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Archimedes Tech SPAC Partners II Co.

ATII
Exchange
Nasdaq
Industry
Blank Checks
SEC CIK
0002028516

No open-market purchases or sales by Archimedes Tech SPAC Partners II Co. insiders were filed in the last 90 days; 50 institutions reported holding it in 13F filings for Q2 2026, worth $189.6M in total; no superinvestor holds it.

Other share classesATIIUATIIW

13F holders, Q3 2025

Institutional positions in Archimedes Tech SPAC Partners II Co. as of Sep 30, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
46
+5 vs. Q2 2025
Shares held
22.0M
+930.0K (+4.4%) vs. Q2 2025
Total value
$225.0M
+$9.36M (+4.3%) vs. Q2 2025
New holders
5
5 more added
Sold out
0
11 more reduced

1 institution that held it in Q2 2025 haven't filed for Q3 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q2 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting ATII on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ3 2025: 46 institutions
Q1 2021: 0 institutionsQ2 2021: 0 institutionsQ3 2021: 0 institutionsQ4 2021: 0 institutionsQ1 2022: 0 institutionsQ2 2022: 0 institutionsQ3 2022: 0 institutionsQ4 2022: 0 institutionsQ1 2023: 0 institutionsQ2 2023: 0 institutionsQ3 2023: 0 institutionsQ4 2023: 0 institutionsQ1 2024: 0 institutionsQ2 2024: 0 institutionsQ3 2024: 0 institutionsQ4 2024: 0 institutionsQ1 2025: 0 institutionsQ2 2025: 42 institutionsQ3 2025: 46 institutionsQ4 2025: 49 institutionsQ1 2026: 54 institutionsQ2 2026: 50 institutions
Value heldQ3 2025: $225.0M
Q1 2021: $0Q2 2021: $0Q3 2021: $0Q4 2021: $0Q1 2022: $0Q2 2022: $0Q3 2022: $0Q4 2022: $0Q1 2023: $0Q2 2023: $0Q3 2023: $0Q4 2023: $0Q1 2024: $0Q2 2024: $0Q3 2024: $0Q4 2024: $0Q1 2025: $0Q2 2025: $216.0MQ3 2025: $225.0MQ4 2025: $230.4MQ1 2026: $231.3MQ2 2026: $189.6M
Institutions holding ATII and their total value by quarter
QuarterHoldersValue
Q2 202650$189.6M
Q1 202654$231.3M
Q4 202549$230.4M
Q3 202546$225.0M
Q2 202542$216.0M
Q1 20250$0
Q4 20240$0
Q3 20240$0
Q2 20240$0
Q1 20240$0
Q4 20230$0
Q3 20230$0
Q2 20230$0
Q1 20230$0
Q4 20220$0
Q3 20220$0
Q2 20220$0
Q1 20220$0
Q4 20210$0
Q3 20210$0
Q2 20210$0
Q1 20210$0

Institutions, Q3 2025

Shares, value and share of portfolio for each institution holding Archimedes Tech SPAC Partners II Co.; share changes are against Q2 2025.

Institutions holding ATII in Q3 2025
InstitutionSharesValue% of portfolioChange in sharesAction
Morgan Stanley51$5210.00%−70−57.9%Reduced
Warberg Asset Management LLC10,000$102.3K0.03%00.0%Unchanged
Clear Street Group Inc.29,195$298.1K0.00%+29,195New
CSS LLC50,000$510.5K0.03%00.0%Unchanged
Gritstone Asset Management LLC99,081$1.01M1.04%−919−0.9%Reduced
K2 Principal Fund, L.P.113,670$1.16M0.12%−46,500−29.0%Reduced
MMCAP International Inc. SPC125,000$1.28M0.15%+125,000New
Readystate Asset Management LP147,534$1.51M0.07%+147,534New
Toronto Dominion Bank150,000$1.53M0.00%−244,700−62.0%Reduced
DLD Asset Management, LP150,000$1.53M0.20%−150,000−50.0%Reduced
Shaolin Capital Management LLC200,000$2.04M0.10%00.0%Unchanged
UBS Oconnor LLC200,000$2.05M0.06%00.0%Unchanged
Schonfeld Strategic Advisors LLC221,665$2.27M0.02%−98,335−30.7%Reduced
Berkley W R Corp228,206$2.33M0.15%00.0%Unchanged
Aristeia Capital LLC250,000$2.55M0.08%00.0%Unchanged
Whitebox Advisors LLC250,000$2.55M0.05%00.0%Unchanged
Verition Fund Management LLC251,470$2.57M0.01%−50.0%Reduced
Centiva Capital, LP285,515$2.92M0.27%00.0%Unchanged
Mint Tower Capital Management B.V.300,000$3.06M0.39%00.0%Unchanged
Millennium Management LLC303,965$3.10M0.00%+303,965New
Goldman Sachs Group Inc323,854$3.31M0.00%00.0%Unchanged
Mizuho Securities USA LLC335,098$3.39M0.07%−119,902−26.4%Reduced
Rivernorth Capital Management, LLC357,750$3.65M0.21%+357,750New
Commonwealth of Pennsylvania Public School Empls Retrmt Sys400,000$4.09M0.02%00.0%Unchanged
Moore Capital Management, LP450,000$4.59M0.09%00.0%Unchanged
Wolverine Asset Management LLC456,326$4.66M0.07%+441,185+2,913.8%Added
Jain Global LLC500,000$5.12M0.07%00.0%Unchanged
Periscope Capital Inc.500,000$5.12M1.24%+50,000+11.1%Added
Picton Mahoney Asset Management500,000$5.12M0.07%00.0%Unchanged
Driehaus Capital Management LLC573,083$5.85M0.04%−91,215−13.7%Reduced
Radcliffe Capital Management, L.P.611,522$6.26M0.39%+284,602+87.1%Added
Meteora Capital, LLC649,900$6.64M0.70%+257,370+65.6%Added
Hudson Bay Capital Management LP700,000$7.15M0.04%00.0%Unchanged
Two Sigma Investments, LP725,000$7.40M0.01%00.0%Unchanged
Sculptor Capital LP740,000$7.56M0.10%−560,000−43.1%Reduced
Alberta Investment Management Corp750,000$7.67M0.06%00.0%Unchanged
Governors Lane LP750,000$7.68M1.06%00.0%Unchanged
Ghisallo Capital Management LLC800,000$8.19M0.27%00.0%Unchanged
LMR Partners LLP850,000$8.68M0.11%00.0%Unchanged
Glazer Capital, LLC875,087$8.94M0.30%00.0%Unchanged
Westchester Capital Management, LLC900,000$9.19M0.48%+250,000+38.5%Added
CNH Partners LLC964,382$9.85M0.25%−5,000−0.5%Reduced
Linden Advisors LP1,000,000$10.2M0.07%00.0%Unchanged
D. E. Shaw & Co., Inc.1,138,500$11.6M0.01%00.0%Unchanged
Magnetar Financial LLC1,300,000$13.3M0.08%00.0%Unchanged
Tenor Capital Management Co., L.P.1,500,000$15.3M0.20%00.0%Unchanged
Clear Street LLC––––Not filed