ARCI · Archimedes Tech SPAC Partners III Co.

$10.10 -0.01 (-0.10%) At close · Sep 4

Market Cap

$356.15M

35.26M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Use institutional holdings through the 13F API or MCP →

Quarter:

Holders: 64

Total Value: $247,976,252

Total Shares: 29,423,032

Showing 1–100 of 103 holdings by value · page 1 of 2

Institutional Ownership Trend

2 quarters

Holder Concentration

Across 64 13F filers · Δ vs Mar 31, 2026

Top Holder

7.3%

+0.0 pts

Top 5

26.7%

+0.6 pts

Top 10

44.7%

+1.1 pts

HHI

302

Broadly held+12

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: -3

Institutional value: +1.5%

Shares held: +3.6%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Large TORONTO DOMINION BANK	+476,735	822,133
Mid Alberta Investment Management Corp	+250,000	1,250,000
Mid AQR Arbitrage LLC	+189,390	947,015
Mid Governors Lane LP	+146,610	1,396,610
Mid RIVERNORTH CAPITAL MANAGEMENT, LLC	+125,000	625,000

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Large ADAGE CAPITAL PARTNERS GP, L.L.C.	−175,000	2,000,000
Small Alpine Global Management, LLC	−147,300	40,200
Small METEORA CAPITAL, LLC	−98,986	508,474
Large Clear Street Group Inc.	−72,053	237,072
Mid GLAZER CAPITAL, LLC	−66,084	557,332

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Mid MANGROVE PARTNERS IM, LLC	200,000	$2,002,000
Mid Centiva Capital, LP	394,489	$701,200
Mid Arax Advisory Partners	1,875	$15,015
Mega UBS Group AG	57	$0

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)
Mid Lighthouse Investment Partners, LLC	500,000	$5,000,000
Large Calamos Advisors LLC	124,000	$1,240,000
Mid Virtu Financial LLC	109,734	$893,729
Small DELTEC ASSET MANAGEMENT LLC	35,000	$344,750
Mid PRELUDE CAPITAL MANAGEMENT, LLC	20,000	$200,000

Filter: New 4 Increased 23 Reduced 12 Sold out 7 Unchanged 25

Showing 100 of 103

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

ADAGE CAPITAL PARTNERS GP, L.L.C.

$18,018,000

7.27%

1,800,000

LMR Partners LLP ARCIU

$12,737,500

5.14%

1,250,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
LMR PARTNERS (DIFC) Ltd	1,250,000	$12,737,500	100.0%	Sole

Linden Advisors LP

$12,012,000

4.84%

1,200,000

Magnetar Financial LLC

$12,012,000

4.84%

1,200,000

Governors Lane LP

$11,477,566

4.63%

1,146,610

Alberta Investment Management Corp

$10,010,000

4.04%

1,000,000

TENOR CAPITAL MANAGEMENT Co., L.P.

$10,010,000

4.04%

1,000,000

Verition Fund Management LLC

$8,161,703

3.29%

815,355

SONA ASSET MANAGEMENT (US) LLC

$8,008,000

3.23%

800,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SONA ASSET MANAGEMENT (UK) LLP	800,000	$8,008,000	100.0%	Other

AQR Arbitrage LLC

$7,583,696

3.06%

757,612

TUDOR INVESTMENT CORP ET AL ARCIU

$6,623,500

2.67%

650,000

TORONTO DOMINION BANK ARCIU

$6,584,951

2.66%

646,217

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
TD SECURITIES (USA) LLC	573,517	$5,844,138	88.7%	Defined
Held directly	72,700	$740,813	11.3%	Sole

HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND

$5,505,500

2.22%

550,000

Shaolin Capital Management LLC

$5,108,963

2.06%

510,386

Radcliffe Capital Management, L.P.

$5,051,776

2.04%

504,673

Polar Asset Management Partners Inc.

$5,005,000

2.02%

500,000

RIVERNORTH CAPITAL MANAGEMENT, LLC

$5,005,000

2.02%

500,000

MOORE CAPITAL MANAGEMENT, LP

$5,005,000

2.02%

500,000

GLAZER CAPITAL, LLC

$4,973,058

2.01%

496,809

BNP PARIBAS ARBITRAGE, SA

$4,928,643

1.99%

492,372

OMERS ADMINISTRATION Corp ARCIU

$4,891,200

1.97%

480,000

D. E. Shaw & Co., Inc.

$4,509,505

1.82%

450,500

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
D. E. SHAW & CO, L.P.	450,500	$4,509,505	100.0%	Defined

METEORA CAPITAL, LLC

$4,249,134

1.71%

424,489

Periscope Capital Inc.

$4,094,100

1.65%

409,001

ARISTEIA CAPITAL, L.L.C. ARCIU

$4,083,938

1.65%

400,779

COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS

$4,004,000

1.61%

400,000

K2 PRINCIPAL FUND, L.P.

$3,086,413

1.24%

308,333

Hudson Bay Capital Management LP

$3,003,000

1.21%

300,000

MMCAP International Inc. SPC

$3,003,000

1.21%

300,000

Schonfeld Strategic Advisors LLC

$2,977,014

1.20%

297,404

Lineage Point Capital LP ARCIU

$2,942,627

1.19%

288,776

BlueCrest Capital Management Ltd ARCIU

$2,802,250

1.13%

275,000

TWO SIGMA INVESTMENTS, LP

$2,740,647

1.11%

273,791

HBK INVESTMENTS L P

$2,502,540

1.01%

250,004

Ghisallo Capital Management LLC

$2,502,500

1.01%

250,000

BERKLEY W R CORP

$2,482,480

1.00%

248,000

First Trust Capital Management L.P.

$2,002,000

0.81%

200,000

MANGROVE PARTNERS IM, LLC

$2,002,000

0.81%

200,000

683 Capital Management, LLC

$2,002,000

0.81%

200,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
683 Capital Partners, LP	200,000	$2,002,000	100.0%	Defined

MILLENNIUM MANAGEMENT LLC ARCIU

$1,831,581

0.74%

179,743

TORONTO DOMINION BANK

$1,760,919

0.71%

175,916

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
TD SECURITIES (USA) LLC	26,616	$266,426	15.1%	Defined
Held directly	149,300	$1,494,493	84.9%	Sole

DLD Asset Management, LP

$1,701,700

0.69%

170,000

Wealthspring Capital LLC

$1,611,209

0.65%

160,960

Qube Research & Technologies Ltd ARCIU

$1,528,500

0.62%

150,000

StoneX Group Inc.

$1,504,593

0.61%

150,309

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STONEX FINANCIAL INC.	150,309	$1,504,593	100.0%	Defined

Mint Tower Capital Management B.V.

$1,501,500

0.61%

150,000

MILLENNIUM MANAGEMENT LLC

$1,501,500

0.61%

150,000

PICTON MAHONEY ASSET MANAGEMENT

$1,501,459

0.61%

149,996

Clear Street Group Inc.

$1,477,576

0.60%

147,610

Westchester Capital Management, LLC ARCIU

$1,018,999

0.41%

100,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WESTCHESTER CAPITAL PARTNERS, LLC	887	$9,038	0.9%	Sole
Virtus Investment Advisers, LLC	90,634	$923,560	90.6%	Other
Held directly	8,479	$86,401	8.5%	Sole

WHITEBOX ADVISORS LLC

$1,001,000

0.40%

100,000

Context Capital Management, LLC

$1,001,000

0.40%

100,000

BOOTHBAY FUND MANAGEMENT, LLC

$950,950

0.38%

95,000

JPMORGAN CHASE & CO

$877,516

0.35%

87,664

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
JPMorgan Chase Bank, N.A.	87,664	$877,516	100.0%	Defined

L1 Global Manager Pty Ltd

$750,750

0.30%

75,000

Centiva Capital, LP

$701,200

0.28%

70,050

Bulldog Investors, LLP

$645,645

0.26%

64,500

ABC ARBITRAGE SA

$350,350

0.14%

35,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
ABC ARBITRAGE ASSET MANAGEMENT	35,000	$350,350	100.0%	Other

Clear Street Group Inc. ARCIU

$349,068

0.14%

34,256

WOLVERINE ASSET MANAGEMENT LLC

$329,799

0.13%

32,947

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Wolverine Holdings, LLC	32,947	$329,799	100.0%	Defined

HRT FINANCIAL LP ARCIU

$254,750

0.10%

25,000

GLAZER CAPITAL, LLC ARCIU

$107,229

0.04%

10,523

Arax Advisory Partners

$15,015

0.01%

1,500

MORGAN STANLEY

$240

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY CAPITAL SERVICES, LLC	24	$240	100.0%	Defined

MOORE CAPITAL MANAGEMENT, LP ARCIW

—

125,000

BNP PARIBAS ARBITRAGE, SA ARCIW

—

123,093

Parallax Volatility Advisers, L.P. ARCIW

—

50,000

Polar Asset Management Partners Inc. ARCIW

—

129,300

HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND ARCIW

—

137,500

GLAZER CAPITAL, LLC ARCIW

—

50,000

PICTON MAHONEY ASSET MANAGEMENT ARCIW

—

37,499

Magnetar Financial LLC ARCIW

—

300,000

Bulldog Investors, LLP ARCIW

—

15,000

K2 PRINCIPAL FUND, L.P. ARCIW

—

308,837

Clear Street Group Inc. ARCIW

—

55,206

ROYAL BANK OF CANADA ARCIW

—

375

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
RBC CMA LTD.	375	$0	—	Defined

Arax Advisory Partners ARCIW

—

375

DLD Asset Management, LP ARCIW

—

42,499

Alpine Global Management, LLC ARCIW

—

40,200

Alberta Investment Management Corp ARCIW

—

250,000

TENOR CAPITAL MANAGEMENT Co., L.P. ARCIW

—

250,000

AQR Arbitrage LLC ARCIW

—

189,403

METEORA CAPITAL, LLC ARCIW

—

83,985

Mint Tower Capital Management B.V. ARCIW

—

37,500

SONA ASSET MANAGEMENT (US) LLC ARCIW

—

200,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
SONA ASSET MANAGEMENT (UK) LLP	200,000	$0	—	Other

HBK INVESTMENTS L P ARCIW

—

62,501

Governors Lane LP ARCIW

—

250,000

D. E. Shaw & Co., Inc. ARCIW

—

106,250

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
D. E. SHAW & CO, L.P.	106,250	$0	—	Defined

WHITEBOX ADVISORS LLC ARCIW

—

25,000

Shaolin Capital Management LLC ARCIW

—

114,720

BOOTHBAY FUND MANAGEMENT, LLC ARCIW

—

25,000

UBS Group AG ARCIW

—

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS Securities LLC	57	$0	—	Defined

Verition Fund Management LLC ARCIW

—

187,200

MMCAP International Inc. SPC ARCIW

—

75,000

Radcliffe Capital Management, L.P. ARCIW

—

81,385

Centiva Capital, LP ARCIW

—

324,439

683 Capital Management, LLC ARCIW

—

50,000

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
683 Capital Partners, LP	50,000	$0	—	Defined

Schonfeld Strategic Advisors LLC ARCIW

—

40,000

RIVERNORTH CAPITAL MANAGEMENT, LLC ARCIW

—

125,000

ADAGE CAPITAL PARTNERS GP, L.L.C. ARCIW

—

200,000

Key facts CIK 2083910 CUSIP G0453R105 13F (30d) 45 filings 45 filers Visit website