Who owns ARCIWhat ARCI owns — n/a

Who owns Archimedes Tech SPAC Partners III Co.?

Prices and market caps: Cboe delayed data, at least 15 minutes delayed. Not real-time. Fundamentals from company filings.

Institutional ownership of ARCI from SEC Form 13F filings across 52 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.

As of the 2026-06-30 reporting period, 52 institutions disclosed 20.2M shares of Archimedes Tech SPAC Partners III Co. worth $202.6M — about 57.4% of shares outstanding; the largest disclosed holder is ADAGE CAPITAL PARTNERS GP, L.L.C.. Source: SEC Form 13F filings, parsed by EvidInvest.

13F holders

$202.6M

value, 2026 filers

57.4%

of shares outstanding (20.2M sh)

new positions (2026 filers)

Top institutional holders

ordered by shares owned · positions as of 2026-06-30 · % of fund = share of the manager's own book · % of co. = share of ARCI's shares outstanding

#	Manager	Shares	Value	% of fund	% of co.	Δ shares QoQ
1	ADAGE CAPITAL PARTNERS GP, L.L.C.	1.8M	$18.0M	0.0%	5.1%	0.0%
2	Linden Advisors LP	1.2M	$12.0M	0.1%	3.4%	0.0%
3	Magnetar Financial LLC	1.2M	$12.0M	0.1%	3.4%	0.0%
4	Governors Lane LP	1.1M	$11.5M	1.0%	3.3%	+14.7%
5	TENOR CAPITAL MANAGEMENT Co., L.P.	1.0M	$10.0M	0.1%	2.8%	0.0%
6	Alberta Investment Management CorpNEW	1.0M	$10.0M	0.1%	2.8%	new
7	Verition Fund Management LLC	815,355	$8.2M	0.0%	2.3%	+8.7%
8	SONA ASSET MANAGEMENT (US) LLC	800,000	$8.0M	0.2%	2.3%	0.0%
9	AQR Arbitrage LLCNEW	757,612	$7.6M	0.1%	2.1%	new
10	HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND	550,000	$5.5M	0.0%	1.6%	0.0%
11	Shaolin Capital Management LLC	510,386	$5.1M	0.2%	1.4%	-5.6%
12	Radcliffe Capital Management, L.P.	504,673	$5.1M	0.4%	1.4%	+21.8%
13	MOORE CAPITAL MANAGEMENT, LP	500,000	$5.0M	0.1%	1.4%	0.0%
14	Polar Asset Management Partners Inc.	500,000	$5.0M	0.1%	1.4%	0.0%
15	RIVERNORTH CAPITAL MANAGEMENT, LLCNEW	500,000	$5.1M	0.2%	1.4%	new
16	GLAZER CAPITAL, LLC	496,809	$5.0M	0.1%	1.4%	-1.5%
17	BNP PARIBAS FINANCIAL MARKETSNEW	492,372	$4.9M	0.0%	1.4%	new
18	D. E. Shaw & Co., Inc.	450,500	$4.5M	0.0%	1.3%	+6.0%
19	Meteora Capital, LLC	424,489	$4.2M	0.4%	1.2%	-12.2%
20	Periscope Capital Inc.	409,001	$4.1M	0.4%	1.2%	0.0%
21	COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYSNEW	400,000	$4.0M	0.0%	1.1%	new
22	K2 PRINCIPAL FUND, L.P.	308,333	$3.1M	0.2%	0.9%	+2.9%
23	Hudson Bay Capital Management LP	300,000	$3.0M	0.0%	0.9%	0.0%
24	MMCAP International Inc. SPCNEW	300,000	$3.0M	0.3%	0.9%	new
25	Schonfeld Strategic Advisors LLCNEW	297,404	$3.0M	0.0%	0.8%	new

Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.