<SEC-DOCUMENT>0001880836-26-000004.txt : 20260603
<SEC-HEADER>0001880836-26-000004.hdr.sgml : 20260603
<ACCEPTANCE-DATETIME>20260603185145
ACCESSION NUMBER:		0001880836-26-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260601
FILED AS OF DATE:		20260603
DATE AS OF CHANGE:		20260603

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Briggs Lori
		CENTRAL INDEX KEY:			0001880836
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-02960
		FILM NUMBER:		261062628

	MAIL ADDRESS:	
		STREET 1:		9320 LAKESIDE BOULEVARD
		STREET 2:		SUITE 100
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NPK International Inc.
		CENTRAL INDEX KEY:			0000071829
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MISCELLANEOUS EQUIPMENT RENTAL & LEASING [7350]
		ORGANIZATION NAME:           	07 Trade & Services
		EIN:				721123385
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		9320 LAKESIDE BOULEVARD
		STREET 2:		SUITE 100
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381
		BUSINESS PHONE:		281-362-6800

	MAIL ADDRESS:	
		STREET 1:		9320 LAKESIDE BOULEVARD
		STREET 2:		SUITE 100
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NEWPARK RESOURCES INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NEW PARK MINING CO
		DATE OF NAME CHANGE:	19720828
</SEC-HEADER>
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<TYPE>4
<SEQUENCE>1
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<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-06-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000071829</issuerCik>
        <issuerName>NPK International Inc.</issuerName>
        <issuerTradingSymbol>NPKI</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001880836</rptOwnerCik>
            <rptOwnerName>Briggs Lori</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>9320 LAKESIDE BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 100</rptOwnerStreet2>
            <rptOwnerCity>THE WOODLANDS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77381</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP &amp; President, Ind. Solutions</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>1</aff10b5One>

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                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>5401</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.31</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>257950</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
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                    <value>D</value>
                </directOrIndirectOwnership>
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                <value>Common Stock</value>
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                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionShares>
                    <value>9577</value>
                    <footnoteId id="F1"/>
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                <transactionPricePerShare>
                    <value>14.31</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>248373</value>
                </sharesOwnedFollowingTransaction>
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        <nonDerivativeTransaction>
            <securityTitle>
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            <transactionDate>
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                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                    <footnoteId id="F1"/>
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                <transactionAcquiredDisposedCode>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
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            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>24340</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>265936</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-06-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10446</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.5776</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>255490</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-06-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>24340</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>24340</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares withheld to satisfy tax withholding obligations upon the vesting of restricted stock units.</footnote>
        <footnote id="F2">The restricted stock units vest and convert into shares on a one-for-one basis.</footnote>
        <footnote id="F3">The reported sale of 10,446 shares occurred automatically pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 15, 2025.</footnote>
        <footnote id="F4">The price reported is the weighted average price. These shares were sold in multiple transactions in the open market at prices ranging from $14.33 to $14.74, inclusive. The reporting person undertakes to provide to NPK International Inc., any security holder of NPK International Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnote (2) to this Form 4.</footnote>
        <footnote id="F5">Grant of restricted stock units that vest in one-third increments on June 1 of each subsequent year after grant and settle in shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: M. Celeste Fruge For: Lori Briggs</signatureName>
        <signatureDate>2026-06-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
