Thomas Caulfield

Insider

First SEC filing: June 4, 2026 · Latest: June 4, 2026

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Insider at Companies where this person is a reporting insider.
Insider transactions Every share this person bought or sold, from Form 4 filings.
Derivatives Options and other derivative holdings reported by this person.
Initial holdings The stakes this person held when they first started reporting.

Insider at

Insider transactions

0 buys (P) 0 sells (S) Net: $0 + 32 non-open-market transactions below last 12 months, based on the transactions shown below

Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted

No open-market trades on record; showing all filings.

Date	Ticker	Code	Shares	Price	Value	Owned after	Δ own	A/D	vs now
July 7, 2026	USAR	A	271	—	—	3,226 Direct	+9.17%	Acquired	(price as of 2026-08-20)
June 3, 2026	USAR	A	407	—	—	407 Direct	—	Acquired	(price as of 2026-08-20)
June 3, 2026	USAR	M	2,548	—	—	2,955 Direct	+626.04%	Acquired	(price as of 2026-08-20)
June 3, 2026	USAR	M	2,548	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
June 3, 2026	USAR	A	6,438	—	—	6,438 Direct	—	Acquired	(price as of 2026-08-20)
May 12, 2026	SNDK	G	9,666	—	—	4,834 Indirect	-66.66%	Disposed	(price as of 2026-08-20)
March 19, 2026	USAR	A	2,548	—	—	2,548 Direct	—	Acquired	(price as of 2026-08-20)
March 3, 2026	SNDK	G	14,500	—	—	2,312 Direct	-86.25%	Disposed	(price as of 2026-08-20)
March 3, 2026	SNDK	G	14,500	—	—	14,500 Indirect	—	Acquired	(price as of 2026-08-20)
Nov. 18, 2025	SNDK	A	979	—	—	16,812 Direct	+6.18%	Acquired	(price as of 2026-08-20)
March 3, 2025	SNDK	A	4,148	—	—	15,833 Direct	+35.50%	Acquired	(price as of 2026-08-20)
Feb. 28, 2025	SNDK	A	5,693	—	—	11,685 Direct	+95.01%	Acquired	(price as of 2026-08-20)
Nov. 20, 2024	WDC	A	3,759	—	—	21,737 Direct	+20.91%	Acquired	(price as of 2026-08-20)
Nov. 15, 2023	WDC	A	5,213	—	—	17,978 Direct	+40.84%	Acquired	(price as of 2026-08-20)
Nov. 16, 2022	WDC	A	6,589	—	—	12,765 Direct	+106.69%	Acquired	(price as of 2026-08-20)
Nov. 16, 2021	WDC	A	4,103	—	—	6,176 Direct	+197.93%	Acquired	(price as of 2026-08-20)
July 6, 2021	WDC	A	2,073	—	—	2,073 Direct	—	Acquired	(price as of 2026-08-20)
May 18, 2010	PDFS	A	22,500	—	—	22,500 Direct	—	Acquired	(price as of 2026-08-20)
Dec. 16, 2009	PDFS	D	15,000	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
Dec. 16, 2009	PDFS	A	7,500	—	—	18,215 Direct	+70.00%	Acquired	(price as of 2026-08-20)
July 31, 2009	PDFS	A	20,000	—	—	20,000 Direct	—	Acquired	(price as of 2026-08-20)
Aug. 19, 2008	PDFS	A	3,572	—	—	3,572 Direct	—	Acquired	(price as of 2026-08-20)
Aug. 19, 2008	PDFS	A	7,143	—	—	7,143 Direct	—	Acquired	(price as of 2026-08-20)
Aug. 19, 2008	PDFS	D	15,000	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
Aug. 19, 2008	PDFS	D	30,000	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
Aug. 18, 2008	PDFS	A	3,572	—	—	3,572 Direct	—	Acquired	(price as of 2026-08-20)
Aug. 18, 2008	PDFS	A	7,143	—	—	7,143 Direct	—	Acquired	(price as of 2026-08-20)
Aug. 18, 2008	PDFS	D	15,000	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
Aug. 18, 2008	PDFS	D	30,000	—	—	0 Direct	-100.00%	Disposed	(price as of 2026-08-20)
May 22, 2008	PDFS	A	15,000	—	—	15,000 Direct	—	Acquired	(price as of 2026-08-20)
May 30, 2007	PDFS	A	15,000	—	—	15,000 Direct	—	Acquired	(price as of 2026-08-20)
Sept. 15, 2006	PDFS	A	30,000	—	—	30,000 Direct	—	Acquired	(price as of 2026-08-20)

P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding

Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.

Derivative holdings (Form 4 Table II)

Options, RSUs and convertible securities reported on Form 4 Table II.

Date	Ticker	Security	Underlying	Exercise price	Expiration	Shares	A/D
June 3, 2026	USAR	Restricted Stock Units	Common Stock, par value $0.0001 per share (2,548)	—	—	2,548	Disposed
June 3, 2026	USAR	Restricted Stock Units	Common Stock, par value $0.0001 per share (6,438)	—	—	6,438	Acquired
March 19, 2026	USAR	Restricted Stock Units	Common Stock, par value $0.0001 per share (2,548)	—	—	2,548	Acquired
May 18, 2010	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (22,500)	$4.82	May 18, 2020	22,500	Acquired
Dec. 16, 2009	PDFS	2001 Stock Plan Option (Right to Buy)	Common Stock (15,000)	$5.40	May 21, 2018	15,000	Disposed
July 31, 2009	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (20,000)	$2.30	July 30, 2019	20,000	Acquired
Aug. 19, 2008	PDFS	Restricted Stock Right	Common Stock (3,572)	—	—	3,572	Acquired
Aug. 19, 2008	PDFS	Restricted Stock Right	Common Stock (7,143)	—	—	7,143	Acquired
Aug. 19, 2008	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (15,000)	$10.43	May 29, 2017	15,000	Disposed
Aug. 19, 2008	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (30,000)	$12.98	Aug. 29, 2016	30,000	Disposed
Aug. 18, 2008	PDFS	Restricted Stock Right	Common Stock (3,572)	—	—	3,572	Acquired
Aug. 18, 2008	PDFS	Restricted Stock Right	Common Stock (7,143)	—	—	7,143	Acquired
Aug. 18, 2008	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (15,000)	$10.43	May 29, 2017	15,000	Disposed
Aug. 18, 2008	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (30,000)	$12.98	Aug. 29, 2016	30,000	Disposed
May 22, 2008	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (15,000)	$5.40	May 21, 2018	15,000	Acquired
May 30, 2007	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (15,000)	$10.43	May 29, 2017	15,000	Acquired
Sept. 15, 2006	PDFS	2001 Stock Plan Option (right to buy)	Common Stock (30,000)	$12.98	Sept. 14, 2016	30,000	Acquired

Exercise/conversion price is blank when not applicable (e.g. RSUs).

Initial ownership (Form 3) 3 holdings

Securities held when first becoming an insider, per SEC Form 3.

Date	Ticker	Security	Shares	Ownership
March 19, 2026	USAR	Common Stock, par value $0.0001 per share	52,500	Indirect
March 17, 2026	GFS	Ordinary Shares	262,971	Direct
March 17, 2026	GFS	Restricted Share Units	42,057	Direct