MGE Energy, Inc. is a holding company. The Company operates through its subsidiaries and generates and distributes electric energy and distributes natural gas. It operates in five segments: Regulated electric utility operations, Regulated gas utility operations, Nonregulated energy operations, Transmission investments and All other. The Regulated electric utility operations segment distributes electricity in a service area covering a 316 square-mile area of Dane County, Wisconsin. The Regulated gas utility operations segment comprises transportation and distribution of natural gas in a service area covering 1,678 square miles in seven south-central Wisconsin counties. The Nonregulated energy operations segment comprises development of generation sources. The Transmission Investments segment comprises owning and operating electric transmission facilities primarily in Wisconsin. The All other segment comprises investing in companies and property that relate to the regulated operations.