NPK International Inc.
US ˙ NYSE ˙ US6517185046

SecurityNPKI / NPK International Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership59,689 shares
Latest Disclosed Value $ 864,894
Citadel Advisors Llc ownership in NPKI / NPK International Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 59,689 shares of NPK International Inc. (US:NPKI) valued at $864,894 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 241,640 shares of NPK International Inc.. This represents a change in shares of -75.30% during the quarter. The current value of the position is $852,359 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (NPKI) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 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.

NPKI / 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)
2026-05-15 2026-03-31 13F NPK INTERNATIONAL COM SHS 651718504 59,689 -181,951 -75.30 865 -70.00 0.0001
2026-02-17 2025-12-31 13F NPK INTERNATIONAL COM SHS 651718504 241,640 -282,039 -53.86 2,880 -51.37 0.0004
2025-11-14 2025-09-30 13F NPK INTERNATIONAL COM SHS 651718504 523,679 -168,170 -24.31 5,923 0.59 0.0009
2025-08-14 2025-06-30 13F NPK INTERNATIONAL COM SHS 651718504 691,849 223,237 47.64 5,888 116.27 0.0010
2025-05-15 2025-03-31 13F NPK INTERNATIONAL COM SHS 651718504 468,612 116,109 32.94 2,723 0.70 0.0005
2025-02-14 2024-12-31 13F NPK INTERNATIONAL COM SHS 651718504 352,503 179,888 104.21 2,704 126.00 0.0005
2024-11-14 2024-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 172,615 127,882 285.88 1,196 222.37 0.0002
2024-08-14 2024-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 44,733 -143,617 -76.25 372 -72.70 0.0001
2024-05-15 2024-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 188,350 -270,904 -58.99 1,360 -55.43 0.0003
2024-02-14 2023-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 459,254 103,777 29.19 3,049 24.14 0.0006
2023-11-14 2023-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 355,477 271,982 325.75 2,456 463.30 0.0005
2023-08-14 2023-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 83,495 27,543 49.23 437 102.79 0.0001
2023-05-15 2023-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 55,952 -531,929 -90.48 215 -91.18 0.0000
2023-02-14 2022-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 587,881 570,190 3,223.05 2,440 5,320.00 0.0006
2022-11-14 2022-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 17,691 -21,388 -54.73 45 -62.81 0.0000
2022-08-15 2022-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 39,079 6,964 21.68 121 2.54 0.0000
2022-05-16 2022-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 32,115 -20,232 -38.65 118 -23.38 0.0000
2022-02-14 2021-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 52,347 -33,619 -39.11 154 -45.77 0.0000
2021-11-15 2021-09-30 13F NEWPARK RES Cmn 651718504 85,966 34,393 66.69 284 59.55 0.0001
2021-08-16 2021-06-30 13F NEWPARK RES COM PAR $.01NEW 651718504 51,573 -18,459 -26.36 178 -19.09 0.0000
2021-05-21 2021-03-31 13F/A-1 NEWPARK RES COM PAR $.01NEW 651718504 70,032 40,283 135.41 220 285.96 0.0001
2021-05-17 2021-03-31 13F NEWPARK RES COM PAR $.01NEW 651718504 70,032 40,283 220 0.0001
2021-02-16 2020-12-31 13F NEWPARK RES COM PAR $.01NEW 651718504 29,749 2,044 7.38 57 96.55 0.0000
2020-11-16 2020-09-30 13F NEWPARK RES COM PAR $.01NEW 651718504 27,705 -18,929 -40.59 29 -72.12 0.0000
2020-08-14 2020-06-30 13F NEWPARK RES Cmn 651718504 46,634 -47,741 -50.59 104 22.35 0.0000
2020-05-15 2020-03-31 13F NEWPARK RES Cmn 651718504 94,375 72,533 332.08 85 -37.96 0.0000
2020-02-14 2019-12-31 13F NEWPARK RES Cmn 651718504 21,842 21,842 137 0.0001
2019-08-14 2019-06-30 13F NEWPARK RES Cmn 651718504 0 -13,501 -100.00 0 -100.00
2019-05-15 2019-03-31 13F NEWPARK RES Cmn 651718504 13,501 13,501 124 0.0001
2019-02-14 2018-12-31 13F NEWPARK RES Cmn 651718504 0 -259,719 -100.00 0 -100.00
2018-11-13 2018-09-30 13F NEWPARK RES Cmn 651718504 259,719 135,374 108.87 2,688 99.26 0.0012
2018-08-14 2018-06-30 13F/A-1 NEWPARK RES Cmn 651718504 124,345 8,204 7.06 1,349 43.36 0.0007
2018-08-10 2018-06-30 13F NEWPARK RES Cmn 651718504 124,345 8,204 1,349
2018-05-14 2018-03-31 13F/A-1 NEWPARK RES Cmn 651718504 116,141 70,335 153.55 941 138.83 0.0005
2018-05-11 2018-03-31 13F NEWPARK RES Cmn 651718504 116,141 70,335 941
2018-02-09 2017-12-31 13F NEWPARK RES Cmn 651718504 45,806 45,806 394 0.0002
2017-11-09 2017-09-30 13F NEWPARK RES Cmn 651718504 0 -19,849 -100.00 0 -100.00
2017-08-11 2017-06-30 13F NEWPARK RES Cmn 651718504 19,849 -80,695 -80.26 146 -82.09 0.0001
2017-05-12 2017-03-31 13F NEWPARK RES Cmn 651718504 100,544 -21,778 -17.80 815 -9.44 0.0007
2017-01-31 2016-09-30 13F/A-1 NEWPARK RES Cmn 651718504 122,322 5,197 4.44 900 32.74 0.0009
2016-11-10 2016-09-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 122,322 900
2017-01-31 2016-06-30 13F/A-1 NEWPARK RES Cmn 651718504 117,125 105,435 901.92 678 1,229.41 0.0008
2016-08-12 2016-06-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 117,125 678
2017-01-31 2016-03-31 13F/A-1 NEWPARK RES Cmn 651718504 11,690 -96,092 -89.15 51 -91.04 0.0001
2016-05-13 2016-03-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 11,690 51
2017-01-31 2015-12-31 13F/A-1 NEWPARK RES Cmn 651718504 107,782 107,782 -90.73 569 -93.98 0.0006
2016-02-12 2015-12-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 107,782 569
2015-11-16 2015-09-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 0 -1,162,306 -100.00 0 -100.00
2015-08-14 2015-06-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 1,162,306 67,689 6.18 9,449 -5.24 0.0083
2015-05-15 2015-03-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 1,094,617 1,059,781 3,042.20 9,972 2,903.61 0.0111
2015-02-17 2014-12-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 34,836 33,560 2,630.09 332 1,975.00 0.0004
2014-11-14 2014-09-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 1,276 1,240 3,444.44 16 -99.95 0.0000
2014-08-14 2014-06-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 36 -227,056 -99.98 0 -100.00
2014-05-15 2014-03-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 227,092 -674,413 -74.81 2,600 -76.53 0.0036
2014-02-14 2013-12-31 13F NEWPARK RESOURCES CMN STK Cmn 651718504 901,505 901,275 391,858.70 11,080 369,233.33 0.0144
2013-11-14 2013-09-30 13F NEWPARK RESOURCES CMN STK Cmn 651718504 230 230 3 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
(%)
2026-05-15 2026-03-31 13F NPK INTERNATIONAL COM SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-17 2025-12-31 13F NPK INTERNATIONAL COM SHS Call 12,300 -5.38 147 -0.68 n/a n/a n/a
2025-11-14 2025-09-30 13F NPK INTERNATIONAL COM SHS Call 13,000 147 n/a n/a n/a
2025-08-14 2025-06-30 13F NPK INTERNATIONAL COM SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F NPK INTERNATIONAL COM SHS Call 600 -95.80 3 -97.25 n/a n/a n/a
2025-02-14 2024-12-31 13F NPK INTERNATIONAL COM SHS Call 14,300 472.00 110 541.18 n/a n/a n/a
2024-11-14 2024-09-30 13F NEWPARK RES COM PAR $.01NEW Call 2,500 -74.75 17 -79.27 n/a n/a n/a
2024-08-14 2024-06-30 13F NEWPARK RES COM PAR $.01NEW Call 9,900 421.05 82 530.77 n/a n/a n/a
2024-05-15 2024-03-31 13F NEWPARK RES COM PAR $.01NEW Call 1,900 -64.15 14 -62.86 n/a n/a n/a
2024-02-14 2023-12-31 13F NEWPARK RES COM PAR $.01NEW Call 5,300 -89.46 35 -89.91 n/a n/a n/a
2023-11-14 2023-09-30 13F NEWPARK RES COM PAR $.01NEW Call 50,300 -37.90 348 -17.97 n/a n/a n/a
2023-08-14 2023-06-30 13F NEWPARK RES COM PAR $.01NEW Call 81,000 150.77 424 241.13 n/a n/a n/a
2023-05-15 2023-03-31 13F NEWPARK RES COM PAR $.01NEW Call 32,300 216.67 124 195.24 n/a n/a n/a
2023-02-14 2022-12-31 13F NEWPARK RES COM PAR $.01NEW Call 10,200 42 n/a n/a n/a
2022-11-14 2022-09-30 13F NEWPARK RES COM PAR $.01NEW Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-15 2022-06-30 13F NEWPARK RES COM PAR $.01NEW Call 34,100 5.90 105 -11.02 n/a n/a n/a
2022-05-16 2022-03-31 13F NEWPARK RES COM PAR $.01NEW Call 32,200 -13.67 118 7.27 n/a n/a n/a
2022-02-14 2021-12-31 13F NEWPARK RES COM PAR $.01NEW Call 37,300 1.08 110 -9.84 n/a n/a n/a
2021-11-15 2021-09-30 13F NEWPARK RES Cmn Call 36,900 -13.58 122 -17.57 n/a n/a n/a
2021-08-16 2021-06-30 13F NEWPARK RES COM PAR $.01NEW Call 42,700 -56.34 148 -51.79 n/a n/a n/a
2021-05-21 2021-03-31 13F/A NEWPARK RES COM PAR $.01NEW Call 97,800 137.38 307 288.61 n/a n/a n/a
2021-05-17 2021-03-31 13F NEWPARK RES COM PAR $.01NEW Call 97,800 307 n/a n/a n/a
2021-02-16 2020-12-31 13F NEWPARK RES COM PAR $.01NEW Call 41,200 79 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
(%)
2025-05-15 2025-03-31 13F NPK INTERNATIONAL COM SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-14 2024-12-31 13F NPK INTERNATIONAL COM SHS Put 800 -88.73 6 -87.76 n/a n/a n/a
2024-11-14 2024-09-30 13F NEWPARK RES COM PAR $.01NEW Put 7,100 7,000.00 49 n/a n/a n/a
2024-08-14 2024-06-30 13F NEWPARK RES COM PAR $.01NEW Put 100 -98.39 1 -100.00 n/a n/a n/a
2024-05-15 2024-03-31 13F NEWPARK RES COM PAR $.01NEW Put 6,200 -80.13 45 -78.74 n/a n/a n/a
2024-02-14 2023-12-31 13F NEWPARK RES COM PAR $.01NEW Put 31,200 1,850.00 207 1,781.82 n/a n/a n/a
2023-11-14 2023-09-30 13F NEWPARK RES COM PAR $.01NEW Put 1,600 300.00 11 450.00 n/a n/a n/a
2023-08-14 2023-06-30 13F NEWPARK RES COM PAR $.01NEW Put 400 2 n/a n/a n/a
2022-05-16 2022-03-31 13F NEWPARK RES COM PAR $.01NEW Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-14 2021-12-31 13F NEWPARK RES COM PAR $.01NEW Put 37,700 -27.22 111 -35.09 n/a n/a n/a
2021-11-15 2021-09-30 13F NEWPARK RES Cmn Put 51,800 121.37 171 111.11 n/a n/a n/a
2021-08-16 2021-06-30 13F NEWPARK RES COM PAR $.01NEW Put 23,400 6.36 81 17.39 n/a n/a n/a
2021-05-21 2021-03-31 13F/A NEWPARK RES COM PAR $.01NEW Put 22,000 1.85 69 68.29 n/a n/a n/a
2021-05-17 2021-03-31 13F NEWPARK RES COM PAR $.01NEW Put 22,000 69 n/a n/a n/a
2021-02-16 2020-12-31 13F NEWPARK RES COM PAR $.01NEW Put 21,600 100.00 41 272.73 n/a n/a n/a
2020-11-16 2020-09-30 13F NEWPARK RES COM PAR $.01NEW Put 10,800 0.93 11 -54.17 n/a n/a n/a
2020-08-14 2020-06-30 13F NEWPARK RES Cmn Put 10,700 -10.83 24 118.18 n/a n/a n/a
2020-05-15 2020-03-31 13F NEWPARK RES Cmn Put 12,000 -72.54 11 -95.99 n/a n/a n/a
2020-02-14 2019-12-31 13F NEWPARK RES Cmn Put 43,700 -87.32 274 -89.57 n/a n/a n/a
2019-11-14 2019-09-30 13F NEWPARK RES Cmn Put 344,600 -43.47 2,626 -41.94 n/a n/a n/a
2019-08-14 2019-06-30 13F NEWPARK RES Cmn Put 609,600 4,523 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.