 | ||||
| Mid GSA CAPITAL PARTNERS LLP | $1,250,109 | 0.33% | 45,049 | Shares | Sole | 2026-05-08 | ||||
| Mega NORTHERN TRUST CORP Bank | $1,138,138 | 0.30% | 41,014 | Shares | Defined | 2026-05-14 | ||||
| Mid Eversept Partners, LP | $1,134,669 | 0.30% | 40,889 | Shares | Sole | 2026-05-15 | ||||
| Mega ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | $1,094,626 | 0.29% | 39,446 | Shares | Defined | 2026-05-14 | ||||
| Mega GOLDMAN SACHS GROUP INC | $1,004,688 | 0.27% | 36,205 | Shares | Defined | 2026-05-15 | ||||
| Mega JANE STREET GROUP, LLC | $957,347 | 0.25% | 34,499 | Shares | Defined | 2026-05-12 | ||||
| Mega MORGAN STANLEY | $917,275 | 0.24% | 33,055 | Shares | Defined | 2026-05-15 | ||||
| Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP | $914,334 | 0.24% | 32,949 | Shares | Other | 2026-05-15 | ||||
| Mid 683 Capital Management, LLC | $773,198 | 0.21% | 27,863 | Shares | Defined | 2026-05-15 | ||||
| Mega BARCLAYS PLC | $750,637 | 0.20% | 27,050 | Shares | Defined | 2026-05-15 | ||||
| Mega WELLINGTON MANAGEMENT GROUP LLP | $735,263 | 0.20% | 26,496 | Shares | Defined | 2026-05-15 | ||||
| Mega CITADEL ADVISORS LLC | $705,876 | 0.19% | 25,437 | Shares | Defined | 2026-05-15 | ||||
| Large Squarepoint Ops LLC | $660,561 | 0.18% | 23,804 | Shares | Defined | 2026-05-15 | ||||
| Large Trexquant Investment LP | $631,062 | 0.17% | 22,741 | Shares | Sole | 2026-05-15 | ||||
| Large Connor, Clark & Lunn Investment Management Ltd. | $603,867 | 0.16% | 21,761 | Shares | Sole | 2026-05-11 | ||||
| Mega TWO SIGMA INVESTMENTS, LP | $570,262 | 0.15% | 20,550 | Shares | Sole | 2026-05-15 | ||||
| Mid ADAR1 Capital Management, LLC | $553,529 | 0.15% | 19,947 | Shares | Sole | 2026-05-18 | ||||
| Small Palumbo Wealth Management LLC | $545,093 | 0.14% | 19,643 | Shares | Defined | 2026-05-12 | ||||
| Large FEDERATED HERMES, INC. | $524,586 | 0.14% | 18,904 | Shares | Defined | 2026-05-11 | ||||
| Mega VANGUARD PORTFOLIO MANAGEMENT LLC | $491,813 | 0.13% | 17,723 | Shares | Defined | 2026-05-08 | ||||
| Large Hudson Bay Capital Management LP | $466,172 | 0.12% | 16,799 | Shares | Defined | 2026-05-13 | ||||
| Large RENAISSANCE TECHNOLOGIES LLC | $434,315 | 0.12% | 15,651 | Shares | Sole | 2026-05-14 | ||||
| Mid Susquehanna Portfolio Strategies, LLC | $391,275 | 0.10% | 14,100 | Shares | Sole | 2026-05-15 | ||||
| Small EntryPoint Capital, LLC | $343,656 | 0.09% | 12,384 | Shares | Sole | 2026-05-14 | ||||
| Mid Brevan Howard Capital Management LP | $308,358 | 0.08% | 11,112 | Shares | Defined | 2026-05-15 | ||||
| Mid Jump Financial, LLC | $302,946 | 0.08% | 10,917 | Shares | Defined | 2026-05-14 | ||||
| Mega BANK OF AMERICA CORP /DE/ Bank | $302,530 | 0.08% | 10,902 | Shares | Defined | 2026-05-18 | ||||
| Mid XTX Topco Ltd | $299,283 | 0.08% | 10,785 | Shares | Defined | 2026-05-15 | ||||
| Mid Engineers Gate Manager LP | $261,488 | 0.07% | 9,423 | Shares | Sole | 2026-05-15 | ||||
| Mega AMERICAN CENTURY COMPANIES INC | $254,023 | 0.07% | 9,154 | Shares | Defined | 2026-05-15 | ||||
| Mega CANADA PENSION PLAN INVESTMENT BOARD Pension | $235,875 | 0.06% | 8,500 | Shares | Sole | 2026-05-15 | ||||
| Large OMERS ADMINISTRATION Corp | $224,775 | 0.06% | 8,100 | Shares | Sole | 2026-05-15 | ||||
| Small Virtus Investment Advisers, LLC | $209,595 | 0.06% | 7,553 | Shares | Other | 2026-05-14 | ||||
| Mega CITIGROUP INC | $179,903 | 0.05% | 6,483 | Shares | Defined | 2026-05-11 | ||||
| Mega Vanguard Global Advisers, LLC | $128,066 | 0.03% | 4,615 | Shares | Defined | 2026-05-08 | ||||
| Mid Tower Research Capital LLC (TRC) | $15,096 | 0.00% | 544 | Shares | Defined | 2026-05-15 | ||||
| Mega UBS Group AG | $10,101 | 0.00% | 364 | Shares | Defined | 2026-05-05 | ||||
| Large NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO | $7,215 | 0.00% | 260 | Shares | Defined | 2026-05-07 | ||||
| Mid Aquatic Capital Management LLC | $6,105 | 0.00% | 220 | Shares | Sole | 2026-05-15 | ||||
| Mega RHUMBLINE ADVISERS | $5,272 | 0.00% | 190 | Shares | Sole | 2026-05-12 | ||||
| Mega BNP PARIBAS ARBITRAGE, SA | $4,134 | 0.00% | 149 | Shares | Defined | 2026-05-12 | ||||
| Small Accent Capital Management, LLC | $3,940 | 0.00% | 142 | Shares | Sole | 2026-05-11 | ||||
| Large OSAIC HOLDINGS, INC. | $2,775 | 0.00% | 100 | Shares | Defined | 2026-05-15 | ||||
| Large US BANCORP \DE\ Bank | $1,637 | 0.00% | 59 | Shares | Defined | 2026-05-15 | ||||
| Large FIFTH THIRD BANCORP Bank | $1,581 | 0.00% | 57 | Shares | Defined | 2026-05-01 | ||||
| Mid EverSource Wealth Advisors, LLC | $1,526 | 0.00% | 55 | Shares | Sole | 2026-05-18 | ||||
| Mid Allworth Financial LP | $804 | 0.00% | 29 | Shares | Sole | 2026-05-15 | ||||
| Mega ROYAL BANK OF CANADA Bank | $444 | 0.00% | 16 | Shares | Sole | 2026-05-15 | ||||
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