PNM Resources, Inc., through its subsidiaries, provides electricity and electric services in the United States. It operates through Public Service Company of New Mexico (PNM) and Texas-New Mexico Power Company (TNMP) segments. The PNM segment engages in the generation, transmission, and distribution of electricity. It generates electricity using coal, natural gas and oil, nuclear fuel, solar, wind, and geothermal energy sources. As of December 31, 2020, this segment had owned or leased facilities with a total net generation capacity of 2,168 megawatts; and owned 3,389 miles of electric transmission lines, 6,077 miles of distribution overhead lines, 5,962 miles of underground distribution lines, and 255 substations. It also owns and leases office and other equipment, office space, vehicles, and real estate. The TNMP segment provides regulated transmission and distribution services. As of December 31, 2020, this segment owned 983 miles of overhead electric transmission lines, 7,282 miles of overhead distribution lines, 1,348 miles of underground distribution lines, and 110 substations. It also owns and leases vehicles, service facilities, and office locations throughout its service territory. The company serves approximately 800,000 homes and businesses in New Mexico and Texas. PNM Resources, Inc. was incorporated in 1917 and is headquartered in Albuquerque, New Mexico.