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 II Co.

CIK 0002028516ATIIATIIUATIIW· quarter ending 2026-06-30

Shares outstanding

29,590,000

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

Held by 13F filers

17,695,127

59.8% of shares outstanding

Holders

-3 vs 2026-03-31 · 13 new, 16 exited

Value

$190.7M

shares -20.2% vs prior quarter

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

Class	Listed	Shares outstanding	Held by 13F filers	% of class	Holders	CUSIP
Common stock	ATII · NASDAQ	29,590,000	17,695,127	59.8%	51	G04537109

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
G04537109	COM	51	17,695,127	29,590,000	59.8%	$190.7M	—	13DG	holders →
G04537125	*W EXP 10/15/202not common	33	8,366,999 $109 principal	—	—	$18.1M	1 call / 0 put	NPORT	holders →
G04537117	UNIT 10/15/2029not common	4	110,365	—	—	$1.3M	—	13DG	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 (51 of 51 · G04537109)

change vs 2026-03-31

#	Filer	Shares	% of class	Value	Change
1	TENOR CAPITAL MANAGEMENT Co., L.P.	1,367,830	4.62%	$14.7M	-132,170 (-8.8%)
2	Fort Baker Capital Management LP	1,330,746	4.50%	$14.3M	NEW
3	Magnetar Financial LLC	1,297,302	4.38%	$14.0M	-2,698 (-0.2%)
4	D. E. Shaw & Co., Inc.	1,138,500	3.85%	$12.3M	—
5	Decagon Asset Management LLP	937,829	3.17%	$10.1M	NEW
6	Linden Advisors LP	848,273	2.87%	$9.1M	-151,727 (-15.2%)
7	Ghisallo Capital Management LLC	800,000	2.70%	$8.6M	—
8	TWO SIGMA INVESTMENTS, LP	725,000	2.45%	$7.8M	—
9	Hudson Bay Capital Management LP	700,000	2.37%	$7.5M	—
10	Shay Capital LLC	623,687	2.11%	$6.7M	NEW
11	Governors Lane LP	604,857	2.04%	$6.5M	-154,699 (-20.4%)
12	AQR Arbitrage LLC	590,262	1.99%	$6.4M	-330,410 (-35.9%)
13	Sculptor Capital LP	552,619	1.87%	$6.0M	-48,027 (-8.0%)
14	K2 PRINCIPAL FUND, L.P.	526,227	1.78%	$5.7M	+438,327 (+498.7%)
15	LMR Partners LLP	478,978	1.62%	$5.2M	-371,022 (-43.6%)
16	Radcliffe Capital Management, L.P.	478,061	1.62%	$5.2M	-183,276 (-27.7%)
17	MOORE CAPITAL MANAGEMENT, LP	450,000	1.52%	$4.9M	—
18	Alberta Investment Management Corp	400,000	1.35%	$4.3M	-350,000 (-46.7%)
19	FNY Investment Advisers, LLC	327,200	1.11%	$3.5M	NEW
20	Mint Tower Capital Management B.V.	300,000	1.01%	$3.2M	—
21	CITADEL ADVISORS LLC	250,266	0.85%	$2.7M	+239,889 (+2311.7%)
22	WHITEBOX ADVISORS LLC	250,000	0.84%	$2.7M	—
23	Harraden Circle Investments, LLC	234,661	0.79%	$2.5M	NEW
24	GOLDMAN SACHS GROUP INC	205,090	0.69%	$2.2M	-122,360 (-37.4%)
25	ARISTEIA CAPITAL, L.L.C.	200,000	0.68%	$2.2M	-50,000 (-20.0%)
26	L1 Global Manager Pty Ltd	200,000	0.68%	$2.2M	—
27	DLD Asset Management, LP	195,453	0.66%	$2.1M	+45,453 (+30.3%)
28	Jain Global LLC	185,108	0.63%	$2.0M	-314,892 (-63.0%)
29	SkyView Investment Advisors, LLC	182,495	0.62%	$2.0M	NEW
30	CANTOR FITZGERALD, L. P.	176,566	0.60%	$1.9M	NEW
31	Periscope Capital Inc.	175,000	0.59%	$1.9M	-177,880 (-50.4%)
32	Verition Fund Management LLC	140,797	0.48%	$1.5M	-90,673 (-39.2%)
33	MMCAP International Inc. SPC	125,000	0.42%	$1.3M	—
34	TUDOR INVESTMENT CORP ET AL	123,842	0.42%	$1.3M	NEW
35	TORONTO DOMINION BANK	82,550	0.28%	$890K	-567,450 (-87.3%)
36	Baird Financial Group, Inc.	78,500	0.27%	$846K	—
37	Shaolin Capital Management LLC	76,171	0.26%	$821K	-194,612 (-71.9%)
38	MILLENNIUM MANAGEMENT LLC	69,384	0.23%	$748K	-238,601 (-77.5%)
39	GLAZER CAPITAL, LLC	50,100	0.17%	$540K	-699,900 (-93.3%)
40	Schonfeld Strategic Advisors LLC	50,000	0.17%	$539K	-123,515 (-71.2%)
41	HRT FINANCIAL LP	47,190	0.16%	$508K	NEW
42	Clear Street Group Inc.	25,000	0.08%	$270K	-52,452 (-67.7%)
43	BNP PARIBAS FINANCIAL MARKETS	23,790	0.08%	$256K	-13,954 (-37.0%)
44	MIZUHO SECURITIES USA LLC	19,469	0.07%	$202K	—
45	HIGHBRIDGE CAPITAL MANAGEMENT LLC	17,497	0.06%	$189K	NEW
46	READYSTATE ASSET MANAGEMENT LP	12,528	0.04%	$135K	-136,206 (-91.6%)
47	GEODE CAPITAL MANAGEMENT, LLC	11,102	0.04%	$120K	—
48	EverSource Wealth Advisors, LLC	8,500	0.03%	$92K	NEW
49	UBS Group AG	1,658	0.01%	$18K	NEW
50	MORGAN STANLEY	35	0.00%	$377	-27 (-43.5%)
51	Caitong International Asset Management Co., Ltd	4	0.00%	$43	NEW

Exited since 2026-03-31 (16 filers; largest 16 shown)

Westchester Capital Management, LLC	−907,144
PICTON MAHONEY ASSET MANAGEMENT	−500,000
RIVERNORTH CAPITAL MANAGEMENT, LLC	−427,500
RLH Capital LLC	−400,907
COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS	−400,000
J. Goldman & Co LP	−369,778
METEORA CAPITAL, LLC	−295,612
Centiva Capital, LP	−285,515
Quarry LP	−285,000
BERKLEY W R CORP	−208,065
O'Connor Alternative Investments LLC	−200,000
WOLVERINE ASSET MANAGEMENT LLC	−134,280
GRITSTONE ASSET MANAGEMENT LLC	−99,081
Lineage Point Capital LP	−95,895
CSS LLC/IL	−57,143
Virtu Financial LLC	−53,686

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
Robin Shah	SCHEDULE 13G/A	2026-08-14	2026-06-30	1,367,830	4.6%
Tenor Capital Management Company, L.P.	SCHEDULE 13G/A	2026-08-14	2026-06-30	1,367,830	4.6%
Tenor Opportunity Master Fund, Ltd.	SCHEDULE 13G/A	2026-08-14	2026-06-30	1,367,830	4.6%
Barclays PLC	SCHEDULE 13G/A	2026-02-11	2025-12-31	1,148,590	3.88%
Sculptor Capital Holding Corp	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Capital Holding II LLC	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Capital II LP	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Capital LP	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Capital Management, Inc.	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Master Fund, Ltd.	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
Sculptor Special Funding, LP	SCHEDULE 13G/A	2025-08-14	2025-06-30	1,300,000	4.39%
TENOR CAPITAL MANAGEMENT COMPANY, LP	SCHEDULE 13G	2025-02-19	2025-02-11	1,500,000	5.8%

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.