SCHEDULE: Wellington Management Discloses 5.6% Stake in First Interstate

Wellington Management Group LLP and its affiliates have reported a 5.6% beneficial ownership stake in First Interstate BancSystem, Inc. as of September 30, 2025.

Summary

• Wellington Management Group LLP, along with its affiliates Wellington Group Holdings LLP, Wellington Investment Advisors Holdings LLP, and Wellington Management Company LLP, jointly reported beneficial ownership of 5,915,425 shares of First Interstate BancSystem, Inc. common stock.
• This aggregate ownership represents 5.6% of the issuer's common stock.
• The reporting entities collectively hold shared voting power over 5,358,835 shares and shared dispositive power over 5,915,425 shares.
• The securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing the control of First Interstate BancSystem, Inc.
• The beneficial ownership is held on behalf of clients of the Wellington Investment Advisers, with no single client known to have such right or power with respect to more than five percent of this class of securities.

Sentiment

Score: 5

Explanation: A Schedule 13G filing is a routine disclosure of beneficial ownership and typically carries a neutral sentiment. It indicates an institutional investor has crossed a 5% ownership threshold but does not inherently convey positive or negative news about the issuer's performance or prospects.

Future Outlook

The filing does not contain any forward-looking statements or guidance regarding the issuer's future performance or the reporting person's future investment intentions beyond the statement that the shares are held in the ordinary course of business.

Industry Context

This filing indicates a significant institutional investment in First Interstate BancSystem, Inc., a regional bank. Large institutional holdings like this are common in the financial services sector, reflecting investor confidence or strategic allocation within diversified portfolios. Wellington Management is a major global asset manager, and its stake suggests a belief in the long-term value or stability of First Interstate BancSystem within the banking industry.

Stakeholder Impact

• Shareholders: Increased institutional ownership can sometimes be viewed positively, signaling confidence from a major asset manager. It also means a significant block of shares is held by a single entity, which could influence future voting matters.
• Management: Awareness of a significant institutional shareholder may influence management's strategic decisions, though Wellington Management states no intent to influence control.

Key Dates

Keywords

First Interstate BancSystem, Wellington Management, Schedule 13G, Beneficial Ownership, Common Stock, Institutional Investor, Bank Stock, Financial Services