MDU RESOURCES GROUP INC

Note 1 -Basis of presentation

The accompanying consolidated interim financial statements were prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with those appearing in the 2025 Annual Report. The information is unaudited but includes all adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Depreciation and amortization expense is reported separately on the Consolidated Statements of Income and therefore is excluded from the other line items within operating expenses.

Discontinued operations includes certain costs associated with legacy business activities other than certain general and administrative costs (reflected in operation and maintenance expense) and interest expense, which were previously allocated to the Company's former businesses which do not meet the criteria for discontinued operations. Discontinued operations are not material to the financial statements for any period presented. Unless otherwise indicated, the amounts presented in the accompanying condensed notes to the consolidated financial statements relate to the Company's continuing operations. For more information on discontinued operations, see Note 3.

Management has also evaluated the impact of events occurring after March 31, 2026, up to the date of issuance of these consolidated interim financial statements on May 7, 2026, that would require recognition or disclosure in the Consolidated Financial Statements.