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        <ns3:fridayWeek3>0.9994</ns3:fridayWeek3>
        <ns3:fridayWeek4>0.9994</ns3:fridayWeek4>
        <ns3:fridayWeek5>0.0000</ns3:fridayWeek5>
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      <fridayWeek1>
        <weeklyGrossSubscriptions>21075737.51</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>125290439.26</weeklyGrossRedemptions>
      </fridayWeek1>
      <fridayWeek2>
        <weeklyGrossSubscriptions>269000000.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </fridayWeek2>
      <fridayWeek3>
        <weeklyGrossSubscriptions>26300000.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>316100000.00</weeklyGrossRedemptions>
      </fridayWeek3>
      <fridayWeek4>
        <weeklyGrossSubscriptions>300000000.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </fridayWeek4>
      <fridayWeek5>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </fridayWeek5>
      <totalForTheMonthReported>
        <weeklyGrossSubscriptions>616375737.51</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>366390439.26</weeklyGrossRedemptions>
      </totalForTheMonthReported>
      <sevenDayNetYield>0.0363</sevenDayNetYield>
      <personPayForFundFlag>N</personPayForFundFlag>
    </classLevelInfo>
    <classLevelInfo>
      <classesId>C000231444</classesId>
      <minInitialInvestment>25000000.00</minInitialInvestment>
      <netAssetsOfClass>100953.92</netAssetsOfClass>
      <numberOfSharesOutstanding>100952.7800</numberOfSharesOutstanding>
      <netAssetPerShare>
        <ns3:fridayWeek1>0.9994</ns3:fridayWeek1>
        <ns3:fridayWeek2>0.9994</ns3:fridayWeek2>
        <ns3:fridayWeek3>0.9994</ns3:fridayWeek3>
        <ns3:fridayWeek4>0.9994</ns3:fridayWeek4>
        <ns3:fridayWeek5>0.0000</ns3:fridayWeek5>
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      <fridayWeek1>
        <weeklyGrossSubscriptions>251.86</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
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      <fridayWeek2>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
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      <fridayWeek3>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
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      <fridayWeek4>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </fridayWeek4>
      <fridayWeek5>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </fridayWeek5>
      <totalForTheMonthReported>
        <weeklyGrossSubscriptions>251.86</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>0.00</weeklyGrossRedemptions>
      </totalForTheMonthReported>
      <sevenDayNetYield>0.0363</sevenDayNetYield>
      <personPayForFundFlag>N</personPayForFundFlag>
    </classLevelInfo>
    <classLevelInfo>
      <classesId>C000231963</classesId>
      <minInitialInvestment>25000000.00</minInitialInvestment>
      <netAssetsOfClass>2135818081.50</netAssetsOfClass>
      <numberOfSharesOutstanding>2135819173.1400</numberOfSharesOutstanding>
      <netAssetPerShare>
        <ns3:fridayWeek1>0.9994</ns3:fridayWeek1>
        <ns3:fridayWeek2>0.9994</ns3:fridayWeek2>
        <ns3:fridayWeek3>0.9994</ns3:fridayWeek3>
        <ns3:fridayWeek4>0.9994</ns3:fridayWeek4>
        <ns3:fridayWeek5>0.0000</ns3:fridayWeek5>
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      <fridayWeek1>
        <weeklyGrossSubscriptions>422636511.71</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>308942238.18</weeklyGrossRedemptions>
      </fridayWeek1>
      <fridayWeek2>
        <weeklyGrossSubscriptions>441320677.73</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>554674672.16</weeklyGrossRedemptions>
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      <fridayWeek3>
        <weeklyGrossSubscriptions>174698344.66</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>258086432.10</weeklyGrossRedemptions>
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      <fridayWeek4>
        <weeklyGrossSubscriptions>1037953964.72</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>1235880887.53</weeklyGrossRedemptions>
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      <fridayWeek5>
        <weeklyGrossSubscriptions>0.00</weeklyGrossSubscriptions>
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      <totalForTheMonthReported>
        <weeklyGrossSubscriptions>2191183774.48</weeklyGrossSubscriptions>
        <weeklyGrossRedemptions>2525856687.36</weeklyGrossRedemptions>
      </totalForTheMonthReported>
      <sevenDayNetYield>0.0363</sevenDayNetYield>
      <personPayForFundFlag>N</personPayForFundFlag>
    </classLevelInfo>
    <scheduleOfPortfolioSecuritiesInfo>
      <nameOfIssuer>State Street U.S. Government Money Market Portfolio</nameOfIssuer>
      <titleOfIssuer>State Street U.S. Government Money Market Portfolio</titleOfIssuer>
      <otherUniqueId>FSSgAK161</otherUniqueId>
      <investmentCategory>Investment Company</investmentCategory>
      <securityEligibilityFlag>Y</securityEligibilityFlag>
      <investmentMaturityDateWAM>2022-12-01</investmentMaturityDateWAM>
      <investmentMaturityDateWAL>2022-12-01</investmentMaturityDateWAL>
      <finalLegalInvestmentMaturityDate>2022-12-01</finalLegalInvestmentMaturityDate>
      <securityDemandFeatureFlag>N</securityDemandFeatureFlag>
      <securityGuaranteeFlag>N</securityGuaranteeFlag>
      <securityEnhancementsFlag>N</securityEnhancementsFlag>
      <yieldOfTheSecurityAsOfReportingDate>0.0000</yieldOfTheSecurityAsOfReportingDate>
      <includingValueOfAnySponsorSupport>93225008842.43</includingValueOfAnySponsorSupport>
      <excludingValueOfAnySponsorSupport>93225008842.43</excludingValueOfAnySponsorSupport>
      <percentageOfMoneyMarketFundNetAssets>1.0000</percentageOfMoneyMarketFundNetAssets>
      <securityCategorizedAtLevel3Flag>N</securityCategorizedAtLevel3Flag>
      <dailyLiquidAssetSecurityFlag>Y</dailyLiquidAssetSecurityFlag>
      <weeklyLiquidAssetSecurityFlag>Y</weeklyLiquidAssetSecurityFlag>
      <illiquidSecurityFlag>N</illiquidSecurityFlag>
    </scheduleOfPortfolioSecuritiesInfo>
    <signature>
      <registrant>STATE STREET INSTITUTIONAL INVESTMENT TRUST</registrant>
      <signatureDate>2022-12-07</signatureDate>
      <signature>/s/ Chad Hallett</signature>
      <nameOfSigningOfficer>Chad Hallett</nameOfSigningOfficer>
      <titleOfSigningOfficer>Deputy Treasurer</titleOfSigningOfficer>
    </signature>
  </formData>
</edgarSubmission>
