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Quantumsphere Acquisition Corp. QUMS

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Estimated market cap $114.06M10.94M shares, shares as of Jun 29, 2026CIK 2070900

Insider trades, 12 mo

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No open-market trades

Congress trades, 24 mo

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No disclosed trades

13F holders, Q2 2026

78.5% of shares · 6 added

13F holders

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Lobbying, 12 mo

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No lobbying filings

Federal contracts, 12 mo

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None matched

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Latest 10-Q

Q2 2026

What changed in Quantumsphere Acquisition Corp.'s latest quarterly report, compared with the one before.

Filed Aug 14, 2026 · Quarter ended Jun 30, 2026

Compared with the 10-K for the period ended Mar 31, 2026. Sections compared: management's discussion, risk factors, legal proceedings and controls and procedures.

Read the 10-Q on sec.gov ↗Filing index ↗

Latest 10-Q

What changed in Quantumsphere Acquisition Corp.'s latest quarterly report, compared with the one before.

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Insider trades

Open-market trades from Form 4. 10b5-1 marks a plan set in advance.

No recent insider purchases or sales for this company.

Insider trades

Open-market trades from Form 4. 10b5-1 marks a plan set in advance.

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13F holders

8.59M shares

27 funds report QUMS. Values checked against market prices.

Funds own 79% of shares (Q2 2026)

27 funds hold the stock.

Q3 2026: 33% · 5,560 of ~8,900 funds reported so far

Q3 20257.5%
Q4 202558%
Q1 202666%
Q2 202679%
Q3 2026 (so far)33%

Reports for the quarter ending Sep 30, 2026 are still coming in (11 positions so far, against 28 the quarter before), so we compare the two complete quarters before it.

Q2 2026. 1 new, 6 added to, 10 trimmed, 3 exited since Q1 2026.

Top 13F holders
#
1	Mizuho Securities USA LLC 13F ↗	1.49M	$15.0M	+103.4%
2	Berkley W R Corp 13F ↗	881,402	$9.0M	+73.3%
3	Wolverine Asset Management LLC 13F ↗	602,984	$6.2M	-0.2%
4	Karpus Management, Inc. 13F ↗	469,875	$4.8M	-4.9%
5	Rivernorth Capital Management, LLC 13F ↗	424,124	$4.4M	-0.1%
6	D. E. Shaw & Co., Inc. 13F ↗	409,860	$4.2M	unchanged
7	Shaolin Capital Management LLC 13F ↗	405,761	$4.1M	-15.5%
8	Glazer Capital, LLC 13F ↗	400,089	$4.1M	-5.4%
9	Polar Asset Management Partners Inc. 13F ↗	400,000	$4.1M	unchanged
10	Linden Advisors LP 13F ↗	400,000	$4.1M	unchanged

One of these funds reports its values in thousands of dollars; its figures are shown in dollars.

Download CSV Every fund that holds QUMS, not only these ten. A download holds at most 10,000 rows; narrow the filters to get a smaller slice.

13F holders

Funds that report this stock, checked against market prices.

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Trades by members of Congress

Disclosed in dollar ranges, up to 45 days after the trade.

No recent congressional trades for this company.

Trades by members of Congress

Disclosed in dollar ranges, up to 45 days after the trade.

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Lobbying

What Quantumsphere Acquisition Corp. and its lobbying firms report each quarter.

No recent lobbying filings for this company.

Lobbying

What Quantumsphere Acquisition Corp. and its lobbying firms report each quarter.

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Institutional ownership over time

How many funds reported holding the stock at the end of each quarter, and how many shares they held between them.

Funds holding the stock

Shares they report

Funds holding the stock by quarter

Q3 2025	4	—	851,333	$8.5M
Q4 2025	25	+21	6.57M	$65.7M
Q1 2026	29	+4	7.56M	$76.4M
Q2 2026	27	-2	8.59M	$87.7M
Q3 2026	11	-16	3.58M	$36.9M

Each point is a quarter-end, from Q3 2025 to Q3 2026. A fund's 13F lists its long positions in US-listed securities as of the last day of the quarter and arrives up to 45 days later, so each point shows holdings at quarter-end, not on the day they were reported.

Common shares only; options and bonds are left out. When a fund amends a report, the amended version is the one counted.

The history follows the company's current CUSIP number (G7387B106). If the company's shares were ever re-issued under a different CUSIP, the quarters before the change are not part of this series, so the first point (Q3 2025) can be later than the stock's first appearance in 13F reports.

Share counts are adjusted for stock splits; none took place between these quarters. Values are in dollars as reported at the time and are not adjusted.

A quarter appears once our daily update has built its summary. If a summary cannot be built, older reports are kept and the chart shows the quarters it has until the next update repairs it.

Institutional ownership over time

How many funds reported holding the stock at the end of each quarter, and how many shares they held between them.

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More filings and data

Each opens the table.

Ownership stakes6 in 12 mo 8-K events2 in 90 days PatentsNone on record Short interestFINRA · updated Oct 15 Planned insider salesNone in 12 mo Executive payNone on record Wikipedia attentionNone on record SEC enforcementNone on record Pending deal1 deal filed lately IPO history1 registration Ownership stakes…8-K events…Patents…Short interest…Planned insider sales…Executive pay…Wikipedia attention…SEC enforcement…

About the company

The basics from the company’s SEC registration.

Legal name: Quantumsphere Acquisition Corp
Address: 1185 6TH AVE., SUITE 304, NEW YORK, NY 10036
Phone: 212-612-1400
Fiscal year ends: Mar 31
Filer category: emerging growth company
Incorporated in: Cayman Islands
Listed as: QUMS (Nasdaq), QUMSR (Nasdaq), QUMSU (Nasdaq)
SEC filings: All filings on SEC EDGAR ↗

About the company

The basics from the company’s SEC registration.

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$10.43+$0.02 (+0.14%) Nov 13 close

1M3M1Y

Oct 13, 2026Low $10.38 · High $10.43Nov 13, 2026

Aug 13, 2026Low $10.31 · High $10.43Nov 13, 2026

Nov 13, 2025Low $9.98 · High $10.43Nov 13, 2026

Congress purchase Congress sale Insider sale over $1M

Adjusted for stock splits; not for dividends. Where prices come from.

Live chart

Intraday and historical prices from TradingView. Quotes may be delayed.

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Information, not investment advice. Company matching is automatic; check the source before relying on one row.