<SEC-DOCUMENT>0000315066-25-002034.txt : 20250806
<SEC-HEADER>0000315066-25-002034.hdr.sgml : 20250806
<ACCEPTANCE-DATETIME>20250806120129
ACCESSION NUMBER:		0000315066-25-002034
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G/A
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20250806
DATE AS OF CHANGE:		20250806

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
		CENTRAL INDEX KEY:			0000860413
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		ORGANIZATION NAME:           	02 Finance
		EIN:				810331430
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-78756
		FILM NUMBER:		251188357

	BUSINESS ADDRESS:	
		STREET 1:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59101
		BUSINESS PHONE:		4062555311

	MAIL ADDRESS:	
		STREET 1:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59101

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
		DATE OF NAME CHANGE:	19930615

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FMR LLC
		CENTRAL INDEX KEY:			0000315066
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		ORGANIZATION NAME:           	
		EIN:				043532603
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		245 SUMMER STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210
		BUSINESS PHONE:		6175706339

	MAIL ADDRESS:	
		STREET 1:		245 SUMMER STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FMR CORP
		DATE OF NAME CHANGE:	19920717
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/schedule13g" xmlns:com="http://www.sec.gov/edgar/common">
 <headerData>
  <submissionType>SCHEDULE 13G/A</submissionType>
  <previousAccessionNumber>0000315066-25-000694</previousAccessionNumber>
  <filerInfo>
   <filer>
    <filerCredentials>
     <cik>0000315066</cik>
     <ccc>XXXXXXXX</ccc>
    </filerCredentials>
   </filer>
   <liveTestFlag>LIVE</liveTestFlag>


  </filerInfo>
 </headerData>
 <formData>
  <coverPageHeader>
   <amendmentNo>1</amendmentNo>
   <securitiesClassTitle>COMMON STOCK</securitiesClassTitle>
   <eventDateRequiresFilingThisStatement>06/30/2025</eventDateRequiresFilingThisStatement>
   <issuerInfo>
    <issuerCik>0000860413</issuerCik>
    <issuerName>FIRST INTERSTATE BANCSYSTEM INC</issuerName>
    <issuerCusip>32055Y201</issuerCusip>
    <issuerPrincipalExecutiveOfficeAddress>
     <com:street1>401 NO 31st Street</com:street1>
     <com:city>Billings</com:city>
     <com:stateOrCountry>MT</com:stateOrCountry>
     <com:zipCode>59101</com:zipCode>
    </issuerPrincipalExecutiveOfficeAddress>
   </issuerInfo>
   <designateRulesPursuantThisScheduleFiled>
    <designateRulePursuantThisScheduleFiled>Rule 13d-1(b)</designateRulePursuantThisScheduleFiled>
   </designateRulesPursuantThisScheduleFiled>
  </coverPageHeader>
  <coverPageHeaderReportingPersonDetails>

   <reportingPersonName>FMR LLC</reportingPersonName>
   <citizenshipOrOrganization>DE</citizenshipOrOrganization>
   <reportingPersonBeneficiallyOwnedNumberOfShares>
    <soleVotingPower>5197876.00</soleVotingPower>
    <sharedVotingPower>0.00</sharedVotingPower>
    <soleDispositivePower>5210135.80</soleDispositivePower>
    <sharedDispositivePower>0.00</sharedDispositivePower>
   </reportingPersonBeneficiallyOwnedNumberOfShares>
   <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>5210135.80</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
   <classPercent>5.0</classPercent>
   <typeOfReportingPerson>HC</typeOfReportingPerson>
  </coverPageHeaderReportingPersonDetails>
  <coverPageHeaderReportingPersonDetails>
   <reportingPersonName>Abigail P. Johnson</reportingPersonName>
   <citizenshipOrOrganization>X1</citizenshipOrOrganization>
   <reportingPersonBeneficiallyOwnedNumberOfShares>
    <soleVotingPower>0.00</soleVotingPower>
    <sharedVotingPower>0.00</sharedVotingPower>
    <soleDispositivePower>5210135.80</soleDispositivePower>
    <sharedDispositivePower>0.00</sharedDispositivePower>
   </reportingPersonBeneficiallyOwnedNumberOfShares>
   <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>5210135.80</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
   <classPercent>5.0</classPercent>
   <typeOfReportingPerson>IN</typeOfReportingPerson>
  </coverPageHeaderReportingPersonDetails>
  <items>
   <item1>
    <issuerName>FIRST INTERSTATE BANCSYSTEM INC</issuerName>
    <issuerPrincipalExecutiveOfficeAddress>401 NO 31st Street,Billings,MT,US,59101</issuerPrincipalExecutiveOfficeAddress>
   </item1>
   <item2>
    <filingPersonName>FMR LLC</filingPersonName>
    <principalBusinessOfficeOrResidenceAddress>245 Summer Street, Boston, Massachusetts 02210</principalBusinessOfficeOrResidenceAddress>
    <citizenship>Not applicable</citizenship>
   </item2>
   <item3>
    <notApplicableFlag>N</notApplicableFlag>
    <typeOfPersonFiling>HC</typeOfPersonFiling>
   </item3>
   <item4>
    <amountBeneficiallyOwned>5210135.80</amountBeneficiallyOwned>
    <classPercent>5.0</classPercent>
    <numberOfSharesPersonHas>
     <solePowerOrDirectToVote>Please see the responses to Items 5 and 6 on the cover page.</solePowerOrDirectToVote>
     <sharedPowerOrDirectToVote>0.00</sharedPowerOrDirectToVote>
     <solePowerOrDirectToDispose>5210135.80</solePowerOrDirectToDispose>
     <sharedPowerOrDirectToDispose>0.00</sharedPowerOrDirectToDispose>
    </numberOfSharesPersonHas>
   </item4>
   <item5>
    <notApplicableFlag>N</notApplicableFlag>
    <classOwnership5PercentOrLess>Y</classOwnership5PercentOrLess>
   </item5>
   <item6>
    <notApplicableFlag>N</notApplicableFlag>
    <ownershipMoreThan5PercentOnBehalfOfAnotherPerson>One or more other persons are known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the COMMON STOCK of FIRST INTERSTATE BANCSYSTEM INC. No one other person's interest in the COMMON STOCK of FIRST INTERSTATE BANCSYSTEM INC is more than five percent of the total outstanding COMMON STOCK.</ownershipMoreThan5PercentOnBehalfOfAnotherPerson>
   </item6>
   <item7>
    <notApplicableFlag>N</notApplicableFlag>
    <subsidiaryIdentificationAndClassification>See attached Exhibit 99.</subsidiaryIdentificationAndClassification>
   </item7>
   <item8>
    <notApplicableFlag>Y</notApplicableFlag>
   </item8>
   <item9>
    <notApplicableFlag>Y</notApplicableFlag>
   </item9>
   <item10>
    <notApplicableFlag>N</notApplicableFlag>
    <certifications>By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.</certifications>
   </item10>
  </items>
  <exhibitInfo>Please see Exhibit 99 for 13d-1(k) (1) agreement.</exhibitInfo>
  <signatureInformation>
   <reportingPersonName>FMR LLC</reportingPersonName>
   <signatureDetails>
    <signature>Richard Bourgelas</signature>
    <title>Duly authorized under Power of Attorney effective as of May 23, 2023, by and on behalf of FMR LLC and its direct and indirect subsidiaries*</title>
    <date>08/05/2025</date>
   </signatureDetails>
  </signatureInformation>
  <signatureInformation>
   <reportingPersonName>Abigail P. Johnson</reportingPersonName>
   <signatureDetails>
    <signature>Richard Bourgelas</signature>
    <title>Duly authorized under Power of Attorney effective as of May 23, 2023, by and on behalf of Abigail P. Johnson*</title>
    <date>08/05/2025</date>
   </signatureDetails>
  </signatureInformation>
  <signatureComments>*This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on August 8, 2023, accession number: 0000315066-23-002397.</signatureComments>
 </formData>

</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99
<SEQUENCE>2
<FILENAME>exhibit99.txt
<TEXT>

Exhibit 99


Pursuant to the instructions in Item 7 of Schedule 13G, the following table
lists the identity and Item 3 classification, if applicable, of each relevant
entity that beneficially owns shares of the security class being reported on
this Schedule 13G.

Entity   ITEM 3 Classification

FIAM LLC  IA
Fidelity Institutional Asset Management Trust Company  BK
Fidelity Management & Research Company LLC  IA
Strategic Advisers LLC  IA


Abigail P. Johnson is a Director, the Chairman and the Chief Executive Officer
of FMR LLC.

Members of the Johnson family, including Abigail P. Johnson, are the
predominant owners, directly or through trusts, of Series B voting common
shares of FMR LLC, representing 49% of the voting power of FMR LLC. The
Johnson family group and all other Series B shareholders have entered into a
shareholders' voting agreement under which all Series B voting common shares
will be voted in accordance with the majority vote of Series B voting common
shares. Accordingly, through their ownership of voting common shares and the
execution of the shareholders' voting agreement, members of the Johnson family
may be deemed, under the Investment Company Act of 1940, to form a controlling
group with respect to FMR LLC.

This filing reflects the securities beneficially owned, or that may be deemed
to be beneficially owned, by FMR LLC, certain of its subsidiaries and
affiliates, and other companies (collectively, the "FMR Reporters"). This
filing does not reflect securities, if any, beneficially owned by certain
other companies whose beneficial ownership of securities is disaggregated from
that of the FMR Reporters in accordance with Securities and Exchange
Commission Release No. 34-39538 (January 12, 1998).


RULE 13d-1(k)(1) AGREEMENT

The undersigned persons, on August 5, 2025, agree and consent to the joint
filing on their behalf of this Schedule 13G in connection with their
beneficial ownership of the COMMON STOCK of FIRST INTERSTATE BANCSYSTEM INC at
June 30, 2025.

FMR LLC

By /s/ Richard Bourgelas
Richard Bourgelas
Duly authorized under Power of Attorney effective as of May 23, 2023, by and
on behalf of FMR LLC and its direct and indirect subsidiaries*

Abigail P. Johnson

By /s/ Richard Bourgelas
Richard Bourgelas
Duly authorized under Power of Attorney effective as of May 23, 2023, by and
on behalf of Abigail P. Johnson*


*This power of attorney is incorporated herein by reference to Exhibit 24 to
the Schedule 13G filed by FMR LLC on August 8, 2023, accession number:
0000315066-23-002397.


</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
