GROUP ONE TRADING LLC

Position in NPKI — NPK International Inc.

CIK 932540 CHICAGO, IL

Position in NPKI

as of Mar 31, 2026 · filed May 13, 2026 Compact

Position Value

$14,388

-$27,141 QoQ

Shares Held

993

-71.5% QoQ

Ownership

0.001%

of shares outstanding

% of Portfolio

0.00%

of 13F equity value

Holder Rank

—

not a current holder

Holding Since

Mar 2020

11 quarters on record

Voting authority Sole 100.ToString("F0")% Shared 0.ToString("F0")% None 0.ToString("F0")%

Industrials · as of Mar 31, 2026

GROUP ONE TRADING LLC holds $5,231,443 across 11 Building Products & Equipment names. NPKI ranks #8 (0.3% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	CARR	CARRIER GLOBAL Corp	41,801	$2,353,814
2	BLDR	Builders FirstSource, Inc.	24,561	$2,022,107
3	APT	Alpha Pro Tech Ltd	113,071	$502,035
4	MAS	Masco Corp /De/	2,524	$152,373
5	TREX	Trex Co Inc	2,395	$87,225
6	LMB	Limbach Holdings, Inc.	673	$52,527
7	LPX	Louisiana-Pacific Corp	404	$29,391
8	NPKI	NPK International Inc. This page	993	$14,388

11 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-03-31	$14,388	993	-71.5%	Shares	Sole	2026-05-13
2025-12-31	$41,529	3,484	-65.8%	Shares	Sole	2026-02-12
2024-06-30	$84,687	10,191	-28.8%	Shares	Sole	2024-08-14
2023-12-31	$95,018	14,310	+362.7%	Shares	Sole	2024-02-14
2022-12-31	$12,835	3,093	0.0%	Shares	Sole	2023-02-09
2022-09-30	$7,794	3,093	+2521.2%	Shares	Sole	2022-11-09
2022-03-31	$431	118	-92.4%	Shares	Sole	2022-05-12
2020-12-31	$2,989	1,557	0.0%	Shares	Sole	2021-02-10
2020-09-30	$1,634	1,557	0.0%	Shares	Sole	2020-11-12
2020-06-30	$3,472	1,557	0.0%	Shares	Sole	2020-08-13
2020-03-31	$1,401	1,557	—	Shares	Sole	2020-05-13
No filing history on record for this holder in this stock.