Other Events. On August 21, 2026, MGE Energy, Inc. (the Company) issued a press release announcing an increase in its regular quarterly dividend on its outstanding shares of common stock. The release announced the declaration of a quarterly dividend of $0.5083 per share, payable on September 15, 2026, to shareholders of record as of September 1, 2026. The Company is filing a copy of that press release as Exhibit 99.1 to this report.

Results of Operations and Financial Condition. On August 5, 2026, MGE Energy, Inc. (the Company) issued a press release announcing its second quarter 2026 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither registr…

Vice President – Energy Operations — James J. Lorenz: Mr. Lorenz is retiring and will be succeeded by John T. Robson.

Other Events. On May 6, 2026, MGE Energy, Inc. (the “Company”) entered into an Underwriting Agreement (the “Underwriting Agreement”) with Morgan Stanley & Co. LLC, Guggenheim Securities, LLC, BofA Securities, Inc. and J.P. Morgan Securities LLC, as underwriters (collectively, the “Underwriters”), and Morgan Stanley & Co. LLC, BofA Securities, Inc. and J.P. Morgan Securities LLC, acting in their capacity as forward sellers (in such capacity, the “Forward Sellers”), in connection with the under…

Entry into a Material Definitive Agreement. The disclosure regarding the Forward Sale Agreements (as defined below) under

Results of Operations and Financial Condition. On May 5, 2026, MGE Energy, Inc. (the Company) issued a press release announcing its first quarter 2026 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither registrant…

Executive Vice President – Chief Financial Officer and Treasurer — Jared Bushek: Mr. Bushek was promoted to a higher executive position within the company.

Results of Operations and Financial Condition. On February 24, 2026, MGE Energy, Inc. (the Company) issued a press release announcing its fourth quarter and full year 2025 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf…

Other Events. On February 24, 2026, MGE Energy, Inc. (the “Company”) entered into an Equity Distribution Agreement (the “Equity Distribution Agreement”) with Guggenheim Securities, LLC and Morgan Stanley & Co. LLC, as sales agents and/or principals (each a “Manager”, and collectively, the “Managers”). Pursuant to the Equity Distribution Agreement, the Company may offer and sell from time to time, shares of the Company’s common stock, par value $1.00 per share, having an aggregate gross sales…

Termination of a Material Definitive Agreement. On January 27, 2026, Madison Gas and Electric Company (“MGE”), satisfied and discharged its Indenture of Mortgage and Deed of Trust, dated as of January 1, 1946 (as amended and supplemented, the “Indenture”), between MGE and U.S. Bank Trust Company, National Association, as successor trustee (the “Trustee”). The Indenture had created a lien on, and security interest in, MGE’s utility plant assets. On January 27, 2026, MGE completed a redemption…

Entry into a Material Definitive Agreement. On January 22, 2026, Madison Gas and Electric Company ("MGE"), a wholly-owned subsidiary of MGE Energy, Inc., entered into a Note Purchase Agreement dated January 22, 2026 (the "Note Purchase Agreement"), with the note purchasers named therein, pursuant to which MGE issued $30 million in principal amount of its 5.05% Senior Notes, Series A, due January 31, 2036 (the "Series A Notes"), $30 million in principal amount of its 5.25% Senior Notes, Series…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. On January 22, 2026, MGE issued $90 million in aggregate principal amount of the Notes pursuant to the Note Purchase Agreement. The Notes are unsecured and are not issued under, or governed by, MGE’s Indenture dated as of September 1, 1998, which governs MGE’s Medium-Term Notes. MGE expects to use the net proceeds from the sale of the Notes to cover capital expenditures and other…

Results of Operations and Financial Condition. On November 5, 2025, MGE Energy, Inc. (the Company) issued a press release announcing its third quarter 2025 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither regist…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. On October 14, 2025, MGE entered into the Note Purchase Agreement providing for the issuance of $25 million in principal amount of its 5.12% Senior Notes, Series A, due November 15, 2036, and $25 million in principal amount of its 5.76% Senior Notes, Series B, due November 15, 2055, at a closing scheduled for November 13, 2025. The Notes will be unsecured and will not be issued u…

Entry into a Material Definitive Agreement. On October 14, 2025, Madison Gas and Electric Company (MGE), a wholly-owned subsidiary of MGE Energy, Inc., entered into a Note Purchase Agreement dated October 14, 2025 (the Note Purchase Agreement), with the note purchasers named therein, in which it committed to issue $25 million in principal amount of its 5.12% Senior Notes, Series A, due November 15, 2036 (the Series A Notes), and $25 million in principal amount of its 5.76% Senior Notes, Serie…

Other Events. On August 15, 2025, MGE Energy, Inc. (the Company) issued a press release announcing an increase in its regular quarterly dividend on its outstanding shares of common stock. The release announced the declaration of a quarterly dividend of $0.475 per share, payable on September 15, 2025, to shareholders of record as of September 1, 2025. The Company is filing a copy of that press release as Exhibit 99.1 to this report.

Results of Operations and Financial Condition. On August 6, 2025, MGE Energy, Inc. (the Company) issued a press release announcing its second quarter 2025 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither registr…

Results of Operations and Financial Condition. On May 7, 2025, MGE Energy, Inc. (the Company) issued a press release announcing its first quarter 2025 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither registrant…

Executive Vice President — Lynn Hobbie: The filing discloses a planned retirement of a senior executive (EVP) by the end of the year, which is an orderly succession rather than a sudden loss or shock.

Results of Operations and Financial Condition. On February 25, 2025, MGE Energy, Inc. (the Company) issued a press release announcing its fourth quarter and full year 2024 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf…

Regulation FD Disclosure. On December 4, 2024, Madison Gas and Electric Company (MGE), Alliant Energy Corporation, and Wisconsin Public Service Corp. announced plans to shift the suspension of coal operations to the end of 2029 at their jointly-owned Columbia Energy Center in Portage, Wisconsin. This shift from the previous date of 2026 is intended to provide the companies time to explore converting at least one of Columbia’s units to natural gas before the end of 2029. MGE has a 19% ownershi…

Results of Operations and Financial Condition. On November 6, 2024, MGE Energy, Inc. (the Company) issued a press release announcing its third quarter 2024 earnings. The Company is furnishing a copy of that press release as Exhibit 99.1 to this report. This combined Form 8-K is being furnished separately by the Company and Madison Gas and Electric Company. Information contained herein relating to any individual registrant has been furnished by such registrant on its own behalf. Neither regist…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. On October 31, 2024, MGE entered into the Note Purchase Agreement providing for the issuance of $25 million in principal amount of its 5.30% senior notes, Series A, due December 1, 2039, and $25 million in principal amount of its 5.59% senior notes, Series B, due December 1, 2054, at a closing scheduled for December 4, 2024. The notes will be unsecured and will not be issued unde…

Entry into a Material Definitive Agreement. On October 31, 2024, Madison Gas and Electric Company (MGE), a wholly-owned subsidiary of MGE Energy, Inc., entered into a Note Purchase Agreement dated October 31, 2024 (the Note Purchase Agreement), with the note purchasers named therein, in which it committed to issue $25 million in principal amount of its 5.30% senior notes, Series A, due December 1, 2039, and $25 million in principal amount of its 5.59% senior notes, Series B, due December 1, 2…

Other Events. On August 16, 2024, MGE Energy, Inc. (the Company) issued a press release announcing an increase in its regular quarterly dividend on its outstanding shares of common stock. The release announced the declaration of a quarterly dividend of $0.45 per share, payable on September 15, 2024, to shareholders of record as of September 1, 2024. The Company is filing a copy of that press release as Exhibit 99.1 to this report.