Security key
G7387B122
Quantumsphere Acquisition Corp - UNIT 07/30/2030 (QUMSU)
CUSIP: G7387B122
Q3 2026 13F Holders as of 30 Sep 2026
- Security type / class
- Equity / UNIT 07/30/2030
- Total 13F shares
- 125,000
- Total 13F value
- $1,297,500
- Share change
- 0
- SEC-reported price per share
- $10.38
- Number of holders
- 2
Report period
Q3 2026
Institutions
2
Top holders
2
QUMSU full security history
Ownership snapshot
Full 13F holder table
Previous quarter: Q2 2026
Quantumsphere Acquisition Corp SEC filings
Quantumsphere Acquisition Corp company facts
Broader feeds
Reporting periods
Holder history for CUSIP G7387B122
Recent filing periods:
Ownership snapshot
Top reported holders of QUMSU - Quantumsphere Acquisition Corp - UNIT 07/30/2030 (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Whiteowl Holdings LLC
Disclosed value leader
BERKLEY W R CORP
Comparable rows
4/15
Latest evidence
30 Sep 2026
3/4/5
13D/G
13F
Lead comparable stake: 27%
11 rows are not safely comparable across share classes.
13D/G row: Whiteowl Holdings LLC
Showing 1-6 of 15 holder rows.
Quick read
Whiteowl Holdings LLC leads the comparable SEC ownership view at 27%.
4 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Whiteowl Holdings LLC's linked filing trail.
Comparable ownership
Top 4
Whiteowl Holdings LLC
27%
BERKLEY W R CORP
9.5%
MIZUHO FINANCIAL GROUP INC
8.4%
WOLVERINE ASSET MANAGEMENT LLC
3%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Whiteowl Holdings LLC |
3/4/5
13D/G
10%+ Owner
|
27%
Reported 13D/G
· 05 Aug 2025
|
—
3,126,650 shares
|
— | 05 Aug 2025 |
| BERKLEY W R CORP |
13D/G
13F
W. R. Berkley Corporation · Company
|
9.5%
Reported 13D/G
· 30 Sep 2026
|
$11,215,788
1,081,561 shares
|
+$2,075,649 | 30 Sep 2026 |
| MIZUHO FINANCIAL GROUP INC |
13D/G
|
8.4%
Reported 13D/G
· 30 Sep 2026
|
$9,883,201
953,057 shares
|
+$2,436,649 | 30 Sep 2026 |
| WOLVERINE ASSET MANAGEMENT LLC |
13F
13D/G
Company
|
3%
Reported 13D/G
· 30 Sep 2026
|
$6,188,874
735,536 shares
mixed-class rows
|
— | 30 Jun 2026 |
| MIZUHO SECURITIES USA LLC |
13F
Company
|
—
denominator unverified
|
$7,683,783
757,023 shares
|
— | 30 Jun 2026 |
| Karpus Management, Inc. |
13F
Company
|
—
denominator unverified
|
$4,802,123
469,875 shares
|
— | 30 Jun 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q3 2026
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
2
Shares
125,000
Rows available
2
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q3 2026 vs Q2 2026 Across Filers
Q2 2026 holders
7
Q3 2026 holders
2
Holder diff
-5
| Investor | Q2 2026 Shares | Q3 2026 Shares | Share Diff | Share Chg % | Q2 2026 value | Q3 2026 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend