0000860413 2025-01-01 2025-12-31 0000860413 fibk:KevinRileyMember 2025-01-01 2025-12-31 0000860413 fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:KevinRileyMember 2024-01-01 2024-12-31 0000860413 fibk:JamesReuterMember 2024-01-01 2024-12-31 0000860413 2024-01-01 2024-12-31 0000860413 fibk:KevinRileyMember 2023-01-01 2023-12-31 0000860413 fibk:JamesReuterMember 2023-01-01 2023-12-31 0000860413 2023-01-01 2023-12-31 0000860413 fibk:KevinRileyMember 2022-01-01 2022-12-31 0000860413 fibk:JamesReuterMember 2022-01-01 2022-12-31 0000860413 2022-01-01 2022-12-31 0000860413 fibk:KevinRileyMember 2021-01-01 2021-12-31 0000860413 fibk:JamesReuterMember 2021-01-01 2021-12-31 0000860413 2021-01-01 2021-12-31 0000860413 fibk:GrantDateFairValueOfOptionAwardsAndStockAwardsGrantedInYearMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:GrantDateFairValueOfOptionAwardsAndStockAwardsGrantedInYearMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtYearEndOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtYearEndOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearMember 2025-01-01 2025-12-31 0000860413 fibk:ChangeInFairValueOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearPriorFiscalYearsMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:ChangeInFairValueOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearPriorFiscalYearsMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtVestingOfOptionAndStockAwardsGrantedInYearThatVestedDuringFiscalYearMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtVestingOfOptionAndStockAwardsGrantedInYearThatVestedDuringFiscalYearMember 2025-01-01 2025-12-31 0000860413 fibk:ChangeInFairValueAsOfVestingDateOfOptionAndStockAwardsGrantedInPriorFiscalYearsForWhichApplicableVestingConditionsWereSatisfiedDuringYearMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:ChangeInFairValueAsOfVestingDateOfOptionAndStockAwardsGrantedInPriorFiscalYearsForWhichApplicableVestingConditionsWereSatisfiedDuringYearMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtFiscalYearEndOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:FairValueAtFiscalYearEndOfOutstandingAndUnvestedOptionAndStockAwardsGrantedInYearMember 2025-01-01 2025-12-31 0000860413 fibk:ValueOfDividendsOrOtherEarningsPaidOnStockOrOptionAwardsNotOtherwiseReflectedInFairValueOrTotalCompensationMember fibk:JamesReuterMember 2025-01-01 2025-12-31 0000860413 fibk:ValueOfDividendsOrOtherEarningsPaidOnStockOrOptionAwardsNotOtherwiseReflectedInFairValueOrTotalCompensationMember 2025-01-01 2025-12-31 0000860413 1 2025-01-01 2025-12-31 0000860413 2 2025-01-01 2025-12-31 0000860413 3 2025-01-01 2025-12-31 0000860413 4 2025-01-01 2025-12-31 0000860413 5 2025-01-01 2025-12-31 iso4217:USD false 0000860413 PRE 14A FIRST INTERSTATE BANCSYSTEM, INC. true <span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">Equity awards are generally granted to our NEOs on March 15th of the applicable fiscal year. In certain </span><div style="font-size:12pt;line-height:11pt;position:var(--position);top:73.05pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">circumstances, including the hiring or promotion of an officer, the Compensation Committee may </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:85.15pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">approve grants to be effective at other times. </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:102.25pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">The Company does not currently grant awards of stock options, stock appreciation rights, or similar </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:114.35pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">option-like awards as part of its compensation program. The Company does not time the disclosure of </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:126.45pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">material non-public information, or the granting of equity awards, for the purpose of impacting the </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:138.55pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">value of executive compensation.</span></div> 0 0 4615009 4684633 1126764 1155714 112.10 152.72 302100000 12.16 4870569 4324053 2540806 2689115 1278512 1234476 98.91 143.40 226000000.0 11.54 3384896 1951042 0 0 835999 550266 87.57 126.67 257500000 15.23 4617084 4215324 0 0 1482037 1343374 102.77 127.18 202200000 16.22 3201243 2342207 0 0 928135 733189 103.59 136.65 192100000 16.35 James A. Reuter Kevin P. Riley James A. Reuter Kevin P. Riley 4615009 1126764 -2534832 -353422 2986326 416376 -381870 -16109 0 0 0 -17895 0 0 0 4684633 1155714 <span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">In the Company’s assessment, the most important financial performance measures used to link </span><div style="font-size:12pt;line-height:11pt;position:var(--position);top:73.05pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">compensation actually paid to our NEOs, for the most recently completed fiscal year, to the Company’s </span></div><div style="font-size:12pt;line-height:11pt;position:var(--position);top:85.15pt;width:612pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:11pt;font-style:normal;font-weight:normal;left:49.5pt;position:var(--position);text-decoration:none;white-space:pre">performance were:</span></div><div style="position:var(--position);top:102.25pt;width:612pt"><div style="font-size:0pt;left:49.5pt;position:var(--position);width:416.25pt"><div><table style="border-collapse:collapse;display:inline-table;width:100%"><tbody><tr style="height:0"><td style="padding:0;width:416.25pt"></td></tr><tr style="height:15pt"><td style="font-size:0;text-align:left;vertical-align:top"><div style="position:var(--position);width:416.25pt"><div><div style="line-height:10pt;position:var(--position);top:3.91pt;width:416.25pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:20.630000000000003pt;position:var(--position);text-decoration:none;white-space:pre">•</span><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:38.63pt;position:var(--position);text-decoration:none;white-space:pre">Total Shareholder Return</span></div></div></div></td></tr><tr style="height:15pt"><td style="font-size:0;text-align:left;vertical-align:top"><div style="position:var(--position);top:15pt;width:416.25pt"><div><div style="line-height:10pt;position:var(--position);top:3.91pt;width:416.25pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:20.630000000000003pt;position:var(--position);text-decoration:none;white-space:pre">•</span><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:38.63pt;position:var(--position);text-decoration:none;white-space:pre">Core Return on Average Tangible Common Equity</span></div></div></div></td></tr><tr style="height:15pt"><td style="font-size:0;text-align:left;vertical-align:top"><div style="position:var(--position);top:30pt;width:416.25pt"><div><div style="line-height:10pt;position:var(--position);top:3.91pt;width:416.25pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:20.630000000000003pt;position:var(--position);text-decoration:none;white-space:pre">•</span><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:38.63pt;position:var(--position);text-decoration:none;white-space:pre">Adjusted PPNR per Share</span></div></div></div></td></tr><tr style="height:15pt"><td style="font-size:0;text-align:left;vertical-align:top"><div style="position:var(--position);top:45pt;width:416.25pt"><div><div style="line-height:10pt;position:var(--position);top:3.91pt;width:416.25pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:20.630000000000003pt;position:var(--position);text-decoration:none;white-space:pre">•</span><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:38.63pt;position:var(--position);text-decoration:none;white-space:pre">Adjusted Efficiency Ratio</span></div></div></div></td></tr><tr style="height:15pt"><td style="font-size:0;text-align:left;vertical-align:top"><div style="position:var(--position);top:60pt;width:416.25pt"><div><div style="line-height:10pt;position:var(--position);top:3.91pt;width:416.25pt"><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:20.630000000000003pt;position:var(--position);text-decoration:none;white-space:pre">•</span><span style="color:#42454d;font-family:'Trebuchet MS', sans-serif;font-size:10pt;font-style:normal;font-weight:normal;left:38.63pt;position:var(--position);text-decoration:none;white-space:pre">Non-Performing Assets/Total Assets</span></div></div></div></td></tr></tbody></table></div></div></div> •Total Shareholder Return •Core Return on Average Tangible Common Equity •Adjusted PPNR per Share •Adjusted Efficiency Ratio •Non-Performing Assets/Total Assets <div style="left:109.12pt;position:var(--position)"><div style="position:var(--position)"><img alt="3439" id="i-39" src="fibk-20260330_g39.gif" style="height:225pt;width:393.75pt"/></div></div> <div style="left:109.12pt;position:var(--position)"><div style="position:var(--position)"><img alt="3441" id="i-40" src="fibk-20260330_g40.gif" style="height:225pt;width:393.75pt"/></div></div> <div style="left:109.12pt;position:var(--position)"><div style="position:var(--position)"><img alt="3443" id="i-41" src="fibk-20260330_g41.gif" style="height:225pt;width:393.75pt"/></div></div>