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            <filer>
                <filerCredentials>
                    <cik>0001998250</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001990354</issuerCik>
            <issuerName>WAYSTAR HOLDING CORP</issuerName>
            <secFileNumber>001-42125</secFileNumber>
            <issuerAddress>
                <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                <ns2:city>Lehi</ns2:city>
                <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                <ns2:zipCode>84043</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>8444929782</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>ERIC LEE SINCLAIR III</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>38806</noOfUnitsSold>
            <aggregateMarketValue>1424180.20</aggregateMarketValue>
            <noOfUnitsOutstanding>173018999</noOfUnitsOutstanding>
            <approxSaleDate>07/21/2025</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>07/21/2025</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>38806</amountOfSecuritiesAcquired>
            <paymentDate>07/21/2025</paymentDate>
            <natureOfPayment>Cash</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for ERIC L SINCLAIR III</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>06/25/2025</saleDate>
            <amountOfSecuritiesSold>9702</amountOfSecuritiesSold>
            <grossProceeds>390256.16</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for ERIC L SINCLAIR III</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>06/20/2025</saleDate>
            <amountOfSecuritiesSold>9702</amountOfSecuritiesSold>
            <grossProceeds>366616.27</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for ERIC L SINCLAIR III</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/30/2025</saleDate>
            <amountOfSecuritiesSold>9702</amountOfSecuritiesSold>
            <grossProceeds>388080.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for ERIC L SINCLAIR III</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/21/2025</saleDate>
            <amountOfSecuritiesSold>9702</amountOfSecuritiesSold>
            <grossProceeds>379970.10</grossProceeds>
        </securitiesSoldInPast3Months>
        <remarks>The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.&#13;
</remarks>
        <noticeSignature>
            <noticeDate>07/21/2025</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>02/19/2025</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ ERIC LEE SINCLAIR III</signature>
        </noticeSignature>
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144
0001998250
XXXXXXXX
LIVE
0001990354
WAYSTAR HOLDING CORP
001-42125
1550 Digital Drive, #300
Lehi
UT
84043
8444929782
ERIC LEE SINCLAIR III
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
38806
1424180.20
173018999
07/21/2025
NASDAQ
Common
07/21/2025
Exercise of Stock Options
Issuer
N
38806
07/21/2025
Cash
N
10b5-1 Sales for ERIC L SINCLAIR III
1550 Digital Drive, #300
Lehi
UT
84043
Common
06/25/2025
9702
390256.16
10b5-1 Sales for ERIC L SINCLAIR III
1550 Digital Drive, #300
Lehi
UT
84043
Common
06/20/2025
9702
366616.27
10b5-1 Sales for ERIC L SINCLAIR III
1550 Digital Drive, #300
Lehi
UT
84043
Common
05/30/2025
9702
388080.00
10b5-1 Sales for ERIC L SINCLAIR III
1550 Digital Drive, #300
Lehi
UT
84043
Common
05/21/2025
9702
379970.10
The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.
07/21/2025
02/19/2025
/s/ ERIC LEE SINCLAIR III