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        <com:street2>SUITE 201</com:street2>
        <com:city>ANDOVER</com:city>
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      <relationshipsToIssuer>
        <relationshipToIssuer>Director</relationshipToIssuer>
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        <address>
          <com:street1>900 Salem Street</com:street1>
          <com:city>Smithfield</com:city>
          <com:stateOrCountry>RI</com:stateOrCountry>
          <com:zipCode>02917</com:zipCode>
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      </brokerOrMarketmakerDetails>
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      <aggregateMarketValue>19432.00</aggregateMarketValue>
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      <approxSaleDate>06/01/2023</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
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      <securitiesClassTitle>Common</securitiesClassTitle>
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      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>200</amountOfSecuritiesAcquired>
      <paymentDate>05/10/2021</paymentDate>
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    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
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          <com:street1>2 Tech Drive</com:street1>
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          <com:stateOrCountry>MA</com:stateOrCountry>
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      <grossProceeds>17334.00</grossProceeds>
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      <planAdoptionDates>
        <planAdoptionDate>08/01/2022</planAdoptionDate>
      </planAdoptionDates>
      <signature>/s/ Daniel Tucci, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Elizabeth Mora</signature>
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144
0001548935
XXXXXXXX
LIVE
0001049502
MKS INSTRUMENTS INC
000-23621
2 TECH DRIVE
SUITE 201
ANDOVER
MA
01810
978-645-5500
Mora Elizabeth
Director
Common
Fidelity Brokerage Services LLC
900 Salem Street
Smithfield
RI
02917
200
19432.00
66767385
06/01/2023
NASDAQ
Common
05/10/2021
Restricted Stock Vesting
Issuer
N
200
05/10/2021
Compensation
N
Elizabeth Mora
2 Tech Drive
Suite 201
Andover
MA
01810
Common
03/15/2023
200
17334.00
06/01/2023
08/01/2022
/s/ Daniel Tucci, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Elizabeth Mora