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Quantumsphere Acquisition Corp

QUMSU
Exchange
Nasdaq
Industry
Blank Checks
SEC CIK
0002070900

No open-market purchases or sales by Quantumsphere Acquisition Corp insiders were filed in the last 90 days; 7 institutions reported holding it in 13F filings for Q2 2026, worth $1.95M in total; no superinvestor holds it.

Other share classesQUMSQUMSR

Q3 2025 vs. Q2 2025

How the institutions holding Quantumsphere Acquisition Corp changed between Q2 2025 and Q3 2025.

All holders in Q3 2025All holders in Q2 2025

13F holders of QUMSU: Q2 2025 compared with Q3 2025
MeasureQ2 2025Q3 2025Change
Holders030+30
Shares05.60M+5.60M
Value$0$56.7M+$56.7M

New holders (30)

Institutions that held Quantumsphere Acquisition Corp at the end of Q3 2025 but not at the end of Q2 2025.

Institutions new to QUMSU in Q3 2025
InstitutionSharesValue% of portfolio
Rivernorth Capital Management, LLC425,000$4.31M0.25%
Glazer Capital, LLC420,542$4.26M0.14%
Harraden Circle Investments, LLC400,707$4.06M0.80%
Linden Advisors LP400,000$4.05M0.03%
Polar Asset Management Partners Inc.400,000$4.05M0.08%
Toronto Dominion Bank361,000$3.66M0.01%
CNH Partners LLC322,660$3.27M0.08%
HGC Investment Management Inc.300,000$3.04M0.74%
Meteora Capital, LLC229,999$2.33M0.25%
Two Sigma Investments, LP222,490$2.25M0.00%
Clear Street Group Inc.218,057$2.21M0.01%
Cable Car Capital LLC174,801$1.77M0.76%
StoneX Group Inc.168,149$1.70M0.07%
Heights Capital Management, Inc150,000$1.52M0.48%
Radcliffe Capital Management, L.P.150,000$1.52M0.09%
Wolverine Asset Management LLC150,000$1.52M0.02%
Berkley W R Corp148,770$1.51M0.10%
D. E. Shaw & Co., Inc.125,000$1.27M0.00%
Periscope Capital Inc.125,000$1.27M0.31%
BNP Paribas Arbitrage, SA102,340$1.04M0.00%
Westchester Capital Management, LLC100,000$1.01M0.05%
Boothbay Fund Management, LLC100,000$1.01M0.03%
Atw Spac Management LLC100,000$1.01M1.28%
Schonfeld Strategic Advisors LLC87,486$886.2K0.01%
Gabelli & Co Investment Advisers, Inc.67,700$685.8K0.11%
Gabelli Funds LLC57,300$580.4K0.00%
Warberg Asset Management LLC41,421$419.6K0.12%
HRT Financial LP29,985$303.0K0.00%
JPMorgan Chase & Co10,000$101.3K0.00%
TrueMark Investments, LLC10,000$101.3K0.02%

Sold out (0)

Institutions that held Quantumsphere Acquisition Corp at the end of Q2 2025 and filed for Q3 2025 without it.

None.