Archimedes Tech SPAC Partners II Co.

ATIIU

Exchange: Nasdaq
Industry: Blank Checks
SEC CIK: 0002028516

SEC filings (opens in a new tab)

No open-market purchases or sales by Archimedes Tech SPAC Partners II Co. insiders were filed in the last 90 days; 4 institutions reported holding it in 13F filings for Q2 2026, worth $1.32M in total; no superinvestor holds it.

Other share classesATII ATIIW

Q2 2025 vs. Q1 2025

How the institutions holding Archimedes Tech SPAC Partners II Co. changed between Q1 2025 and Q2 2025.

All holders in Q2 2025 All holders in Q1 2025

13F holders of ATIIU: Q1 2025 compared with Q2 2025
Measure	Q1 2025	Of which not filed for Q2 2025	Q2 2025	Change
Holders	44	1	9	−34
Shares	19.3M	600.0K	1.30M	−17.3M (−93.0%)
Value	$194.1M	$6.01M	$13.4M	−$174.7M (−92.9%)

1 institution that held it in Q1 2025 haven't filed for Q2 2025 yet. Not filing isn't selling, so the changes leave them out.

New holders (1)

Institutions that held Archimedes Tech SPAC Partners II Co. at the end of Q2 2025 but not at the end of Q1 2025.

Institutions new to ATIIU in Q2 2025
Institution	Shares	Value	% of portfolio
Toronto Dominion Bank	1	$10	0.00%

Sold out (35)

Institutions that held Archimedes Tech SPAC Partners II Co. at the end of Q1 2025 and filed for Q2 2025 without it.

Institutions that sold out of ATIIU in Q2 2025
Institution	Shares, Q1 2025	Value, Q1 2025
Tenor Capital Management Co., L.P.	1,500,000	$15.2M
CNH Partners LLC	1,303,242	$13.1M
Magnetar Financial LLC	1,300,000	$13.1M
Healthcare of Ontario Pension Plan Trust Fund	1,000,000	$10.1M
Linden Advisors LP	1,000,000	$10.1M
LMR Partners LLP	850,000	$8.56M
Glazer Capital, LLC	839,370	$8.46M
CSS LLC	820,803	$8.27M
Ghisallo Capital Management LLC	800,000	$8.06M
Two Sigma Investments, LP	725,000	$7.31M
Hudson Bay Capital Management LP	700,000	$7.07M
Shaolin Capital Management LLC	650,531	$6.55M
D. E. Shaw & Co., Inc.	575,000	$5.81M
Moore Capital Management, LP	450,000	$4.54M
Westchester Capital Management, LLC	400,000	$4.03M
Schonfeld Strategic Advisors LLC	350,000	$3.53M
K2 Principal Fund, L.P.	319,790	$3.22M
Periscope Capital Inc.	300,000	$3.03M
Mint Tower Capital Management B.V.	300,000	$3.02M
Verition Fund Management LLC	291,500	$2.94M
Aristeia Capital LLC	250,000	$2.52M
Picton Mahoney Asset Management	250,000	$2.52M
Crossingbridge Advisors, LLC	250,000	$2.52M
Whitebox Advisors LLC	250,000	$2.52M
Berkley W R Corp	228,206	$2.30M
Boothbay Fund Management, LLC	218,600	$2.21M
Atw Spac Management LLC	218,600	$2.20M
Centiva Capital, LP	150,000	$1.51M
DLD Asset Management, LP	150,000	$1.51M
Parallax Volatility Advisers, L.P.	100,000	$1.01M
Gritstone Asset Management LLC	100,000	$1.01M
Wealthspring Capital LLC	77,376	$780.0K
Wolverine Asset Management LLC	25,900	$260.8K
Highbridge Capital Management LLC	25,000	$252.5K
Warberg Asset Management LLC	10,000	$100.9K

Not filed for Q2 2025 yet (1)

Institutions that held Archimedes Tech SPAC Partners II Co. at the end of Q1 2025 and haven't filed a 13F for Q2 2025. Not filing isn't selling, so they aren't counted as sold out.

Institutions holding ATIIU in Q1 2025 that haven't filed for Q2 2025
Institution	Shares, Q1 2025	Value, Q1 2025
Mizuho Securities USA LLC	600,000	$6.01M