MDU RESOURCES GROUP INC

Note 13 -Debt

Certain debt instruments of the Company and its subsidiaries contain restrictive and financial covenants and cross-default provisions. In order to borrow under the respective debt agreements, the Company and its subsidiaries must be in compliance with the applicable covenants and certain other conditions. The Company and its subsidiaries were in compliance with applicable covenants at September 30, 2026. In the event the Company or its subsidiaries do not comply with the applicable covenants and other conditions, alternative sources of funding may need to be pursued.

Credit facilities

Montana-Dakota's commercial paper program is supported by a revolving credit agreement. While the amount of commercial paper outstanding does not reduce available capacity under the revolving credit agreement, Montana-Dakota does not issue commercial paper in an aggregate amount exceeding the available capacity under the credit agreement. The Company's borrowings under the commercial paper program and revolving credit agreements are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued borrowings. All of the credit agreements contain customary covenants and provisions, including covenants not to permit, as of the end of any fiscal quarter, the ratio of funded debt to total capitalization (determined on a consolidated basis) to be greater than 65 percent. Other covenants include restrictions on the sale of certain assets, limitations on indebtedness and the making of certain investments.

The following table summarizes the outstanding revolving credit facilities of the Company and its subsidiaries:

Index

Long-term Debt Outstanding

Long-term debt outstanding was as follows:

Montana-Dakota On October 28, 2025, Montana-Dakota entered into a NPA to issue $250.0 million of senior notes, with maturity dates of October 28, 2035, October 28, 2040, and February 2, 2056, at a weighted average interest rate of 5.96 percent. On October 28, 2025, Montana-Dakota issued $150.0 million in senior notes under the NPA with the remaining $100.0 million issued on February 2, 2026. The agreement contains customary covenants and provisions, including a covenant of Montana-Dakota not to permit, at any time, the ratio of total debt to capitalization to be greater than 65 percent. Other covenants include a minimum interest coverage ratio and restrictions on the sale of certain assets.

On December 30, 2025, Montana-Dakota entered into a $250.0 million term loan agreement with a SOFR-based variable interest rate and a maturity date of January 29, 2027. In 2026, Montana-Dakota paid down the $250.0 million outstanding balance under the term loan agreement. The term loan was terminated upon pay-off.

On June 16, 2026, Montana-Dakota entered into a NPA to issue $225.0 million of senior notes, with a maturity date of August 18, 2057, at an interest rate of 6.17 percent. The $225.0 million was issued on August 18, 2026. The agreement contains customary covenants and provisions, including a covenant of Montana-Dakota not to permit, at any time, the ratio of total debt to capitalization to be greater than 65 percent. Other covenants include a minimum interest coverage ratio and restrictions on the sale of certain assets.

Intermountain On September 22, 2026, Intermountain entered into a NPA to issue $60.0 million of senior notes, with a maturity date of September 22, 2036, at an interest rate of 5.90 percent. The agreement contains customary covenants and provisions, including a covenant of Intermountain not to permit, at any time, the ratio of total debt to capitalization to be greater than 65 percent. Other covenants include minimum interest coverage ratio and restrictions on the sale of certain assets.

Cascade On August 24, 2026, Cascade entered into a NPA to issue $100.0 million of senior notes, with maturity dates of August 24, 2036, and August 24, 2046, at a weighted average interest rate of 5.96 percent. The agreement contains customary covenants and provisions, including a covenant of Cascade not to permit, at any time, the ratio of total debt to capitalization to be greater than 65 percent. Other covenants include minimum interest coverage ratio and restrictions on the sale of certain assets.

WBI Energy Transmission On January 15, 2026, WBI Energy Transmission extended its $350.0 million uncommitted note purchase and private shelf agreement from December 22, 2025 to December 22, 2028, unless either party terminates such issuance right. WBI Energy Transmission had $235.0 million of notes outstanding at September 30, 2026, which reduced the remaining capacity under this uncommitted private shelf agreement to $115.0 million. The principal amount and interest rate of any series of shelf notes will be determined at the applicable time of issuance and purchase.

WBI Energy Transmission's ratio of total debt to total capitalization at September 30, 2026 was 39 percent.