Quantumsphere AcquisitionQUMSU 13F holders, Q3 2025 (September 30) 30 holders
1 famous investor
$10.13 avg. 13F price*
At the end of Q3 2025 , 30 institutions reported holding Quantumsphere Acquisition Co. (QUMSU) in their 13F filings. The largest holders were Rivernorth Capital Management, LLC ($4.3M), Glazer Capital, LLC ($4.3M) and Harraden Circle Investments, LLC ($4.1M). One famous investor held it David E. Shaw (0.0% of D. E. Shaw & Co.'s portfolio).
Company Quantumsphere Acquisition Co.
CUSIP G7387B122
Latest filing quarter Q2 2026 History Number of 13F holders
Total Exit/New Position Q3 2025 Institutions Total Value New Positions 29 $54.5M Exits 0 $0
Ownership 30 holders Portfolio Manager % of Holder's Portfolio Change Shares Value ▼ Rivernorth Capital Management, LLC 0.25% New 425,000 $4.3M Glazer Capital, LLC 0.16% New 420,542 $4.3M Harraden Circle Investments, LLC 0.87% New 400,707 $4.1M Linden Advisors LP 0.38% New 400,000 $4.1M Polar Asset Management Partners Inc. 0.12% New 400,000 $4.1M Toronto Dominion Bank 0.01% New 361,000 $3.7M AQR Arbitrage LLC 0.12% New 322,660 $3.3M HGC Investment Management Inc. 0.75% New 300,000 $3.0M Meteora Capital, LLC 0.26% New 229,999 $2.3M Two Sigma Investments, LP 0.00% New 222,490 $2.3M Clear Street Group Inc. 0.01% — 218,057 $2.2M Cable Car Capital, LP 1.33% New 174,801 $1.8M StoneX Group Inc. 0.07% New 168,149 $1.7M Heights Capital Management, Inc. 0.50% New 150,000 $1.5M Radcliffe Capital Management, L.P. 0.31% New 150,000 $1.5M Wolverine Asset Management LLC 0.11% New 150,000 $1.5M Berkley W R Corp. 0.10% New 148,770 $1.5M Periscope Capital Inc. 0.32% New 125,000 $1.3M D. E. Shaw & Co. 0.00% New 125,000 $1.3M BNP Paribas Financial Markets 0.00% New 102,340 $1.0M Atw Spac Management LLC 1.33% New 100,000 $1.0M Westchester Capital Management, LLC 0.05% New 100,000 $1.0M Boothbay Fund Management, LLC 0.03% New 100,000 $1.0M Schonfeld Strategic Advisors LLC 0.01% New 87,486 $886K GABELLI & Co INVESTMENT ADVISERS, INC. 0.11% New 67,700 $686K Gabelli Funds LLC 0.00% New 57,300 $580K Warberg Asset Management LLC 1.51% New 41,421 $420K HRT Financial LP 0.00% New 29,985 $303K TrueMark Investments, LLC 0.02% New 10,000 $101K JPMorgan Chase & Co. 0.00% New 10,000 $101K
"% of holder's portfolio" is QUMSU's weight in each manager's 13F, not the share of Quantumsphere Acquisition Co. the manager owns.