Archimedes Tech SPAC Partners II Co. (ATII) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

30,047,512Shares Outstanding

14,370,155Shares held by institutions

$151,892,538Value of institutional holdings

73.74%Institutional ownership %

0.82%Shares Changed QoQ

48No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

According to SEC filings for the period ending December 2025, Archimedes Tech SPAC Partners II Co. (NASDAQ:ATII) is held by 48 institutional firms.

The collective stake of institutional investors in Archimedes Tech SPAC Partners moved to 73.7% in December 2025, a shift up from the 73.5% reported for September 2025.
In percentage terms, this reflects as a holdings change of 0.82% quarter on quarter, and an unavailable change year over year.
During the quarter, 13 institutions bought more Archimedes Tech SPAC Partners shares, 9 sold shares, and 26 of the 48 total investors held their position steady.
Collectively, institutional investors increased their stake in Archimedes Tech SPAC Partners to 22.16Mn shares as of December 2025, a change that is up by 179.80K shares quarter on quarter and down N/A shares year over year.
As of December 31, 2025, TENOR CAPITAL MANAGEMENT Co., L.P. held Archimedes Tech SPAC Partners's largest shareholding position with over 1.50Mn shares, representing 4.99% of total outstanding shares.
Among the most significant buyers of Archimedes Tech SPAC Partners during December 2025 were L1 Global Manager Pty Ltd (200.00K), RIVERNORTH CAPITAL MANAGEMENT, LLC (90.00K), Baird Financial Group, Inc. (78.50K), Shaolin Capital Management LLC (70.78K), METEORA CAPITAL, LLC (68.53K).
Leading sellers of Archimedes Tech SPAC Partners stock in December 2025 included Sculptor Capital LP (139.35K), WOLVERINE ASSET MANAGEMENT LLC (100.97K), PERISCOPE CAPITAL INC. (51.90K), Schonfeld Strategic Advisors LLC (48.15K), MIZUHO SECURITIES USA LLC (31.27K).
The top 10 institutional holders of Archimedes Tech SPAC Partners for the quarter ending December 2025 included TENOR CAPITAL MANAGEMENT Co., L.P. (1.50Mn), Magnetar Financial LLC (1.30Mn), D. E. Shaw & Co., Inc. (1.14Mn), LINDEN ADVISORS LP (1.00Mn), AQR Arbitrage LLC (964.38K), Westchester Capital Management, LLC (907.14K), GLAZER CAPITAL, LLC (864.30K), LMR Partners LLP (850.00K), Ghisallo Capital Management LLC (800.00K), Governors Lane LP (758.62K).

48 Institutional Holders

14,370,155 Total Shares Held

Rows:

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Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
TENOR CAPITAL MANAGEMENT Co., L.P.	31 Dec, 2025	1,500,000	0	0.00%	$15,540,000.00
Magnetar Financial LLC	31 Dec, 2025	1,300,000	0	0.00%	$13,468,000.00
D. E. Shaw & Co., Inc.	31 Dec, 2025	1,138,500	0	0.00%	$11,794,860.00
LINDEN ADVISORS LP	31 Dec, 2025	1,000,000	0	0.00%	$10,360,000.00
AQR Arbitrage LLC	31 Dec, 2025	964,382	0	0.00%	$9,990,998.00
Westchester Capital Management, LLC	31 Dec, 2025	907,144	7,144	0.79%	$9,398,012.00
GLAZER CAPITAL, LLC	31 Dec, 2025	864,303	-10,784	-1.23%	$8,954.00
LMR Partners LLP	31 Dec, 2025	850,000	0	0.00%	$8,806,000.00
Ghisallo Capital Management LLC	31 Dec, 2025	800,000	0	0.00%	$8,288,000.00
Governors Lane LP	31 Dec, 2025	758,617	8,617	1.15%	$7,859,272.00
Alberta Investment Management Corp	31 Dec, 2025	750,000	0	0.00%	$7,770,000.00
TWO SIGMA INVESTMENTS, LP	31 Dec, 2025	725,000	0	0.00%	$7,511,000.00
METEORA CAPITAL, LLC	31 Dec, 2025	718,433	68,533	10.55%	$7,442,966.00
Hudson Bay Capital Management LP	31 Dec, 2025	700,000	0	0.00%	$7,252,000.00
Radcliffe Capital Management, L.P.	31 Dec, 2025	658,322	46,800	7.65%	$6,820,216.00
Sculptor Capital LP	31 Dec, 2025	600,646	-139,354	-18.83%	$6,222,693.00
DRIEHAUS CAPITAL MANAGEMENT LLC	31 Dec, 2025	573,083	0	0.00%	$5,937,140.00
Jain Global LLC	31 Dec, 2025	500,000	0	0.00%	$5,180,000.00
PICTON MAHONEY ASSET MANAGEMENT	31 Dec, 2025	500,000	0	0.00%	$5,180,000.00
MOORE CAPITAL MANAGEMENT, LP	31 Dec, 2025	450,000	0	0.00%	$4,662,000.00

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