Acumen Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US00509G2093

SecurityABOS / Acumen Pharmaceuticals, Inc.
InstitutionMorgan Stanley
Latest Disclosed Ownership144,584 shares
Latest Disclosed Value $ 341,219
Morgan Stanley reports 13.37% decrease in ownership of ABOS / Acumen Pharmaceuticals, Inc.

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 144,584 shares of Acumen Pharmaceuticals, Inc. (US:ABOS) valued at $341,218 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 166,905 shares of Acumen Pharmaceuticals, Inc.. This represents a change in shares of -13.37% during the quarter. The current value of the position is $331,097 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

Upgrade to unlock premium data and export to Excel .

Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 144,584 -22,321 -13.37 341 -3.12 0.0000
2026-05-27 2025-12-31 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 166,905 17,504 11.72 352 38.04 0.0000
2026-02-13 2025-12-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 166,905 17,504 352 0.0000
2026-05-27 2025-09-30 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 149,401 -4,347 -2.83 255 43.26 0.0000
2025-11-14 2025-09-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 149,401 -4,347 255 0.0000
2025-08-15 2025-06-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 153,748 1,112 0.73 178 6.59 0.0000
2025-05-15 2025-03-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 152,636 -113,580 -42.66 168 -63.46 0.0000
2025-05-15 2024-12-31 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 266,216 27,016 11.29 458 -22.93 0.0000
2025-02-14 2024-12-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 266,216 27,016 458 0.0000
2025-05-14 2024-09-30 13F/A-2 ACUMEN PHARMACEUTICALS COM 00509G209 239,200 151,391 172.41 593 179.72 0.0000
2025-02-14 2024-09-30 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 239,200 151,391 593 0.0000
2024-11-14 2024-09-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 239,200 151,391 593 0.0000
2025-05-14 2024-06-30 13F/A-2 ACUMEN PHARMACEUTICALS COM 00509G209 87,809 39,097 80.26 212 7.61 0.0000
2024-10-17 2024-06-30 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 87,809 39,097 212 0.0000
2024-08-14 2024-06-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 87,809 39,097 212 0.0000
2024-10-17 2024-03-31 13F/A-2 ACUMEN PHARMACEUTICALS COM 00509G209 48,712 25,586 110.64 197 123.86 0.0000
2024-08-16 2024-03-31 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 48,712 25,586 197 0.0000
2024-05-15 2024-03-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 48,712 25,586 197 0.0000
2024-08-16 2023-12-31 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 23,126 887 3.99 89 -4.35 0.0000
2024-02-13 2023-12-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 23,126 887 89 0.0000
2023-11-15 2023-09-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 22,239 6,915 45.13 92 26.03 0.0000
2023-08-14 2023-06-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 15,324 -36,184 -70.25 74 -65.07 0.0000
2023-05-15 2023-03-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 51,508 25,824 100.55 209 51.45 0.0000
2023-02-14 2022-12-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 25,684 6,770 35.79 139 -26.98 0.0000
2022-11-14 2022-09-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 18,914 -5,283 -21.83 189 65.79 0.0000
2022-10-27 2022-06-30 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 24,197 10,510 76.79 114 115.09 0.0000
2022-08-15 2022-06-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 24,197 10,510 114 0.0000
2022-10-27 2022-03-31 13F/A-1 ACUMEN PHARMACEUTICALS COM 00509G209 13,687 -6,946 -33.66 53 -61.87 0.0000
2022-05-13 2022-03-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 13,687 -6,946 53 0.0000
2022-02-14 2021-12-31 13F ACUMEN PHARMACEUTICALS COM 00509G209 20,633 20,064 3,526.19 139 1,637.50 0.0000
2021-11-15 2021-09-30 13F ACUMEN PHARMACEUTICALS COM 00509G209 569 569 8 0.0000
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.