CBS Radio, Inc., formerly known as Infinity Broadcasting Corporation, is one of the largest owners and operators of radio stations in the United States, fifth behind main rivals iHeartMedia (previously Clear Channel Communications, which owns many of the stations that were previously owned by former CBS parent Viacom before 1997), Cumulus Media, Townsquare Media, and Alpha Media. CBS Radio owns and operates 117 radio stations across the country. It is currently part of CBS Corporation, which also owns the CBS radio and television networks, and jointly owns The CW. CBS Radio is one of the oldest units within CBS Corporation, and has been around since 1928. However, the actual CBS Radio Network (now CBS Radio News) was launched in 1927, when CBS itself was known as United Independent Broadcasters. Columbia Records later joined in and that company was renamed the Columbia Phonographic Broadcasting System. In September 1927, Columbia Records sold the company to William S. Paley and in 1928, Paley streamlined the corporate name to Columbia Broadcasting System. The company that would become CBS Radio was founded in 1972 as Infinity Broadcasting Corporation by Michael A. Wiener and Gerald Carrus, with the acquisition of KOME, an FM radio station that served the San Francisco Bay Area. It became a publicly traded company twice, in 1986, and again in 1992.