Archimedes Tech SPAC Partners III Co.

ARCIU

Exchange: Nasdaq
Industry: Blank Checks
SEC CIK: 0002083910

SEC filings (opens in a new tab)

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 classesARCI ARCIW

Q1 2026 vs. Q4 2025

How the institutions holding Archimedes Tech SPAC Partners III Co. changed between Q4 2025 and Q1 2026.

All holders in Q1 2026 All holders in Q4 2025

13F holders of ARCIU: Q4 2025 compared with Q1 2026
Measure	Q4 2025	Q1 2026	Change
Holders	0	29	+29
Shares	0	9.10M	+9.10M
Value	$0	$91.0M	+$91.0M

New holders (29)

Institutions that held Archimedes Tech SPAC Partners III Co. at the end of Q1 2026 but not at the end of Q4 2025.

Institutions new to ARCIU in Q1 2026
Institution	Shares	Value	% of portfolio
LMR Partners LLP	1,250,000	$12.5M	0.12%
Alberta Investment Management Corp	1,000,000	$10.0M	0.06%
CNH Partners LLC	757,625	$7.56M	0.12%
Tudor Investment Corp Et Al	650,000	$6.50M	0.03%
Rivernorth Capital Management, LLC	500,000	$5.00M	0.25%
Lighthouse Investment Partners, LLC	500,000	$5.00M	0.19%
BNP Paribas Arbitrage, SA	492,375	$4.92M	0.00%
Omers Administration Corp	480,000	$4.80M	0.03%
Commonwealth of Pennsylvania Public School Empls Retrmt Sys	400,000	$4.00M	0.02%
Aristeia Capital LLC	399,790	$4.00M	0.09%
Millennium Management LLC	350,000	$3.50M	0.00%
MMCAP International Inc. SPC	300,000	$3.00M	0.26%
BlueCrest Capital Management Ltd	275,000	$2.76M	0.26%
Lineage Point Capital LP	275,000	$2.75M	0.67%
Toronto Dominion Bank	250,000	$2.50M	0.00%
Schonfeld Strategic Advisors LLC	236,368	$2.36M	0.02%
Wealthspring Capital LLC	166,480	$1.66M	0.40%
Qube Research & Technologies Ltd	150,000	$1.50M	0.00%
Picton Mahoney Asset Management	150,000	$1.50M	0.02%
Calamos Advisors LLC	124,000	$1.24M	0.00%
Boothbay Fund Management, LLC	100,000	$1.00M	0.02%
Westchester Capital Management, LLC	100,000	$998.0K	0.05%
Bulldog Investors, LLP	67,500	$674.3K	0.15%
Abc Arbitrage SA	40,000	$400.0K	0.05%
HRT Financial LP	24,996	$250.0K	0.00%
Prelude Capital Management, LLC	20,000	$200.0K	0.02%
Stoic Point Capital Management LLC	20,000	$200.0K	0.20%
Clear Street Group Inc.	10,062	$100.6K	0.00%
Tuttle Tactical Management	10,000	$99.8K	0.16%

Sold out (0)

Institutions that held Archimedes Tech SPAC Partners III Co. at the end of Q4 2025 and filed for Q1 2026 without it.

None.