SEC ownership of Quartzsea Acquisition Corp

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0002047455.

Comparable stake leader

Blue Jay Investment LLC

Disclosed value leader

BERKLEY W R CORP

Comparable rows

16/31

Latest evidence

30 Jun 2026

Top shareholders Insider holders Latest transactions

Public ticker: QSEA, QSEAR, QSEAU on Nasdaq
Parsed ownership sources: 13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder: Blue Jay Investment LLC
Ranking: Comparable ownership first, then disclosed value
Comparable ownership rows: 16 of 31
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder: Blue Jay Investment LLC
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date: 30 Jun 2026
Freshness: Most recent filing date in this holder set
Issuer CIK: 0002047455
Issuer location: New York, NY

Ownership snapshot

Top shareholders of Quartzsea Acquisition Corp (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

Blue Jay Investment LLC

Disclosed value leader

BERKLEY W R CORP

Comparable rows

16/31

Latest evidence

30 Jun 2026

13D/G 3/4/5 13F Lead comparable stake: 27% 15 rows are not safely comparable across share classes. 13D/G row: Blue Jay Investment LLC Showing 1-8 of 31 holder rows.

Quick read

Blue Jay Investment LLC leads the comparable SEC ownership view at 27%.

16 of 31 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 Blue Jay Investment LLC's linked filing trail.

Comparable ownership Top 5

Blue Jay Investment LLC 27%

Karpus Management, Inc. 9.6%

BERKLEY W R CORP 8.9%

MIZUHO FINANCIAL GROUP INC 8%

Feis Equities LLC 5.3%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 31 holder rows

Holder	Evidence	Ownership %	Position	12M Net Δ	As of
Blue Jay Investment LLC	13D/G 3/4/5 10%+ Owner 13D/G 3/4/5	27%	— 3,129,900 shares	$0	19 Mar 2025
Karpus Management, Inc.	13D/G 13F Company 13D/G 13F	9.6%	$10,274,023 974,765 shares	$0	30 Jun 2026
BERKLEY W R CORP	13F 13D/G Company · W. R. Berkley Corporation 13F 13D/G	8.9% from 13D/G	$11,504,861 1,094,190 shares	—	30 Jun 2026
MIZUHO FINANCIAL GROUP INC	13D/G 13D/G	8%	$10,469,340 993,296 shares	$0	30 Jun 2026
Feis Equities LLC	13D/G 13D/G	5.3%	$6,253,375 600,132 shares	+$1,200,061	01 Jun 2026
WOLVERINE ASSET MANAGEMENT LLC	13F 13D/G Company 13F 13D/G	4.9% from 13D/G	$5,228,839 569,600 shares mixed-class rows	—	30 Jun 2026
TD SECURITIES (USA) LLC	13D/G 13D/G	2.5%	$2,884,978 280,095 shares	-$3,423,772	30 Jun 2025
Westchester Capital Management, LLC	13F Company 13F	6%	$6,434,085 611,605 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.

Forms 3/4/5 flow

Insider trading overview

Insider buy and sell flow is broadly balanced over the last 12 months. No Buy or Sell transactions have been reported since 05 Sep 2025.

Buys

Insiders: 0

Sells

Insiders: 0

Net

Shares: 0

Window

Last 12 months

4 rolling buckets

Buy value Sell value

Shares: 0 Shares: 0

Window (months)	Buy value	Sell value	Net value
0-3	$0	$0	$0
3-6	$0	$0	$0
6-9	$0	$0	$0
9-12	$0	$0	$0

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-4 of 4 reporting-owner rows connected to Quartzsea Acquisition Corp. Open a relationship link for the CIK-to-CIK filing trail.

Rows

Largest Forms 3/4/5 holder

Qi Gong

Net 12M change

Latest report

14 Mar 2025

Name	Relationship	Valuation	Report Date
Qi Gong	Chairwoman, CEO, and CFO, Director	Mixed	14 Mar 2025
Wei Zhang	Director	Mixed	14 Mar 2025
Ping Zhang	Director	Mixed	14 Mar 2025
Blue Jay Investment LLC	10%+ Owner	Mixed	14 Mar 2025

Recent insider transactions for Quartzsea Acquisition Corp

Showing up to 300 recent insider transactions from the last 12 months.

Insider	Symbol	Class	Transaction	%	SEC-reported value	SEC-reported price	Shares	Shares owned	Date	Ownership
No insider transactions were found in the last 12 months for this issuer.

^* marks a reported price that did not pass the local price check.