Institutional HoldersBeta

Who holds a company, from every 13F filed for the quarter, one row per filer exactly as filed, against the latest share count the company reported.

Archimedes Tech SPAC Partners III Co.

CIK 0002083910ARCIARCIUARCIW· quarter ending 2026-06-30

Shares outstanding

35,262,000

as of 2026-08-12 · 10-Q cover page, filed 2026-08-13

Held by 13F filers

20,236,815

57.4% of shares outstanding

Holders

+12 vs 2026-03-31 · 16 new, 4 exited

Value

$202.6M

shares +30.0% vs prior quarter

Share classes (cover page of the 10-Q filed 2026-08-13, as of 2026-08-12)

Class	Listed	Shares outstanding	Held by 13F filers	% of class	Holders	CUSIP
Common stock	ARCI · NASDAQ	35,262,000	20,236,815	57.4%	52	G0453R105

Each class is compared with its own share count; classes are not added together. A class that is not exchange-listed cannot be held by 13F filers.

Securities (CUSIPs held in 13F this quarter)

tick to combine

CUSIP	Class (as filers write it)	Holders	Shares held	Class shares	% of class	Value	Options	Mapped via
G0453R105	ORD SHS	52	20,236,815	35,262,000	57.4%	$202.6M	—	13DG	holders →
G0453R121	UNIT 01/23/2031not common	15	4,625,063	—	—	$47.3M	—	NPORT	holders →
G0453R113	*W EXP 01/23/203not common	41	4,659,293	—	—	$3.5M	1 call / 0 put	NPORT	holders →

Totals combine the ticked CUSIPs and update as you tick: common-stock classes by default; preferreds, notes, warrants and depositary shares are listed but not counted. "holders →" shows a single CUSIP on its own. Bonds are held as a principal amount, not shares. Options positions are never counted as holdings.

Top holders (52 of 52 · G0453R105)

change vs 2026-03-31

#	Filer	Shares	% of class	Value	Change
1	ADAGE CAPITAL PARTNERS GP, L.L.C.	1,800,000	5.10%	$18.0M	—
2	Linden Advisors LP	1,200,000	3.40%	$12.0M	—
3	Magnetar Financial LLC	1,200,000	3.40%	$12.0M	—
4	Governors Lane LP	1,146,610	3.25%	$11.5M	+146,610 (+14.7%)
5	Alberta Investment Management Corp	1,000,000	2.84%	$10.0M	NEW
6	TENOR CAPITAL MANAGEMENT Co., L.P.	1,000,000	2.84%	$10.0M	—
7	Verition Fund Management LLC	815,355	2.31%	$8.2M	+65,355 (+8.7%)
8	SONA ASSET MANAGEMENT (US) LLC	800,000	2.27%	$8.0M	—
9	AQR Arbitrage LLC	757,612	2.15%	$7.6M	NEW
10	HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND	550,000	1.56%	$5.5M	—
11	Shaolin Capital Management LLC	510,386	1.45%	$5.1M	-30,068 (-5.6%)
12	Radcliffe Capital Management, L.P.	504,673	1.43%	$5.1M	+90,376 (+21.8%)
13	MOORE CAPITAL MANAGEMENT, LP	500,000	1.42%	$5.0M	—
14	Polar Asset Management Partners Inc.	500,000	1.42%	$5.0M	—
15	RIVERNORTH CAPITAL MANAGEMENT, LLC	500,000	1.42%	$5.1M	NEW
16	GLAZER CAPITAL, LLC	496,809	1.41%	$5.0M	-7,793 (-1.5%)
17	BNP PARIBAS FINANCIAL MARKETS	492,372	1.40%	$4.9M	NEW
18	D. E. Shaw & Co., Inc.	450,500	1.28%	$4.5M	+25,500 (+6.0%)
19	Meteora Capital, LLC	424,489	1.20%	$4.2M	-59,251 (-12.2%)
20	Periscope Capital Inc.	409,001	1.16%	$4.1M	—
21	COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS	400,000	1.13%	$4.0M	NEW
22	K2 PRINCIPAL FUND, L.P.	308,333	0.87%	$3.1M	+8,797 (+2.9%)
23	Hudson Bay Capital Management LP	300,000	0.85%	$3.0M	—
24	MMCAP International Inc. SPC	300,000	0.85%	$3.0M	NEW
25	Schonfeld Strategic Advisors LLC	297,404	0.84%	$3.0M	NEW
26	TWO SIGMA INVESTMENTS, LP	273,791	0.78%	$2.7M	—
27	HBK INVESTMENTS L P	250,004	0.71%	$2.5M	—
28	Ghisallo Capital Management LLC	250,000	0.71%	$2.5M	—
29	BERKLEY W R CORP	248,000	0.70%	$2.5M	—
30	First Trust Capital Management L.P.	200,000	0.57%	$2.0M	—
31	683 Capital Management, LLC	200,000	0.57%	$2.0M	—
32	MANGROVE PARTNERS IM, LLC	200,000	0.57%	$2.0M	NEW
33	TORONTO DOMINION BANK	175,916	0.50%	$1.8M	+80,518 (+84.4%)
34	DLD Asset Management, LP	170,000	0.48%	$1.7M	—
35	Wealthspring Capital LLC	160,960	0.46%	$1.6M	NEW
36	StoneX Group Inc.	150,309	0.43%	$1.5M	+40,564 (+37.0%)
37	Mint Tower Capital Management B.V.	150,000	0.43%	$1.5M	—
38	MILLENNIUM MANAGEMENT LLC	150,000	0.43%	$1.5M	NEW
39	PICTON MAHONEY ASSET MANAGEMENT	149,996	0.43%	$1.5M	NEW
40	Clear Street Group Inc.	147,610	0.42%	$1.5M	-93,153 (-38.7%)
41	WHITEBOX ADVISORS LLC	100,000	0.28%	$1.0M	—
42	Context Capital Management, LLC	100,000	0.28%	$1.0M	—
43	BOOTHBAY FUND MANAGEMENT, LLC	95,000	0.27%	$951K	NEW
44	JPMORGAN CHASE & CO	87,664	0.25%	$877K	—
45	L1 Global Manager Pty Ltd	75,000	0.21%	$751K	—
46	Centiva Capital, LP	70,050	0.20%	$701K	NEW
47	Bulldog Investors, LLP	64,500	0.18%	$646K	NEW
48	DELTEC ASSET MANAGEMENT LLC	35,000	0.10%	$350K	—
49	ABC ARBITRAGE SA	35,000	0.10%	$350K	NEW
50	WOLVERINE ASSET MANAGEMENT LLC	32,947	0.09%	$330K	+22,860 (+226.6%)
51	Arax Advisory Partners	1,500	0.00%	$15K	NEW
52	MORGAN STANLEY	24	0.00%	$240	+7 (+41.2%)

Exited since 2026-03-31 (4 filers; largest 4 shown)

Alpine Global Management, LLC	−150,000
Virtu Financial LLC	−90,734
Parallax Volatility Advisers, L.P.	−50,000
ROYAL BANK OF CANADA	−2,700

Large holders from 13D/13G (latest per reporting person, last 2 years)

Filed when a holder crosses 5% or changes materially, so often more current than the quarter-end 13F. Percentages are the filer's own, against the share count they used.

Reporting person	Form	Filed	Event	Shares	% of class
Adage Capital Management, L.P.	SCHEDULE 13G	2026-05-13	2026-03-31	1,800,000	5.1%
Phillip Gross	SCHEDULE 13G	2026-05-13	2026-03-31	1,800,000	5.1%
Robert Atchinson	SCHEDULE 13G	2026-05-13	2026-03-31	1,800,000	5.1%

Source: SEC Form 13F-HR information tables for the quarter ending 2026-06-30 (filed within 45 days of quarter end; amendments applied; values normalised to dollars), the share count from the company's latest 10-K/10-Q XBRL cover page, and Schedule 13D/13G filings. Each row is a legal 13F filer as filed — related entities (e.g. Vanguard's advisers) are not merged. Retail brokerage accounts are not reported on 13F, so the remainder is mostly retail and insiders.