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Archimedes Tech SPAC Partners III Co.

ARCIU
Exchange
Nasdaq
Industry
Blank Checks
SEC CIK
0002083910

No open-market purchases or sales by Archimedes Tech SPAC Partners III Co. insiders were filed in the last 90 days; 15 institutions reported holding it in 13F filings for Q2 2026, worth $47.3M in total; no superinvestor holds it.

Other share classesARCIARCIW

13F holders, Q1 2026

Institutional positions in Archimedes Tech SPAC Partners III Co. as of Mar 31, 2026. 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
29
+29 vs. Q4 2025
Shares held
9.10M
+9.10M vs. Q4 2025
Total value
$91.0M
+$91.0M vs. Q4 2025
New holders
29
0 more added
Sold out
0
0 more reduced

Compare with Q4 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting ARCIU 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 holdersQ1 2026: 29 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: 0 institutionsQ3 2025: 0 institutionsQ4 2025: 0 institutionsQ1 2026: 29 institutionsQ2 2026: 15 institutions
Value heldQ1 2026: $91.0M
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: $0Q3 2025: $0Q4 2025: $0Q1 2026: $91.0MQ2 2026: $47.3M
Institutions holding ARCIU and their total value by quarter
QuarterHoldersValue
Q2 202615$47.3M
Q1 202629$91.0M
Q4 20250$0
Q3 20250$0
Q2 20250$0
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, Q1 2026

Shares, value and share of portfolio for each institution holding Archimedes Tech SPAC Partners III Co.; share changes are against Q4 2025.

Institutions holding ARCIU in Q1 2026
InstitutionSharesValue% of portfolioChange in sharesAction
LMR Partners LLP1,250,000$12.5M0.12%+1,250,000New
Alberta Investment Management Corp1,000,000$10.0M0.06%+1,000,000New
CNH Partners LLC757,625$7.56M0.12%+757,625New
Tudor Investment Corp Et Al650,000$6.50M0.03%+650,000New
Rivernorth Capital Management, LLC500,000$5.00M0.25%+500,000New
Lighthouse Investment Partners, LLC500,000$5.00M0.19%+500,000New
BNP Paribas Arbitrage, SA492,375$4.92M0.00%+492,375New
Omers Administration Corp480,000$4.80M0.03%+480,000New
Commonwealth of Pennsylvania Public School Empls Retrmt Sys400,000$4.00M0.02%+400,000New
Aristeia Capital LLC399,790$4.00M0.09%+399,790New
Millennium Management LLC350,000$3.50M0.00%+350,000New
MMCAP International Inc. SPC300,000$3.00M0.26%+300,000New
BlueCrest Capital Management Ltd275,000$2.76M0.26%+275,000New
Lineage Point Capital LP275,000$2.75M0.67%+275,000New
Toronto Dominion Bank250,000$2.50M0.00%+250,000New
Schonfeld Strategic Advisors LLC236,368$2.36M0.02%+236,368New
Wealthspring Capital LLC166,480$1.66M0.40%+166,480New
Qube Research & Technologies Ltd150,000$1.50M0.00%+150,000New
Picton Mahoney Asset Management150,000$1.50M0.02%+150,000New
Calamos Advisors LLC124,000$1.24M0.00%+124,000New
Boothbay Fund Management, LLC100,000$1.00M0.02%+100,000New
Westchester Capital Management, LLC100,000$998.0K0.05%+100,000New
Bulldog Investors, LLP67,500$674.3K0.15%+67,500New
Abc Arbitrage SA40,000$400.0K0.05%+40,000New
HRT Financial LP24,996$250.0K0.00%+24,996New
Prelude Capital Management, LLC20,000$200.0K0.02%+20,000New
Stoic Point Capital Management LLC20,000$200.0K0.20%+20,000New
Clear Street Group Inc.10,062$100.6K0.00%+10,062New
Tuttle Tactical Management10,000$99.8K0.16%+10,000New