As of November 6, 2026, Acumen Pharmaceuticals, Inc. is a publicly traded company (Nasdaq: ABOS). The largest holder reporting an active stake on Schedule 13D is RA Capital, at 29.5%. No bankruptcy or receivership appears in its SEC Form 8-K filings. Passive holders reporting on Schedule 13G include Sands Capital Alternatives, LLC (5.6%), James B. Murray Jr. (5%) (Schedule 13D/A, March 17, 2026).
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Is Acumen Pharmaceuticals, Inc. a real, registered company?
- Acumen Pharmaceuticals, Inc. files with the SEC under CIK 1576885 (its SEC filings).
- Its shares are listed under the ticker ABOS on Nasdaq (SEC company record).
- Incorporated in Delaware; business address in Newton, Massachusetts, as its SEC filings state.
- Court and bankruptcy records: see Before you sign or pay below.
Before you sign or pay
- Court and bankruptcy: No federal court case or bankruptcy filing found under Acumen Pharmaceuticals, Inc. in our court records and SEC 8-K records (as of 2026-11-06).
- Layoffs: 1 exit or restructuring plan reported on Form 8-K, Item 2.05 (latest filed 2026-11-05, about 52 jobs).
- Ownership: 5%+ holders are reported on Schedule 13D or 13G; the latest names James B. Murray Jr. (filed 2026-04-07).
Who are Acumen Pharmaceuticals, Inc.'s owners and officers?
Acumen Pharmaceuticals, Inc.: incorporated in Delaware; business address in Newton, Massachusetts; industry Biological Products, (No Diagnostic Substances) (Form 8-K, 2026-11-05).
| Report | Holder | Share |
|---|---|---|
| Schedule 13G, 2026-04-07 | James B. Murray Jr. | 5% |
| Schedule 13D/A, 2026-03-17 | Ra Capital Management, L.P. | 29.5% |
| Schedule 13G/A, 2025-11-04 | Franklin Resources, Inc. | 3.8% |
| Schedule 13G/A, 2025-08-13 | Sands Capital Alternatives, LLC | 5.6% |
Questions about who owns Acumen Pharmaceuticals, Inc.
Who owns Acumen Pharmaceuticals, Inc.?
On this page, 3 holders' latest ownership filings report 5% or more of Acumen Pharmaceuticals, Inc.: Ra Capital Management, L.P. (29.5%, Schedule 13D/A, filed 2026-03-17), Sands Capital Alternatives, LLC (5.6%, Schedule 13G/A, filed 2025-08-13) and James B. Murray Jr. (5%, Schedule 13G, filed 2026-04-07).
Who are the largest shareholders of Acumen Pharmaceuticals, Inc.?
By the share each holder's latest filing reports, the largest holders of Acumen Pharmaceuticals, Inc. on this page are Ra Capital Management, L.P. (29.5%), Sands Capital Alternatives, LLC (5.6%) and James B. Murray Jr. (5%).
When did Ra Capital Management, L.P. buy into Acumen Pharmaceuticals, Inc.?
The filings give report dates, not purchase dates. The earliest filing from Ra Capital Management, L.P. on this page is the Schedule 13D/A, filed 2026-03-17, reporting 29.5%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 4 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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What the Full Report on Acumen Pharmaceuticals, Inc. covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
Warning Bells
Sources
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Which insiders own Acumen Pharmaceuticals, Inc. shares?
Directors, officers and holders of 10% or more report their shares on Forms 3, 4 and 5. Each line is the latest such report, largest holding first.
- , the chief executive and a director: 881,275 shares (1.2% of shares outstanding) (Form 4, 2026-01-23).
- , the chief financial officer and chief business officer: 304,924 shares (0.42% of shares outstanding) (Form 4, 2026-01-23).
- , the chief medical officer: 255,371 shares (0.35% of shares outstanding) (Form 4, 2026-01-23).
- , the president and cdo: 220,900 shares (0.31% of shares outstanding) (Form 4, 2026-01-21).
- , a director: 220,624 shares (0.31% of shares outstanding) (Form 4, 2026-06-05).
Shares outstanding: 72,327,320 as of 2026-10-21, from the company's latest SEC cover page.
How much has Acumen Pharmaceuticals, Inc. raised?
No fundraising or offering filing from Acumen Pharmaceuticals, Inc. is on file with us.
Red flags found
1 exit or restructuring plan on Form 8-K (latest Form 8-K, 2026-11-05).
Keep reading
More on Acumen Pharmaceuticals, Inc. and the records around it.
Acumen Pharmaceuticals, Inc. elsewhere on the record
- 5%+ stake filings Apr 2026
Companies that share a holder
- Franklin Resources, Inc. also filed stake reports on 41 other companies: Adicet Bio, Inc. (Oct 2026), ALBEMARLE CORPORATION (Oct 2026), Andersen Group Inc. (Oct 2026)
- RA Capital Management, L.P. also filed stake reports on 100 other companies: Bambusa Therapeutics, Inc. (Nov 2026), SOLID BIOSCIENCES INC. (Nov 2026), LENZ THERAPEUTICS, INC. (Nov 2026)
Related pages
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