CBS Radio (first era)
In 1997, CBS Radio filed an initial public offering of stock. The company was renamed Infinity Radio as a result. The name "Infinity" came from a company acquired by Westinghouse (which in 1995 purchased CBS) in 1996, the Infinity Broadcasting Corporation. CBS Corporation would hold 81.8% of the new company.
CBS Radio (second era)
Upon the start of the new year 2006, Viacom (which has purchased CBS in 2000, and had bought out Infinity in February of 2001) was split into two companies: a new Viacom and CBS Corporation. In preparation of the split, in December 2005, Viacom reverted Infinity Radio back to the CBS Radio name. CBS Radio is now part of CBS Corp., although Infinity Broadcasting Corp. continues to be incorporated within CBS.
On February 2, 2017, CBS Radio has agreed to be acquired by Entercom Communications. The Federal Communications Commission approved the merger on November 9th and the transaction closed on November 17th.