FIBK

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 12

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA -1

Disclosed balance after: 1,448

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 11

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA - 7

Disclosed balance after: 250

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 10

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA - 6

Disclosed balance after: 500

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 9

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA - 5

Disclosed balance after: 750

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 8

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA - 4

Disclosed balance after: 1,010

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 7

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA -3

Disclosed balance after: 1,290

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 6

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA -2

Disclosed balance after: 1,290

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 5

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · As Custodian under UTMA -1

Disclosed balance after: 1,350

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 4

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 75,762

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 3

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 82,512

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 2

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By IRA

Disclosed balance after: 117,655

F1 · price: The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $29.91 to $29.94. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holder of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon, request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

SEC source: 0000860413-24-000116 · wk-form4_1722552308.xml · nonDerivative · entry 2

HEYNEMAN JOHN M JR · CIK 0001198518 · Director · 10% owner

Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908849 · 10% owner

Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908784 · 10% owner

Towanda Investments Limited Partnership · CIK 0001908810 · 10% owner

John M Heyneman Jr. Trust · CIK 0001908848 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · see footnote

Disclosed balance after: 1,415,701

F1 · kind: Transaction involved a gift of 575 shares to reporting person's spouse and gifts of 575 shares to each of the reporting person's three children that share a household with the reporting person.

F2 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with John Heyneman, Jr. with the indication of direct or indirect ownership in Table I being made from John Heyneman, Jr.'s perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

F3 · ownership.nature: Composed of 150,000 shares held of record by John M Heyneman, Jr. Trust, 85,836 shares held of record by Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust, 85,836 shares held of record by Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust, 1,085,792 shares held of record by Towanda Investments Limited Partnership, 4,552 shares held of record by John Heyneman, Jr.'s spouse, 1,645 shares held of record by John Heyneman, Jr.'s daughter. 1,465 shares held of record by John Heyneman, Jr.'s son Quinn, and 575 shares held of record by John Heyneman, Jr.'s son Bae-John .

SEC source: 0000860413-24-000116 · wk-form4_1722552308.xml · nonDerivative · entry 1

HEYNEMAN JOHN M JR · CIK 0001198518 · Director · 10% owner

Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908849 · 10% owner

Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908784 · 10% owner

Towanda Investments Limited Partnership · CIK 0001908810 · 10% owner

John M Heyneman Jr. Trust · CIK 0001908848 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,166

F1 · kind: Transaction involved a gift of 575 shares to reporting person's spouse and gifts of 575 shares to each of the reporting person's three children that share a household with the reporting person.

SEC source: 0000860413-24-000120 · wk-form4_1722624402.xml · nonDerivative · entry 1

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By IRA

Disclosed balance after: 113,825

SEC source: 0000860413-24-000114 · wk-form4_1722456171.xml · nonDerivative · entry 1

Scott Jonathan R · CIK 0001361935 · Director · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04 · CIK 0001908962 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 987,260

F1 · price: The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.52 to $31.64. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holder of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon, request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F2 · ownership.nature: Composed of 595,872 shares held of record by Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04, 209,678 shares held of record by IXL Limited Liability Company, 43,903 shares held of record by Holland Elizabeth Scott Trust, 43,903 shares held of record by Harper Grace Scott Trust, 43,904 shares held of record by Harrison William Scott Trust and 50,000 shares held of record by Jonathan Scott's spouse.

F3 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Jonathan R. Scott with the indication of direct or indirect ownership in Table I and Table II being made from Jonathan R. Scott's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0000860413-24-000104 · wk-form4_1718318792.xml · nonDerivative · entry 2

Scott Jonathan R · CIK 0001361935 · Director · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04 · CIK 0001908962 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 1,007,260

F4 · price: 3. The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $25.75 to $26.49. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F3 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Jonathan R. Scott with the indication of direct or indirect ownership in Table I and Table II being made from Jonathan R. Scott's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

F5 · ownership.nature: Composed of 615,872 shares held of record by Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04, 209,678 shares held of record by IXL Limited Liability Company, 43,903 shares held of record by Holland Elizabeth Scott Trust, 43,903 shares held of record by Harper Grace Scott Trust, 43,904 shares held of record by Harrison William Scott Trust and 50,000 shares held of record by Jonathan Scott's spouse.

SEC source: 0001493152-24-023650 · ownership.xml · nonDerivative · entry 2

SCOTT JULIE A · CIK 0001234619 · 10% owner

Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002 · CIK 0001908851 · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Juliana Sarah Scott Rose Trust · CIK 0001909078 · 10% owner

Elizabeth Lauren Scott Rose Trust · CIK 0001908961 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 727,439

F3 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $25.75 to $26.49. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F4 · balance_after: Composed of 236,986 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 43,903 shares held of record by Holland Elizabeth Scott Trust, 43,903 shares held of record by Harper Grace Scott Trust, 43,904 shares held of record by Harrison William Scott Trust, 74,533 shares held of record by Juliana Sarah Scott Rose Trust, 74,532 shares held of record by Elizabeth Lauren Scott Rose Trust, and 209,678 shares held by IXL Limited Liability Company, over which Ms. Rose has shared voting and dispositive power with a sibling.

F4 · ownership.nature: Composed of 236,986 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 43,903 shares held of record by Holland Elizabeth Scott Trust, 43,903 shares held of record by Harper Grace Scott Trust, 43,904 shares held of record by Harrison William Scott Trust, 74,533 shares held of record by Juliana Sarah Scott Rose Trust, 74,532 shares held of record by Elizabeth Lauren Scott Rose Trust, and 209,678 shares held by IXL Limited Liability Company, over which Ms. Rose has shared voting and dispositive power with a sibling.

F5 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Julie Scott Rose with the indication of direct or indirect ownership in Table I and Table II being made from Julie Scott Rose's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0000860413-24-000104 · wk-form4_1718318792.xml · nonDerivative · entry 1

Scott Jonathan R · CIK 0001361935 · Director · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04 · CIK 0001908962 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 1,021,663

F1 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $25.14 to $25.42. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F2 · ownership.nature: Composed of 615,872 shares held of record by Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04, 209,678 shares held of record by IXL Limited Liability Company, 48,704 shares held of record by Holland Elizabeth Scott Trust, 48,704 shares held of record by Harper Grace Scott Trust, 48,705 shares held of record by Harrison William Scott Trust and 50,000 shares held of record by Jonathan Scott's spouse.

F3 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Jonathan R. Scott with the indication of direct or indirect ownership in Table I and Table II being made from Jonathan R. Scott's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0001493152-24-023650 · ownership.xml · nonDerivative · entry 1

SCOTT JULIE A · CIK 0001234619 · 10% owner

Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002 · CIK 0001908851 · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Juliana Sarah Scott Rose Trust · CIK 0001909078 · 10% owner

Elizabeth Lauren Scott Rose Trust · CIK 0001908961 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 879,869

F1 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $25.14 to $25.42. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F2 · balance_after: Composed of 293,831 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 48,704 shares held of record by Holland Elizabeth Scott Trust, 48,704 shares held of record by Harper Grace Scott Trust, 48,705 shares held of record by Harrison William Scott Trust, 90,124 shares held of record by Juliana Sarah Scott Rose Trust, 90,123 shares held of record by Elizabeth Lauren Scott Rose Trust, and 209,678 shares held by IXL Limited Liability Company, over which Ms. Rose has shared voting and dispositive power with a sibling.

F2 · ownership.nature: Composed of 293,831 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 48,704 shares held of record by Holland Elizabeth Scott Trust, 48,704 shares held of record by Harper Grace Scott Trust, 48,705 shares held of record by Harrison William Scott Trust, 90,124 shares held of record by Juliana Sarah Scott Rose Trust, 90,123 shares held of record by Elizabeth Lauren Scott Rose Trust, and 209,678 shares held by IXL Limited Liability Company, over which Ms. Rose has shared voting and dispositive power with a sibling.

F5 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Julie Scott Rose with the indication of direct or indirect ownership in Table I and Table II being made from Julie Scott Rose's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0000860413-24-000101 · wk-form4_1717538763.xml · nonDerivative · entry 1

SCOTT JAMES R · CIK 0001198533 · Director · 10% owner

Foundation for Community Vitality · CIK 0001908742 · 10% owner

J.S. Investments Limited Partnership · CIK 0001506291 · 10% owner

James F Heyneman Conservatorship, James Scott, Conservator · CIK 0001908854 · 10% owner

James F Heyneman Trust, James Scott & First Interstate Wealth Management Co-Trustees · CIK 0001908844 · 10% owner

James R Scott Trust, James R Scott & First Interstate Wealth Management Co-TTEEs · CIK 0001908712 · 10% owner

James R & Christine M Scott Foundation · CIK 0001909853 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,333

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000100 · wk-form4_1717538747.xml · nonDerivative · entry 1

HEYNEMAN JOHN M JR · CIK 0001198518 · Director · 10% owner

John M Heyneman Jr. Trust · CIK 0001908848 · 10% owner

Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908849 · 10% owner

Towanda Investments Limited Partnership · CIK 0001908810 · 10% owner

Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust · CIK 0001908784 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,466

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000097 · wk-form4_1717531486.xml · nonDerivative · entry 1

Grieb Frances Pallas · CIK 0001622140 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,450

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000095 · wk-form4_1717531455.xml · nonDerivative · entry 1

Johnson Dennis L · CIK 0001572624 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,262

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000096 · wk-form4_1717531471.xml · nonDerivative · entry 1

Lacy Stephen Mark · CIK 0001652090 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,888

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000094 · wk-form4_1717531442.xml · nonDerivative · entry 1

Scott Jonathan R · CIK 0001361935 · Director · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

IXL Ltd Liability Co · CIK 0001909090 · 10% owner

Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04 · CIK 0001908962 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,114

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000089 · wk-form4_1717530476.xml · nonDerivative · entry 1

HENNING THOMAS EDWARD · CIK 0001269806 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,066

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000088 · wk-form4_1717530463.xml · nonDerivative · entry 1

Bowman Biff · CIK 0001548048 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,894

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000087 · wk-form4_1717530448.xml · nonDerivative · entry 1

MOSS PATRICIA L · CIK 0001190817 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,116

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000086 · wk-form4_1717530434.xml · nonDerivative · entry 1

Jahnke David L · CIK 0001527851 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,555

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000085 · wk-form4_1717530422.xml · nonDerivative · entry 1

Phillips Joyce Ann · CIK 0001594614 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,406

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000084 · wk-form4_1717530409.xml · nonDerivative · entry 1

RYKHUS DANIEL A · CIK 0001284209 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,060

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000083 · wk-form4_1717530395.xml · nonDerivative · entry 1

Cho Alice S · CIK 0001812520 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,599

F1 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2023 Equity and Incentive Plan. The restricted stock units vest on June 1, 2025, subject to the reporting persons provision of continuous service to the Registrant through the vesting date.

SEC source: 0000860413-24-000075 · wk-form4_1717018882.xml · nonDerivative · entry 1

Robbins Kristina · CIK 0001930719 · EVP, Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,220

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0001493152-24-019770 · ownership.xml · nonDerivative · entry 3

SCOTT JULIE A · CIK 0001234619 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002 · CIK 0001908851 · 10% owner

Juliana Sarah Scott Rose Trust · CIK 0001909078 · 10% owner

Elizabeth Lauren Scott Rose Trust · CIK 0001908961 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 776,022

F1 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $27.44 to $27.71. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F4 · balance_after: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 95,065 shares held of record by Juliana Sarah Scott Rose Trust, 95,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F4 · ownership.nature: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 95,065 shares held of record by Juliana Sarah Scott Rose Trust, 95,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F5 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Julie Scott Rose with the indication of direct or indirect ownership in Table I and Table II being made from Julie Scott Rose's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0001493152-24-019770 · ownership.xml · nonDerivative · entry 2

SCOTT JULIE A · CIK 0001234619 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002 · CIK 0001908851 · 10% owner

Juliana Sarah Scott Rose Trust · CIK 0001909078 · 10% owner

Elizabeth Lauren Scott Rose Trust · CIK 0001908961 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 803,022

F1 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $27.44 to $27.71. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F3 · balance_after: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 95,065 shares held of record by Juliana Sarah Scott Rose Trust, 122,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F3 · ownership.nature: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 95,065 shares held of record by Juliana Sarah Scott Rose Trust, 122,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F5 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Julie Scott Rose with the indication of direct or indirect ownership in Table I and Table II being made from Julie Scott Rose's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0001493152-24-019770 · ownership.xml · nonDerivative · entry 1

SCOTT JULIE A · CIK 0001234619 · 10% owner

Harrison William Scott Trust · CIK 0001908873 · 10% owner

Holland Elizabeth Scott Trust · CIK 0001908953 · 10% owner

Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002 · CIK 0001908851 · 10% owner

Juliana Sarah Scott Rose Trust · CIK 0001909078 · 10% owner

Elizabeth Lauren Scott Rose Trust · CIK 0001908961 · 10% owner

Harper Grace Scott Trust · CIK 0001908895 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 830,022

F1 · price: The price reported in column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $27.44 to $27.71. The reporting person undertakes to provide to First Interstate BancSystem, Inc., any security holders of First Interstate BancSystem, Inc., or the staff of the Securities and Exchange Commission, upon request, the full information regarding the number of shares sold at each separate price within the ranges set forth above.

F2 · balance_after: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 122,065 shares held of record by Juliana Sarah Scott Rose Trust, 122,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F2 · ownership.nature: Composed of 410,281 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 58,537 shares held of record by Holland Elizabeth Scott Trust, 58,537 shares held of record by Harper Grace Scott Trust, 58,538 shares held of record by Harrison William Scott Trust, 122,065 shares held of record by Juliana Sarah Scott Rose Trust, 122,064 shares held of record by Elizabeth Lauren Scott Rose Trust.

F5 · ownership.nature: As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4 and 5, if any, together with Julie Scott Rose with the indication of direct or indirect ownership in Table I and Table II being made from Julie Scott Rose's perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

SEC source: 0000860413-25-000074 · wk-form4_1748625714.xml · nonDerivative · entry 3

Scott James R. Jr · CIK 0001675872 · Director · 10% owner

First Interstate Bank TTEE for Dana S Andersson GST Exempt Trust No 1 Dtd 12/11/2020 · CIK 0001910215 · 10% owner

First Interstate Bank TTEE for James R Scott Jr. GST Exempt Trust No 1 Dtd 12/11/2020 · CIK 0001910352 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 76,155

F3 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of restricted stock units.

SEC source: 0000860413-24-000034 · wk-form4_1710888187.xml · nonDerivative · entry 3

KNIERIEM KARLYN M · CIK 0001741432 · EVP, Chief Risk Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,084

F2 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2024 Equity and Incentive Plan. The restricted stock units vest in three equal annual installments beginning on March 15, 2025, subject to the reporting person's continued employment through each applicable vesting date.

SEC source: 0000860413-24-000034 · wk-form4_1710888187.xml · nonDerivative · entry 2

KNIERIEM KARLYN M · CIK 0001741432 · EVP, Chief Risk Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,992

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000034 · wk-form4_1710888187.xml · nonDerivative · entry 1

KNIERIEM KARLYN M · CIK 0001741432 · EVP, Chief Risk Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 20,359

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000032 · wk-form4_1710888033.xml · nonDerivative · entry 4

Mutch Marcy D · CIK 0001653911 · Exec. Vice Pres. & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 61,633

F2 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2024 Equity and Incentive Plan. The restricted stock units vest in three equal annual installments beginning on March 15, 2025, subject to the reporting person's continued employment through each applicable vesting date.

SEC source: 0000860413-24-000032 · wk-form4_1710888033.xml · nonDerivative · entry 3

Mutch Marcy D · CIK 0001653911 · Exec. Vice Pres. & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,274

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000032 · wk-form4_1710888033.xml · nonDerivative · entry 2

Mutch Marcy D · CIK 0001653911 · Exec. Vice Pres. & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,942

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000032 · wk-form4_1710888033.xml · nonDerivative · entry 1

Mutch Marcy D · CIK 0001653911 · Exec. Vice Pres. & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 52,466

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000030 · wk-form4_1710887871.xml · nonDerivative · entry 5

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 89,812

F3 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2024 Equity and Incentive Plan. The restricted stock units vest in three equal annual installments beginning on March 15, 2025, subject to the reporting person's continued employment through each applicable vesting date.

SEC source: 0000860413-24-000030 · wk-form4_1710887871.xml · nonDerivative · entry 4

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 50,701

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000030 · wk-form4_1710887871.xml · nonDerivative · entry 3

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 53,650

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000030 · wk-form4_1710887871.xml · nonDerivative · entry 2

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,521

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

SEC source: 0000860413-24-000030 · wk-form4_1710887871.xml · nonDerivative · entry 1

RILEY KEVIN P · CIK 0001408733 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,427

F1 · shares: Disposition to the issuer of issuer securities in payment of minimum required withholding taxes due upon vesting of unvested shares.

F2 · balance_after: Excludes 1300 shares previously owned Direct that were transferred to Indirect IRA holdings 12/31/23.

SEC source: 0000860413-24-000028 · wk-form4_1710887489.xml · nonDerivative · entry 4

Robbins Kristina · CIK 0001930719 · EVP, Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,441

F2 · shares: Shares issuable upon vesting of restricted stock units granted to the reporting person pursuant to the Registrant's 2024 Equity and Incentive Plan. The restricted stock units vest in three equal annual installments beginning on March 15, 2025, subject to the reporting person's continued employment through each applicable vesting date.