Acumen Pharmaceuticals
Develops sabirnetug, an investigational antibody for early symptomatic Alzheimer’s disease.
$2.92
After-hours close+0.00 (+0.17%)
At close$2.92(−3.80%)
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Breakdown13F · Form 4
Institutions 63.69%46.00M sharesInsiders 3.69%2.67M sharesOther 32.62%23.56M shares
Shares outstanding 72.23M · Float 61.67M · 85.4% free float
Institutions13F, as of Mar 31, 2026
89 holders · 46.00M shares · 22 new positions · 52 increased · 13 reduced · 7 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| Ra Capital Management, L.P. | 20.99M | 29.06% | +6.06M | May 15, 2026 |
| Sands Capital Ventures, LLC | 3.72M | 5.15% | +303.0K | May 8, 2026 |
| Alyeska Investment Group, L.P. | 2.45M | 3.40% | +1.52M | May 15, 2026 |
| Franklin Resources Inc | 2.31M | 3.19% | 0 | May 13, 2026 |
| Adar1 Capital Management, LLC | 2.16M | 2.99% | +1.27M | May 18, 2026 |
| Knollwood Investment Advisory, LLC | 1.63M | 2.25% | 0 | May 14, 2026 |
| Vanguard Capital Management LLC | 1.51M | 2.09% | +1.51Mnew | May 15, 2026 |
| FMR LLC | 1.16M | 1.60% | −870.2K | May 15, 2026 |
Beneficial owners13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| RA Capital Management, L.P.incl. RA Capital Healthcare Fund, L.P., Peter Kolchinsky +1 more | 29.50% | 21.10M | 13D | Mar 17, 2026 ↗ |
| Sands Capital Alternatives, LLC | 5.60% | 3.42M | 13G | Aug 13, 2025 ↗ |
| James B. Murray Jr. | 5.00% | 3.61M | 13G | Apr 7, 2026 ↗ |
InsidersForm 4
| Insider | Role | Shares | % outstanding | Filed |
|---|---|---|---|---|
| Daniel Joseph OConnell | director, officer: Chief Executive Officer | 881.3K | 1.22% | Jan 23, 2026 |
| Matt Zuga | officer: CFO & Chief Business Officer | 304.9K | 0.42% | Jan 23, 2026 |
| Eric Siemers | officer: Chief Medical Officer | 255.4K | 0.35% | Jan 23, 2026 |
| James J. Doherty | officer: President and CDO | 220.9K | 0.31% | Jan 21, 2026 |
| John A. III Stalfort | director | 220.6K | 0.31% | Jun 5, 2026 |
| Russell Barton | officer: Chief Operating Officer | 205.1K | 0.28% | Jan 23, 2026 |
| Derek M. Meisner | officer: Chief Legal Officer & Corp Sec | 174.0K | 0.24% | Mar 10, 2026 |
| Amy Schacterle | officer: Chief Regulatory Officer | 92.3K | 0.13% | Jan 21, 2026 |
| Kimberlee C. Drapkin | director | 48.3K | 0.07% | Jun 5, 2026 |
| Jeffrey L. Ives | director | 48.3K | 0.07% | Jun 5, 2026 |
3 ten-percent owners hold 2.91M shares by Form 4, outside the officers-and-directors figure above · 3 people have not refiled in the last 18 months (194.0K shares), so they are not in the figure above
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Jun 16, 2026 | Derrell Porterdirector | Sale | 12,800 | $2.33 | 35,500 |
| Jun 17, 2026 | Derrell Porterdirector | Sale | 13,040 | $2.33 | 35,500 |
| Jun 15, 2026 | Derrell Porterdirector | Sale | 6,460 | $2.35 | 48,300 |
| Jun 9, 2026 | Nathan B. Fountaindirector | Sale | 6,400 | $2.23 | 48,150 |
| Mar 6, 2026 | Derek M. Meisnerofficer: Chief Legal Officer & Corp Sec | Sale | 2,090 | $3.26 | 173,999 |
| Feb 27, 2026 | Derek M. Meisnerofficer: Chief Legal Officer & Corp Sec | Sale | 9,406 | $3.01 | 173,999 |
| Jan 26, 2026 | Derek M. Meisnerofficer: Chief Legal Officer & Corp Sec | Sale | 15,085 | $3.00 | 173,999 |
| Jan 28, 2026 | Derek M. Meisnerofficer: Chief Legal Officer & Corp Sec | Sale | 2,671 | $3.00 | 173,999 |
| Jan 22, 2026 | Russell Bartonofficer: Chief Operating Officer | Sale | 462 | $1.84 | 205,092 |
| Jan 21, 2026 | Russell Bartonofficer: Chief Operating Officer | Sale | 2,315 | $1.81 | 205,554 |
CongressHouse and Senate disclosures
Not reported.