NPK International Inc.
US ˙ NYSE ˙ US6517185046
DIESES SYMBOL IST NICHT MEHR AKTIV

SecurityNR / NPK International Inc.
InstitutionGroup One Trading, L.p.
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Group One Trading, L.p. ownership in NR / NPK International Inc.

On May 13, 2026 - Group One Trading, L.p. filed a 13F-HR form disclosing ownership of 0 shares of NPK International Inc. (US:NR) valued at $0 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 3,484 shares of NPK International Inc.. This represents a change in shares of -100.00% during the quarter. The current value of the position is $0 USD.

Group One Trading, L.p. has a history of taking positions in derivatives of the underlying security (NR) in the form of stock options. The firm currently holds call options representing 1,200 of underlying shares valued at $14,304 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

NR / NPK International Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-13 2026-03-31 13F NPK INTERNATIONAL COM SHS 651718504 0 -3,484 -100.00 0 -100.00
2026-02-11 2025-12-31 13F NPK INTERNATIONAL COM SHS 651718504 3,484 3,484 42 0.0001
2024-11-14 2024-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -10,191 -100.00 0 -100.00
2024-08-14 2024-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 10,191 10,191 85 0.0003
2024-05-10 2024-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -14,310 -100.00 0 -100.00
2024-02-14 2023-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 14,310 14,310 95 0.0002
2023-05-12 2023-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -3,093 -100.00 0 -100.00
2023-02-09 2022-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 3,093 0 0.00 13 50.00 0.0000
2022-11-09 2022-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 3,093 3,093 8 0.0000
2022-08-11 2022-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -118 -100.00 0 0.0000
2022-05-12 2022-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 118 118 0 0.0000
2021-05-12 2021-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -1,557 -100.00 0 -100.00
2021-02-10 2020-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 1,557 0 0.00 3 50.00 0.0000
2020-11-12 2020-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 1,557 0 0.00 2 -33.33 0.0000
2020-08-13 2020-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 1,557 0 0.00 3 200.00 0.0000
2020-05-13 2020-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 1,557 -300 -16.16 1 -91.67 0.0000
2020-02-10 2019-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 1,857 -82 -4.23 12 -20.00 0.0001
2019-11-12 2019-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 1,939 -3,213 -62.36 15 -60.53 0.0001
2019-08-09 2019-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 5,152 4,952 2,476.00 38 1,800.00 0.0003
2017-05-10 2017-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 200 200 2 0.0000
2016-11-14 2016-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 0 -100 -100.00 0 -100.00
2016-08-12 2016-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 100 -1,500 -93.75 1 -94.44 0.0000
2014-05-07 2014-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 1,600 1,300 433.33 18 350.00 0.0003
2014-01-31 2013-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 300 -900 -75.00 4 -73.33 0.0001
2013-11-15 2013-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 1,200 999 497.01 15 650.00 0.0003
2013-08-02 2013-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 201 201 2 0.0000
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-02-11 2025-12-31 13F NPK INTERNATIONAL COM SHS Call 1,200 -76.47 14 -75.44 n/a n/a n/a
2025-11-12 2025-09-30 13F NPK INTERNATIONAL COM SHS Call 5,100 -74.75 58 -66.67 n/a n/a n/a
2025-08-14 2025-06-30 13F NPK INTERNATIONAL COM SHS Call 20,200 -37.07 172 -8.06 n/a n/a n/a
2025-05-14 2025-03-31 13F NPK INTERNATIONAL COM SHS Call 32,100 187 n/a n/a n/a
2025-05-14 2024-12-31 13F/A NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-14 2024-12-31 13F NEWPARK RES COM PAR $.01NEW Call 0 0 n/a n/a n/a
2024-11-14 2024-09-30 13F NEWPARK RES COM PAR $.01NEW Call 3,000 -40.00 21 -51.22 n/a n/a n/a
2024-08-14 2024-06-30 13F NEWPARK RES COM PAR $.01NEW Call 5,000 -13.79 42 0.00 n/a n/a n/a
2024-05-10 2024-03-31 13F NEWPARK RES COM PAR $.01NEW Call 5,800 5,700.00 42 n/a n/a n/a
2024-02-14 2023-12-31 13F NEWPARK RES COM PAR $.01NEW Call 100 -99.92 1 -100.00 n/a n/a n/a
2023-11-09 2023-09-30 13F NEWPARK RES COM PAR $.01NEW Call 130,000 304.98 898 437.72 n/a n/a n/a
2023-08-09 2023-06-30 13F NEWPARK RES COM PAR $.01NEW Call 32,100 1,906.25 168 2,683.33 n/a n/a n/a
2023-05-12 2023-03-31 13F NEWPARK RES COM PAR $.01NEW Call 1,600 220.00 6 200.00 n/a n/a n/a
2023-02-09 2022-12-31 13F NEWPARK RES COM PAR $.01NEW Call 500 2 n/a n/a n/a
2022-11-09 2022-09-30 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-11 2022-06-30 13F NEWPARK RES COM PAR $.01NEW Call 14,100 1,466.67 44 1,366.67 n/a n/a n/a
2022-05-12 2022-03-31 13F NEWPARK RES COM PAR $.01NEW Call 900 -99.06 3 -98.93 n/a n/a n/a
2022-02-11 2021-12-31 13F NEWPARK RES COM PAR $.01NEW Call 95,700 0.31 281 -10.79 n/a n/a n/a
2021-11-12 2021-09-30 13F NEWPARK RES COM PAR $.01NEW Call 95,400 0.21 315 -4.26 n/a n/a n/a
2021-08-10 2021-06-30 13F NEWPARK RES COM PAR $.01NEW Call 95,200 1.28 329 11.53 n/a n/a n/a
2021-05-12 2021-03-31 13F NEWPARK RES COM PAR $.01NEW Call 94,000 1,780.00 295 2,850.00 n/a n/a n/a
2021-02-10 2020-12-31 13F NEWPARK RES COM PAR $.01NEW Call 5,000 10 n/a n/a n/a
2020-11-12 2020-09-30 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-08-13 2020-06-30 13F NEWPARK RES COM PAR $.01NEW Call 800 -94.67 2 -98.20 n/a n/a n/a
2019-08-09 2019-06-30 13F NEWPARK RES COM PAR $.01NEW Call 15,000 0.00 111 -18.98 n/a n/a n/a
2019-05-14 2019-03-31 13F/A NEWPARK RES COM PAR $.01NEW Call 15,000 137 n/a n/a n/a
2019-05-13 2019-03-31 13F NEWPARK RES COM PAR $.01NEW Call 15,000 137 n/a n/a n/a
2017-05-10 2017-03-31 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-02-15 2016-12-31 13F NEWPARK RES COM PAR $.01NEW Call 2,300 283.33 17 325.00 n/a n/a n/a
2016-11-14 2016-09-30 13F NEWPARK RES COM PAR $.01NEW Call 600 4 n/a n/a n/a
2016-08-12 2016-06-30 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-05-12 2016-03-31 13F NEWPARK RES COM PAR $.01NEW Call 2,000 0.00 9 -18.18 n/a n/a n/a
2016-02-11 2015-12-31 13F NEWPARK RES COM PAR $.01NEW Call 2,000 11 n/a n/a n/a
2015-05-14 2015-03-31 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-02-11 2014-12-31 13F NEWPARK RES COM PAR $.01NEW Call 5,100 920.00 49 716.67 n/a n/a n/a
2014-10-31 2014-09-30 13F NEWPARK RES COM PAR $.01NEW Call 500 0.00 6 0.00 n/a n/a n/a
2014-08-12 2014-06-30 13F NEWPARK RES COM PAR $.01NEW Call 500 400.00 6 500.00 n/a n/a n/a
2013-11-15 2013-09-30 13F NEWPARK RES COM PAR $.01NEW Call 100 0.00 1 0.00 n/a n/a n/a
2013-08-02 2013-06-30 13F NEWPARK RES COM PAR $.01NEW Call 100 1 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2022-05-11 2022-03-31 13F NEWPARK RES COM PAR $.01NEW Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-11 2021-12-31 13F NEWPARK RES COM PAR $.01NEW Put 1,300 -23.53 4 -33.33 n/a n/a n/a
2021-11-12 2021-09-30 13F NEWPARK RES COM PAR $.01NEW Put 1,700 6 n/a n/a n/a
2021-08-10 2021-06-30 13F NEWPARK RES COM PAR $.01NEW Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-05-12 2021-03-31 13F NEWPARK RES COM PAR $.01NEW Put 33,200 66.00 104 173.68 n/a n/a n/a
2021-02-10 2020-12-31 13F NEWPARK RES COM PAR $.01NEW Put 20,000 38 n/a n/a n/a
2020-05-12 2020-03-31 13F NEWPARK RES COM PAR $.01NEW Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-10 2019-12-31 13F NEWPARK RES COM PAR $.01NEW Put 200 -99.65 1 -99.77 n/a n/a n/a
2019-11-12 2019-09-30 13F NEWPARK RES COM PAR $.01NEW Put 57,300 -0.52 437 2.34 n/a n/a n/a
2019-08-09 2019-06-30 13F NEWPARK RES COM PAR $.01NEW Put 57,600 1,125.53 427 690.74 n/a n/a n/a
2014-05-07 2014-03-31 13F NEWPARK RES COM PAR $.01NEW Put 4,700 -37.33 54 -41.30 n/a n/a n/a
2014-01-31 2013-12-31 13F NEWPARK RES COM PAR $.01NEW Put 7,500 -51.61 92 -53.06 n/a n/a n/a
2013-11-15 2013-09-30 13F NEWPARK RES COM PAR $.01NEW Put 15,500 2,114.29 196 2,350.00 n/a n/a n/a
2013-08-02 2013-06-30 13F NEWPARK RES COM PAR $.01NEW Put 700 8 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.