<SEC-DOCUMENT>0001104659-25-059852.txt : 20250616
<SEC-HEADER>0001104659-25-059852.hdr.sgml : 20250616
<ACCEPTANCE-DATETIME>20250616160437
ACCESSION NUMBER:		0001104659-25-059852
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20250616
FILED AS OF DATE:		20250616
DATE AS OF CHANGE:		20250616

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Riefberg Vivian E.
		CENTRAL INDEX KEY:			0001843139
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42125
		FILM NUMBER:		251050028

	MAIL ADDRESS:	
		STREET 1:		800 CONNECTICUT AVENUE
		CITY:			NORWALK
		STATE:			CT
		ZIP:			06854

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Waystar Holding Corp.
		CENTRAL INDEX KEY:			0001990354
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
		ORGANIZATION NAME:           	06 Technology
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1550 DIGITAL DRIVE, #300
		CITY:			LEHI
		STATE:			UT
		ZIP:			84043
		BUSINESS PHONE:		844-492-9782

	MAIL ADDRESS:	
		STREET 1:		1550 DIGITAL DRIVE, #300
		CITY:			LEHI
		STATE:			UT
		ZIP:			84043
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2518062-5_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-06-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001990354</issuerCik>
        <issuerName>Waystar Holding Corp.</issuerName>
        <issuerTradingSymbol>WAY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001843139</rptOwnerCik>
            <rptOwnerName>Riefberg Vivian E.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1550 DIGITAL DRIVE, #300</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LEHI</rptOwnerCity>
            <rptOwnerState>UT</rptOwnerState>
            <rptOwnerZipCode>84043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-06-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5134</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13829</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reflects a grant of restricted stock units (&quot;RSUs&quot;) which vest on the earlier of (i) June 4, 2026 and (ii) the first regularly scheduled annual meeting of the stockholders following the grant date. Each RSU represents a contingent right to receive one share of Common Stock upon settlement.</footnote>
        <footnote id="F2">Includes unvested RSUs.</footnote>
    </footnotes>

    <remarks>Exhibit 24 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Gregory R. Packer, as Attorney-in-Fact</signatureName>
        <signatureDate>2025-06-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>tm2518062d5_ex24.htm
<DESCRIPTION>EXHIBIT 24
<TEXT>
<HTML>
<HEAD>
     <TITLE></TITLE>
</HEAD>
<BODY STYLE="font: 10pt Times New Roman, Times, Serif">

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><B>Exhibit 24</B></P>

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Power of Attorney</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Know all by these presents that the undersigned, does hereby make,
constitute and appoint each of GREGORY R. PACKER and STEVEN M. ORESKOVICH, or any one of them, as a true and lawful attorney-in-fact
of the undersigned with full powers of substitution and revocation, for and in the name, place and stead of the undersigned (in the undersigned&rsquo;s
individual capacity), to execute and deliver such forms that the undersigned may be required to file with the U.S. Securities and Exchange
Commission as a result of the undersigned&rsquo;s ownership of or transactions in securities of WAYSTAR HOLDING CORP. (i) pursuant to
Section 16(a) of the Securities Exchange Act of 1934, as amended, including without limitation, statements on Form 3, Form 4 and Form
5 (including any amendments thereto) and (ii) in connection with any applications for EDGAR access codes, including without limitation
the Form ID. The Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 3,
4 and 5 with regard to his or her ownership of or transactions in securities of WAYSTAR HOLDING CORP., unless earlier revoked in writing.
The undersigned acknowledges that GREGORY R. PACKER and STEVEN M. ORESKOVICH are not assuming any of the undersigned&rsquo;s responsibilities
to comply with Section 16 of the Securities Exchange Act of 1934, as amended.&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
  <TR STYLE="vertical-align: top">
    <TD STYLE="width: 50%; text-align: right">&nbsp;</TD>
    <TD STYLE="width: 5%; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">By:</FONT>&nbsp;</TD>
    <TD STYLE="border-bottom: Black 1pt solid; width: 45%"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">/s/ Vivian E. Riefberg</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="text-align: right">&nbsp;</TD>
    <TD STYLE="text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Name:</FONT>&nbsp;</TD>
    <TD><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Vivian E. Riefberg</FONT></TD></TR>
  <TR STYLE="vertical-align: top">
    <TD STYLE="text-align: right">&nbsp;</TD>
    <TD STYLE="text-align: right">&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  <TR STYLE="vertical-align: top">
    <TD><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Date: June 13, 2025</FONT></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD></TR>
  </TABLE>

<P STYLE="margin: 0">&nbsp;</P>

<P STYLE="margin: 0"></P>

<!-- Field: Page; Sequence: 1; Options: Last -->
    <DIV STYLE="margin-top: 12pt; margin-bottom: 6pt; border-bottom: Black 1pt solid"><P STYLE="margin: 0pt">&nbsp;</P></DIV>
    <!-- Field: /Page -->

<P STYLE="margin: 0">&nbsp;</P>

</BODY>
</HTML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
