Security Snapshot

Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share (ABOS) Institutional Ownership

CUSIP: 00509G209

13F Institutional Holders and Ownership History from Q3 2021 to Q1 2026

Latest Period

Q4 2025

Institutions Reporting

70

Shares (Excl. Options)

35,659,733

Price

$2.11

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Type / Class
Equity / Common Stock, $0.0001 par value per share
Symbol
ABOS on Nasdaq
Shares outstanding
72,227,200
Price per share
$2.36
All holders as of 31 Dec 2025
Q4 2025
Total 13F shares
35,659,733
Total reported value
$75,239,476
% of total 13F portfolios
0%
Share change
-32,682
Value change
-$34,280
Number of holders
70
Price from insider filings
$2.36
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors

Quick Takeaways

  • ABOS - Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share is tracked under CUSIP 00509G209.
  • 70 institutions reported positions in Q4 2025.
  • 4 significant owners is listed from Schedule 13D/13G reporting.

What Changed

  • Holder count moved from 70 to 4 between Q4 2025 and Q1 2026.
  • Reported value moved from $75,239,476 to $1,854,450.

Why This Matters

  • You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
  • 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.

Source Evidence

Source: SEC Form 13F

Latest holder context comes from 70 institutions filings for Q4 2025.

Open SEC Evidence

Investment Quick Answers

What is CUSIP 00509G209?
CUSIP 00509G209 identifies ABOS - Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share in SEC 13F datasets.

Where can I see the latest institutional holders?
Review the Q4 2025 holders report and the ownership history table below.

Significant Owners of Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share (ABOS) based on Schedule 13D/G filings

Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
RA CAPITAL MANAGEMENT, L.P. 30% +19% $55,075,356 +$15,883,432 21,101,669 +41% RA Capital Management, L.P. 13 Mar 2026
MURRAY JAMES B JR 5% $9,425,650 3,611,360 James B. Murray Jr. 04 Apr 2025
Sands Capital Alternatives, LLC 5.6% $3,861,295 3,417,075 Sands Capital Alternatives, LLC 30 Jun 2025
FRANKLIN RESOURCES INC 3.8% $3,941,714 2,305,096 Franklin Resources, Inc. 30 Sep 2025

As of 31 Dec 2025, 70 institutional investors reported holding 35,659,733 shares of Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share (ABOS). This represents 49% of the company’s total 72,227,200 outstanding shares.

Top 25 Institutional Shareholders

The largest institutional shareholders of Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share (ABOS) together control 48% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.

Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
RA CAPITAL MANAGEMENT, L.P. 21% 14,932,063 0% 0.32% $31,506,653
Sands Capital Alternatives, LLC 4.7% 3,417,075 0% 1.4% $7,210,028
FRANKLIN RESOURCES INC 3.2% 2,305,096 0% 0% $4,863,753
FMR LLC 2.8% 2,027,497 -0.09% 0% $4,278,019
VANGUARD GROUP INC 2.3% 1,653,772 +0.14% 0% $3,489,459
Knollwood Investment Advisory, LLC 2.3% 1,628,510 0% 0.32% $3,436,156
Alyeska Investment Group, L.P. 1.3% 939,603 0% 0.01% $1,982,562
ADAR1 Capital Management, LLC 1.2% 891,183 0% 0.14% $1,880,396
Laurion Capital Management LP 1.2% 867,046 0% 0.12% $1,829,467
Pathstone Holdings, LLC 1.2% 859,110 0% 0.01% $1,812,722
Hudson Bay Capital Management LP 1% 725,000 -0% 0.01% $1,529,750
MILLENNIUM MANAGEMENT LLC 0.81% 584,143 -2.9% 0% $1,232,542
RENAISSANCE TECHNOLOGIES LLC 0.59% 423,100 -28% 0% $892,741
TWO SIGMA ADVISERS, LP 0.58% 421,800 -0.42% 0% $889,998
GEODE CAPITAL MANAGEMENT, LLC 0.57% 410,206 +2.9% 0% $865,686
SG Americas Securities, LLC 0.56% 401,047 -0.7% 0% $846,000
SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.52% 373,198 +74% 0% $787,448
CITADEL ADVISORS LLC 0.48% 345,283 -30% 0% $728,547
Ikarian Capital, LLC 0.35% 254,312 -4.3% 0.07% $536,599
BANK OF AMERICA CORP /DE/ 0.33% 240,152 +12% 0% $506,720
BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.24% 170,171 -11% 0.01% $359,061
BlackRock, Inc. 0.23% 169,505 -3% 0% $357,655
MORGAN STANLEY 0.23% 166,905 +12% 0% $352,169
ACADIAN ASSET MANAGEMENT LLC 0.21% 152,780 +96% 0% $320,000
TWO SIGMA INVESTMENTS, LP 0.2% 143,221 -28% 0% $302,196

Institutional Holders of Acumen Pharmaceuticals, Inc. - Common Stock, $0.0001 par value per share (ABOS) across Reporting Periods

Period Reported Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2026 Q1 785,957 $1,854,450 +$750,778 $2.36 4
2025 Q4 35,659,733 $75,239,476 -$34,280 $2.11 70
2025 Q3 35,732,361 $61,097,340 -$2,875,631 $1.71 68
2025 Q2 37,585,884 $43,599,129 -$2,103,479 $1.16 69
2025 Q1 39,403,584 $43,344,870 -$3,628,850 $1.10 79
2024 Q4 42,499,401 $73,099,738 -$2,305,406 $1.72 78
2024 Q3 43,605,225 $107,681,203 -$212,803 $2.48 72
2024 Q2 43,581,156 $105,487,337 -$2,322,503 $2.42 81
2024 Q1 43,364,829 $175,565,762 +$20,042,386 $4.05 78
2023 Q4 38,441,008 $147,599,716 -$20,522,527 $3.84 67
2023 Q3 43,186,479 $179,213,677 +$71,103,757 $4.15 64
2023 Q2 26,328,948 $126,640,120 -$5,262,013 $4.81 52
2023 Q1 27,781,261 $112,787,020 -$4,579,764 $4.06 61
2022 Q4 28,727,743 $155,145,749 -$5,374,332 $5.40 59
2022 Q3 27,496,751 $275,793,298 +$19,526,193 $10.03 48
2022 Q2 25,628,401 $120,458,000 -$6,031,616 $4.70 44
2022 Q1 27,062,428 $105,815,702 -$3,031,020 $3.91 53
2021 Q4 25,569,796 $172,840,000 -$1,670,403 $6.76 50
2021 Q3 24,050,108 $357,352,000 +$306,574,000 $14.86 40