Insider-Transaktionen

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $38.50 to $38.59. 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 Composed of 433,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

Open market or private sale of non-derivative or derivative security

Open market or private sale of non-derivative or derivative security

• F3 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.15 to $37.38. 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.
• F4 Composed of 443,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F5 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.00 to $37.01. 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 Composed of 447,375 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F5 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.90 to $36.91. 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 Composed of 448,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Bona fide gift

• F1 Composed of 1,982,892 shares held of record by James R Scott Trust, James R Scott First Interstate Wealth Management Co-TTEEs, 14,534 shares held of record by James R Scott's 401(k) plan, and 40,870 shares held of record by James R. Scott's spouse.
• F2 As a result of agreements entered into among the reporting persons, the issuer, and other stockholders of the issuer signatory thereto, 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 therein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of his or its pecuniary interest therein. The reporting persons expect to file future Forms 4 or 5, if any, together with James R. Scott with the indication of direct or indirect ownership in Tables I and II being made from James R. Scott's perspective, unless expressly noted otherwise by footnote.

Open market or private sale of non-derivative or derivative security

• F1 Composed of 204,166 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02 (which trust effected the reported sale), 35,233 shares held of record by Juliana Sarah Scott Rose Trust, 35,232 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 As a result of certain agreements entered into among the reporting persons, the Issuer, and 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. The reporting persons disclaim beneficial ownership of any such securities, except to the extent of their pecuniary interests 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.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on September 14, 2027, subject to the reporting person's continued employment through each applicable vesting date.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.10 to $37.44. 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 Composed of 453,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.00 to $37.23. 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 Composed of 461,271 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

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

Bona fide gift

• F1 Composed of 206,866 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 35,233 shares held of record by Juliana Sarah Scott Rose Trust, 35,232 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 As a result of certain agreements entered into among the reporting persons, the Issuer, and 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. The reporting persons disclaim beneficial ownership of any such securities, except to the extent of their pecuniary interests 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.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the vesting date.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.12 to $40.57. 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 Composed of 478,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

• F1 Composed of 218,216 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 35,233 shares held of record by Juliana Sarah Scott Rose Trust, 35,232 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 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.

Open market or private sale of non-derivative or derivative security

• F2 Composed of 213,216 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 35,233 shares held of record by Juliana Sarah Scott Rose Trust, 35,232 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 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.

Open market or private sale of non-derivative or derivative security

• F3 Composed of 208,216 shares held of record by Julie A Scott-Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-02, 35,233 shares held of record by Juliana Sarah Scott Rose Trust, 35,232 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 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.00 to $36.33. 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 Composed of 488,200 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 sharesheld of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.01 to $36.45. 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 Composed of 497,590 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 shares held of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.43 to $35.74. 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 Composed of 502,090 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 shares held of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 vests on June 1, 2029, subject to the reporting person's continued employment through the vesting date.
• F2 The number of shares reported herein reflects a correction to the reporting persons beneficial ownership. A Form 4 filed on March 18, 2026 incorrectly reported that 1,550 shares of common stock were withheld to satisfy tax withholding obligations upon vesting of a previously reported restricted stock award. The correct number of shares withheld for such purpose was 813.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting persons provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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, 2027, subject to the reporting person's provision of continuous service to the Registrant through the earlier of the applicable vesting date or the date of the Registrant's next annual shareholder meeting.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.13 to $35.70. 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 Composed of 514,982 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 shares held of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Open market or private sale of non-derivative or derivative security

• F1 The price reported in column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.31 to $33.55. 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 Composed of 568,486 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, 36,553 shares held of record by Holland Elizabeth Scott Trust, 36,553 shares held of record by Harper Grace Scott Trust, 36,554 shares held of record by Harrison William Scott Trust and 45,200 shares held of record by Jonathan Scott's spouse.
• F3 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.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

• F1 Number of shares of common stock withheld to satisfy the reporting person's tax withholding obligations upon vesting of a previously reported restricted stock unit award.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

• F1 Number of shares of common stock withheld to satisfy the reporting person's tax withholding obligations upon vesting of a previously reported restricted stock unit award.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

• F1 Number of shares of common stock withheld to satisfy the reporting person's tax withholding obligations upon vesting of a previously reported restricted stock unit award.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

• F1 Number of shares of common stock withheld to satisfy the reporting person's tax withholding obligations upon vesting of a previously reported restricted stock unit award.

Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3

• F1 Number of shares of common stock withheld to satisfy the reporting person's tax withholding obligations upon vesting of a previously reported restricted stock unit award.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on March 15, 2027, subject to the reporting person's continued employment through each applicable vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on March 15, 2027, subject to the reporting person's continued employment through each applicable vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on March 15, 2027, subject to the reporting person's continued employment through each applicable vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on March 15, 2027, subject to the reporting person's continued employment through each applicable vesting date.

Grant, award or other acquisition pursuant to Rule 16b-3(d)

• F1 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 in three equal annual installments beginning on March 15, 2027, subject to the reporting person's continued employment through each applicable vesting date.