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

4,659,293

selection includes debt or preferreds — no % of shares outstanding

Holders

+12 vs 2026-03-31 · 15 new, 3 exited

Value

$3.5M

shares +30.7% 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 (41 of 41 · G0453R113)

change vs 2026-03-31

#	Filer	Shares / principal	% of class	Value	Change
1	Centiva Capital, LP	324,439	—	$243K	NEW
2	K2 PRINCIPAL FUND, L.P.	308,837	—	$154K	+27,060 (+9.6%)
3	Magnetar Financial LLC	300,000	—	$225K	—
4	Linden Advisors LP	299,999	—	$188K	—
5	Governors Lane LP	250,000	—	$156K	—
6	TENOR CAPITAL MANAGEMENT Co., L.P.	250,000	—	$188K	—
7	Alberta Investment Management Corp	250,000	—	$188K	NEW
8	ADAGE CAPITAL PARTNERS GP, L.L.C.	200,000	—	$150K	-175,000 (-46.7%)
9	SONA ASSET MANAGEMENT (US) LLC	200,000	—	$150K	—
10	AQR Arbitrage LLC	189,403	—	$142K	NEW
11	Verition Fund Management LLC	187,200	—	$140K	-300 (-0.2%)
12	HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND	137,500	—	$103K	—
13	Polar Asset Management Partners Inc.	129,300	—	$97K	+4,300 (+3.4%)
14	RIVERNORTH CAPITAL MANAGEMENT, LLC	125,000	—	$81K	NEW
15	MOORE CAPITAL MANAGEMENT, LP	125,000	—	$94K	—
16	BNP PARIBAS FINANCIAL MARKETS	123,093	—	$77K	NEW
17	Shaolin Capital Management LLC	114,720	—	$86K	+4,609 (+4.2%)
18	D. E. Shaw & Co., Inc.	106,250	—	$80K	—
19	Periscope Capital Inc.	101,100	—	$63K	—
20	COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS	100,000	—	$63K	NEW
21	Meteora Capital, LLC	83,985	—	$42K	-39,735 (-32.1%)
22	Radcliffe Capital Management, L.P.	81,385	—	$51K	+43 (+0.1%)
23	MMCAP International Inc. SPC	75,000	—	$56K	NEW
24	HBK INVESTMENTS L P	62,501	—	$47K	—
25	Clear Street Group Inc.	55,206	—	$41K	-3,094 (-5.3%)
26	683 Capital Management, LLC	50,000	—	$38K	—
27	GLAZER CAPITAL, LLC	50,000	—	$31K	-68,814 (-57.9%)
28	Parallax Volatility Advisers, L.P.	50,000	—	$38K	NEW
29	DLD Asset Management, LP	42,499	—	$32K	—
30	Wealthspring Capital LLC	40,870	—	$20K	NEW
31	Alpine Global Management, LLC	40,200	—	$20K	+2,700 (+7.2%)
32	Schonfeld Strategic Advisors LLC	40,000	—	$25K	NEW
33	Mint Tower Capital Management B.V.	37,500	—	$28K	—
34	PICTON MAHONEY ASSET MANAGEMENT	37,499	—	$28K	NEW
35	BOOTHBAY FUND MANAGEMENT, LLC	25,000	—	$250K	NEW
36	Context Capital Management, LLC	25,000	—	$16K	—
37	WHITEBOX ADVISORS LLC	25,000	—	$19K	—
38	Bulldog Investors, LLP	15,000	—	$11K	NEW
39	ROYAL BANK OF CANADA	375	—	$0	-300 (-44.4%)
40	Arax Advisory Partners	375	—	$188	NEW
41	UBS Group AG	57	—	$29	NEW

Exited since 2026-03-31 (3 filers; largest 3 shown)

Virtu Financial LLC	−19,000
L1 Global Manager Pty Ltd	−18,750
Hudson Bay Capital Management LP	−15,001

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.