Acumen Pharmaceuticals, Inc.: which funds bought and sold

Institutions that bought and sold Acumen Pharmaceuticals shares in Q2 2026, from the holdings they reported to the SEC on Form 13F for March 31, 2026 and June 30, 2026.

Between March 31, 2026 and June 30, 2026, 51 institutions that filed 13F reports for both quarters added to or opened positions in Acumen Pharmaceuticals, and 32 cut or closed them. Together they added a net 1.9M shares, +4.0% on what they held at the start of the quarter. Active managers and hedge funds on our list were net sellers of 2.1M shares (−6.4%); index fund managers were net buyers of 4.5M shares (+178.1%). 30 opened a new position and 17 sold out entirely.

Bought, Q2 2026 51 institutions, 30 of them new holders Sold, Q2 2026 32 institutions, 17 of them sold out

Net change, all compared +1.9M shares (+4.0%)

Net change, active managers −2.1M shares (−6.4%), 9 bought, 11 sold

Buyers versus sellers

institutions compared, 113

51 bought 30 32 sold

Active managers and hedge funds 9 bought · 11 sold · −2.1M

Index fund managers 9 bought · 0 sold · +4.5M

Other institutions 33 bought · 21 sold · −512K

Biggest buyers

by change in shares held

Biggest buyers
Institution	Change in shares	Shares June 30, 2026	Value
Blackrock, Inc. Index funds	+2.3M +1296.4%	2.5M	$6.6M
Geode Capital Management, LLC Index funds	+726K +174.3%	1.1M	$3M
State Street Corp Index funds	+449K +295.8%	601K	$1.6M
Vanguard Portfolio Management LLC Index funds	+321K New position	321K	$856,523
Northern Trust Corp Index funds	+286K +379.6%	361K	$963,187
Renaissance Technologies LLC Hedge fund	+201K +42.4%	675K	$1.8M
Nomura Holdings Inc	+190K New position	190K	$506,531
Dimensional Fund Advisors LP	+172K +143.5%	292K	$778,969
Vanguard Capital Management LLC Index funds	+166K +11.0%	1.7M	$4.5M
Bank Of New York Mellon Corp	+124K New position	124K	$332,086
Charles Schwab Investment Management Inc Index funds	+115K New position	115K	$307,314
Two Sigma Investments, LP Hedge fund	+92K +17.3%	623K	$1.7M
Vanguard Fiduciary Trust Co Index funds	+92K +46.2%	291K	$777,611
Acadian Asset Management LLC Active manager	+84K +45.5%	270K	$718,000
Nuveen, LLC	+63K New position	63K	$169,158
Citadel Advisors LLC Hedge fund	+51K New position	51K	$136,301
Deutsche Bank Ag\	+46K New position	46K	$123,172
Wells Fargo & Company	+40K +391.6%	50K	$132,661
Price T Rowe Associates Inc Active manager	+39K New position	39K	$106,000
Squarepoint Ops LLC Hedge fund	+37K +248.7%	52K	$139,777

Biggest buyers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
Renaissance Technologies LLC Hedge fund	+201K +42.4%	675K	$1.8M
Two Sigma Investments, LP Hedge fund	+92K +17.3%	623K	$1.7M
Acadian Asset Management LLC Active manager	+84K +45.5%	270K	$718,000
Citadel Advisors LLC Hedge fund	+51K New position	51K	$136,301
Price T Rowe Associates Inc Active manager	+39K New position	39K	$106,000
Squarepoint Ops LLC Hedge fund	+37K +248.7%	52K	$139,777
Balyasny Asset Management L.P. Hedge fund	+12K New position	12K	$31,698
Intech Investment Management LLC Active manager	+10K New position	10K	$27,891
American Century Companies Inc Active manager	+6,207 +34.6%	24K	$64,443

Biggest sellers

by change in shares held

Biggest sellers
Institution	Change in shares	Shares June 30, 2026	Value
FMR LLC Active manager	−1.1M −99.3%	7,530	$20,106
SG Americas Securities, LLC	−719K Sold out	0	—
Millennium Management LLC Hedge fund	−599K −90.8%	61K	$161,797
Laurion Capital Management LP Hedge fund	−525K Sold out	0	—
Susquehanna International Group, LLP	−475K −79.0%	126K	$336,698
Marshall Wace, LLP Hedge fund	−145K −75.1%	48K	$128,465
Jane Street Group, LLC	−90K Sold out	0	—
Qube Research & Technologies Ltd Hedge fund	−82K −67.9%	39K	$103,099
Point72 Asset Management, L.P. Hedge fund	−67K Sold out	0	—
Catalyst Funds Management Pty Ltd	−46K Sold out	0	—
Bank Of America Corp	−45K −14.2%	275K	$733,665
ADAR1 Capital Management, LLC Hedge fund	−45K −2.1%	2.1M	$5.6M
Omers Administration Corp	−29K Sold out	0	—
Goldman Sachs Group Inc	−23K −11.0%	184K	$491,085
Simplex Trading, LLC	−17K Sold out	0	—
Captrust Financial Advisors	−16K Sold out	0	—
Brevan Howard Capital Management LP Hedge fund	−15K Sold out	0	—
Hudson Bay Capital Management LP Hedge fund	−14K −1.4%	955K	$2.5M
HRT Financial LP	−13K Sold out	0	—
Jacobs Levy Equity Management, Inc Active manager	−13K Sold out	0	—

Biggest sellers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
FMR LLC Active manager	−1.1M −99.3%	7,530	$20,106
Millennium Management LLC Hedge fund	−599K −90.8%	61K	$161,797
Laurion Capital Management LP Hedge fund	−525K Sold out	0	—
Marshall Wace, LLP Hedge fund	−145K −75.1%	48K	$128,465
Qube Research & Technologies Ltd Hedge fund	−82K −67.9%	39K	$103,099
Point72 Asset Management, L.P. Hedge fund	−67K Sold out	0	—
ADAR1 Capital Management, LLC Hedge fund	−45K −2.1%	2.1M	$5.6M
Brevan Howard Capital Management LP Hedge fund	−15K Sold out	0	—
Hudson Bay Capital Management LP Hedge fund	−14K −1.4%	955K	$2.5M
Jacobs Levy Equity Management, Inc Active manager	−13K Sold out	0	—

New positions

largest by value

Institution	Shares	Value June 30, 2026
Vanguard Portfolio Management LLCIndex funds	321K	$856,523
Nomura Holdings Inc	190K	$506,531
Bank Of New York Mellon Corp	124K	$332,086
Charles Schwab Investment Management IncIndex funds	115K	$307,314
Nuveen, LLC	63K	$169,158
Citadel Advisors LLCHedge fund	51K	$136,301
Deutsche Bank Ag\	46K	$123,172
Price T Rowe Associates IncActive manager	39K	$106,000
New York State Common Retirement Fund	36K	$96,654
Rhumbline AdvisersIndex funds	35K	$93,535

Sold out

largest by value

Institution	Shares	Value March 31, 2026
SG Americas Securities, LLC	719K	$1.7M
Laurion Capital Management LPHedge fund	525K	$1.2M
Jane Street Group, LLC	90K	$211,599
Point72 Asset Management, L.P.Hedge fund	67K	$159,005
Catalyst Funds Management Pty Ltd	46K	$107,616
Omers Administration Corp	29K	$67,496
Simplex Trading, LLC	17K	$41,097
Captrust Financial Advisors	16K	$37,187
Brevan Howard Capital Management LPHedge fund	15K	$36,309
HRT Financial LP	13K	$31,000

Who holds the shares

13F holdings at June 30, 2026

Institutions reporting: 96
Ten largest holders: 82.7%
Index fund managers: 14.7%
Active managers and hedge funds: 65.2%

Buying and selling by type of institution, March 31, 2026 to June 30, 2026
Type	Bought	Sold	New	Sold out	Net change in shares	Net %
Active managers and hedge funds	9	11	4	5	−2.1M	−6.4%
Index fund managers	9	0	3	0	+4.5M	+178.1%
Other institutions	33	21	23	12	−512K	−5.0%

Active managers and hedge funds: a list we maintain of about 400 well-known stock-picking firms and hedge funds, matched by SEC registration number (CIK) and checked against the filer names each quarter. Index fund managers: the large index houses, such as BlackRock, Vanguard, State Street, Geode and Northern Trust. Every other filer (banks, brokers, wealth managers, pension funds, insurers and firms not on the list) counts as another institution. A firm that files under several SEC registrations appears once for each.

What these filings can and cannot tell you

Form 13F lists the long positions in US-listed shares held by investment managers with more than $100 million in such holdings. Managers file it up to 45 days after each quarter ends, so this page shows what funds held at the end of each quarter, not what they are doing now: a position may have changed since. Short positions, most derivatives and smaller managers are not included, and a cut can mean a fund lost clients or rebalanced rather than a view on Acumen Pharmaceuticals.

Only managers that filed a holdings report for both quarters are compared (113 here). 1 other holder is left out: first-time or late filers, firms that changed their SEC registration, and filings that withheld positions under confidential treatment, any of which would otherwise look like a new position or a sale. Figures are as reported by each manager in the SEC's quarterly 13F data sets; option positions are excluded.

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