Archimedes Tech SPAC Partners II Co. Ordinary Shares
Archimedes Tech SPAC Partners II Co. Ordinary Shares (ATII) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ATII · as of Sep 30, 2025
Ownership Breakdown
47
Institutional Holders
▲ 4 vs Q2
$224.95M
Total Inst. Value
▲ $8.97M vs Q2
29.59M
Shares Outstanding
freeFloat 73.71%
22.02M
13F Shares Held
▲ 892,421 vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
ATII largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
TENOR CAPITAL MANAGEMENT CO., L.P. blank checks | 1.50M | 5.07% | 5.07% | $15.32B | Nov 14, 2025 | — held |
MAGNETAR FINANCIAL LLC blank checks | 1.30M | 4.39% | 4.39% | $13.31B | Nov 13, 2025 | — held |
D. E. SHAW & CO., INC. blank checks | 1.14M | 3.85% | 3.85% | $11.64B | Nov 14, 2025 | — held |
LINDEN ADVISORS LP blank checks | 1.00M | 3.38% | 3.38% | $10.23B | Nov 14, 2025 | — held |
AQR ARBITRAGE LLC blank checks | 964.4K | 3.26% | 3.26% | $9.85B | Nov 14, 2025 | ▼ 5.0K |
WESTCHESTER CAPITAL MANAGEMENT, LLC blank checks | 900.0K | 3.04% | 3.04% | $9.19B | Nov 14, 2025 | ▲ 250.0K |
GLAZER CAPITAL, LLC blank checks | 875.1K | 2.96% | 2.96% | $8.94B | Nov 13, 2025 | — held |
LMR PARTNERS LLP blank checks | 850.0K | 2.87% | 2.87% | $8.68B | Nov 14, 2025 | — held |
GHISALLO CAPITAL MANAGEMENT LLC blank checks | 800.0K | 2.70% | 2.70% | $8.19B | Nov 14, 2025 | — held |
GOVERNORS LANE LP blank checks | 750.0K | 2.53% | 2.53% | $7.68B | Nov 14, 2025 | — held |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
5
Increased
+1.28M shares5
New Positions
first time holders11
Decreased
−1.32M shares0
Sold Out
fully exitedNet shares change (top 50)
33.5K
+1.28M / −1.32M
Net new holders
-1
5 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
ATII insider trading · insider activity
Source: SEC Form 4
Recent Insider Transactions
Showing 10 most recent · Common Stock only
No recent insider transactions reported.
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Archimedes Tech SPAC Partners II Co. Ordinary Shares (ATII) is primarily owned by institutional investors, who hold approximately 74.4% of total shares outstanding. Company insiders own approximately 26.29%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Archimedes Tech SPAC Partners II Co. Ordinary Shares is TENOR CAPITAL MANAGEMENT CO., L.P., holding approximately 1.50 million shares — equal to 5.07% of outstanding shares — as of September 30, 2025.
A total of 47 institutional investors currently hold ATII stock, with a combined institutional value of approximately $224,953,929 as of the most recent 13F filing period.
Frequently asked questions
ATII ownershipArchimedes Tech SPAC Partners II Co. Ordinary Shares (ATII) is primarily owned by institutional investors, who hold approximately 74.4% of shares. The largest shareholder is TENOR CAPITAL MANAGEMENT CO., L.P. with a 5.07% stake. Company insiders hold 26.29%. Data sourced from SEC Form 13F as of September 30, 2025.