WELLINGTON MANAGEMENT GROUP LLP - 30 Sep 2025 SCHEDULE 13G Report for First Interstate BancSystem, Inc. Common Stock (FIBK)

Filing Manager
WELLINGTON MANAGEMENT GROUP LLP
Reporting Manager
Wellington Management Group LLP
Security
First Interstate BancSystem, Inc. Common Stock
Symbol
FIBK
Shares outstanding
105,632,589 shares
Disclosed Ownership
5,915,425 shares
Ownership
5.6%
Form type
SCHEDULE 13G
Filing time
12 Nov 2025, 09:33:33 UTC
Date of event
30 Sep 2025
SEC
View on sec.gov

Reporting Managers (4)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
Wellington Management Group LLP 5.6% 5,915,425 0 5,358,835 Taisia Lowe Regulatory Analyst
Wellington Group Holdings LLP 5.6% 5,915,425 0 5,358,835 Taisia Lowe Regulatory Analyst
Wellington Investment Advisors Holdings LLP 5.6% 5,915,425 0 5,358,835 Taisia Lowe Regulatory Analyst
Wellington Management Company LLP 5.4% 5,915,425 0 5,319,204 Taisia Lowe Regulatory Analyst