<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-06-27</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000041719</issuerCik>
        <issuerName>Glatfelter Corp</issuerName>
        <issuerTradingSymbol>GLT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056973</rptOwnerCik>
            <rptOwnerName>CARLSON CAPITAL L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 MCKINNEY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1900</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001613525</rptOwnerCik>
            <rptOwnerName>Black Diamond Arbitrage Offshore Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 MCKINNEY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1900</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001951606</rptOwnerCik>
            <rptOwnerName>EDCA 2019 Fund, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 MCKINNEY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1900</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001503915</rptOwnerCik>
            <rptOwnerName>Asgard Investment Corp. II</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 MCKINNEY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1900</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001404625</rptOwnerCik>
            <rptOwnerName>Carlson Clint Duane</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2100 MCKINNEY AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1900</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>false</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share (the &quot;Common Stock&quot;)</value>
            </securityTitle>
            <transactionDate>
                <value>2024-06-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>207325</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.65</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6968675</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-06-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2262984</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.40</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4705691</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The transactions referenced herein provide for various per share prices ranging from $1.630146 to $1.79. The Reporting Persons undertake to provide to the Staff of the Securities and Exchange Commission or any security holder of the Issuer, upon request, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F2">Transaction reflects direct disposition by Black Diamond Arbitrage Offshore Ltd., a Cayman Islands exempted company (&quot;Arbitrage&quot;) of 161,133 shares and by EDCA 2019 Fund, L.P., a Delaware limited partnership (&quot;EDCA,&quot; together with Double Offshore and Arbitrage, the &quot;Funds&quot;) of 46,192 shares.</footnote>
        <footnote id="F3">Carlson Capital, L.P., a Delaware limited partnership (&quot;Carlson Capital&quot;) serves as the investment manager to, and has the power to direct the affairs of, the Funds. Asgard Investment Corp. II, a Delaware corporation (&quot;Asgard II&quot;) serves as the general partner of, and has the power to direct the affairs of, Carlson Capital. Mr. Clint D. Carlson, a U.S. citizen, serves as the president of, and has the power to direct the affairs of, Asgard II and Carlson Capital. Each of the reporting persons disclaims beneficial ownership of the securities to which this Form 4 relates for the purposes of Section 16 of the Securities and Exchange Act of 1934, as amended, except as to such extent of the reporting person's pecuniary interest in the securities.</footnote>
        <footnote id="F4">The transactions referenced herein provide for various per share prices ranging from $1.39 to $1.620557. The Reporting Persons undertake to provide to the Staff of the Securities and Exchange Commission or any security holder of the Issuer, upon request, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F5">Transaction reflects direct disposition by Arbitrage of 1,758,784 shares and by EDCA of 504,200 shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Carlson Capital, L.P., By: /s/ Clint D. Carlson, Title: President</signatureName>
        <signatureDate>2024-07-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Black Diamond Arbitrage Offshore Ltd., By its investment manager Carlson Capital, L.P., By its general partner Asgard II, By: /s/ Clint D. Carlson, Title: President</signatureName>
        <signatureDate>2024-07-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>EDCA 2019 Fund, L.P., By its investment manager Carlson Capital, L.P., By its general partner Asgard II, By: /s/ Clint D. Carlson, Title: President</signatureName>
        <signatureDate>2024-07-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Asgard Investment Corp. II, By: /s/ Clint D. Carlson, Title: President</signatureName>
        <signatureDate>2024-07-01</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Clint D. Carlson, By: /s/ Clint D. Carlson</signatureName>
        <signatureDate>2024-07-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
