Companies / Acumen Pharmaceuticals, Inc.
Acumen Pharmaceuticals, Inc.
Nasdaq: ABOSCIK 1576885NEWTON, MA
Financials
Ownership
72.3M shares outstanding · as of Aug 7, 2026
Ownership
| Insiders | 0.37% | 269,200 |
| Institutions | 62.96% | 45,528,174 |
| Public float | 36.67% | 26,519,911 |
% of common shares outstanding (exact, from the latest cover-page filing). Institutions are quarterly 13F snapshots; insiders reflect current officers & directors.
Insiders 13
View all →| Insider | % of shares | Shares |
|---|---|---|
OConnell Daniel JosephCEOFormerChief Executive Officer · Director | 1.22% | 881,275 |
Zuga MattFormerCFO & Chief Business Officer | 0.42% | 304,924 |
Siemers EricFormerChief Medical Officer | 0.35% | 255,371 |
Doherty James J.President and CDO | 0.31% | 220,900 |
Barton RussellFormerChief Operating Officer | 0.28% | 205,092 |
Meisner Derek MFormerChief Legal Officer & Corp Sec | 0.24% | 173,999 |
Schacterle AmyFormerChief Regulatory Officer | 0.13% | 92,303 |
Drapkin Kimberlee CDirector | 0.07% | 48,300 |
RA Capital Management, L.P.FormerDirector · 10% owner | 0.07% | 48,300 |
Kolchinsky PeterFormerDirector · 10% owner | — | — |
Institutional holders 73
View all →| Holder | Value | % of shares |
|---|---|---|
| $49.54M | 29.03% | |
| $7.21M | 4.73% | |
| $6.65M | 3.44% | |
| $4.86M | 3.19% | |
| $4.28M | 2.80% | |
| $3.49M | 2.29% | |
| $3.44M | 2.25% | |
| $2.29M | 1.34% | |
| $1.98M | 1.30% | |
| $1.88M | 1.23% |
Activity
Jun 30, 2026View all →
InsidersInstitutions
Who's accumulating and trimming this stock (13F).| Date | Actor | Action | Security | Value | Shares Δ | Position after | Impact |
|---|---|---|---|---|---|---|---|
| Q1 2026 as of | RA Capital Management, L.P. 13F manager | Add | — | $14.30M | +6.1M +40.59% | 20,992,669 29.03% of shares | medium |
| Q2 2026 as of | BlackRock, Inc. 13F manager | Add | — | $6.20M | +2.3M +1369.05% | 2,490,115 3.44% of shares | medium |
| Q2 2026 as of | State Street Corporation 13F manager | Add | — | $1.34M | +500K +499.46% | 600,528 0.83% of shares | low |
| Q1 2026 as of | Two Sigma Investments, LP 13F manager | Add | — | $914.7K | +388K +270.62% | 530,812 0.73% of shares | low |
| Q1 2026 as of | Laurion Capital Management LP 13F manager | Trim | — | $-806.2K | -342K -39.40% | 525,444 0.73% of shares | low |
| Q1 2026 as of | Hudson Bay Capital Management LP 13F manager | Add | — | $575.7K | +244K +33.65% | 968,940 1.34% of shares | low |
| Q1 2026 as of | Marshall Wace, LLP 13F manager | Add | — | $405.9K | +172K +822.60% | 192,889 0.27% of shares | low |
| Q1 2026 as of | Millennium Management LLC 13F manager | Add | — | $178.3K | +76K +12.93% | 659,675 0.91% of shares | low |
5%+ ownership events
Schedule 13D / 13G
| Filer | Stance | % of class |
|---|---|---|
| James B. Murray Jr. | Passive13G | — |
Securities
via CUSIP / OpenFIGI
| Symbol | Type | CUSIP |
|---|---|---|
| ABOS | — | 00509G209 |