Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

MGE Energy, Inc. ☐ Madison Gas and Electric Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

MGE Energy, Inc. ☐ Madison Gas and Electric Company ☐

Item 7.01. 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% ownership interest in Columbia. A copy of the joint press release is furnished as Exhibit 99.1 to this report.

The information in this Item (including Exhibit 99.1) shall not be deemed “filed;” nor shall it be deemed incorporated by reference in any filing under the securities laws except as shall be expressly set forth in such a filing.

Forward-Looking Statements

This report contains forward-looking statements that reflect management’s current assumptions and estimates -- especially as they relate to plant unit retirement dates. These forward-looking statements are made pursuant to the provisions of the Private Securities Litigation Reform Act of 1995. Words such as “believe,” “expect,” “anticipate,” “estimate,” “could,” “should,” “intend,” “plan,” “will,” “project” and other similar words generally identify forward-looking statements. We caution investors that these forward-looking statements are subject to known and unknown risks and uncertainties that may cause actual results to differ materially from those projected, expressed, or implied. The factors that could cause actual results to differ materially from the forward-looking statements made by the Registrants include those factors discussed herein, as well as the items discussed in ITEM 1A. Risk Factors in the Registrants’ annual report on Form 10-K for the year ended December 31, 2023, and other factors discussed in filings made by the Registrants with the SEC. Readers are cautioned not to place undue reliance on these forward-looking statements, which apply only as of the date of this report. The Registrants do not undertake any obligation to publicly release any revision to their forward-looking statements to reflect events or circumstances after the date of this report.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrants have duly caused this report to be signed on their behalf by the undersigned hereunto duly authorized.