The company was established in 1983 as Showtime/The Movie Channel, Inc. after Viacom and Warner-Amex Satellite Entertainment (now Viacom Media Networks) merged their premium channels, Showtime and The Movie Channel respectively, into one division. In 1984, American Express sold their interest in Warner-Amex to Warner Communications (now Time Warner) making Warner the new half-owner of Showtime/TMC. In 1985, Warner sold its half-interest to Viacom, making the company a wholly owned subsidiary of Viacom. In 1988, the company was renamed Showtime Networks Inc.
SNI, along with CBS, The CW Television Network (formerly UPN), Viacom Outdoor, Spelling Television, CBS Television Studios (formerly CBS Productions, Paramount Television and CBS Paramount Television), CBS Television Distribution (formerly Paramount Domestic Television, CBS Paramount Domestic Television and King World), CBS Studios International (formerly CBS Paramount International Television), Simon & Schuster and other entities became part of CBS Corporation when CBS officially split from Viacom in December 2005. SNI managed the CBS, Robert Redford and NBC Universal joint venture Sundance Channel until 2008, when it was sold to Rainbow Media (now AMC Networks).
Year in parentheses denotes when each network and channel was brought into the SNI fold.
1Channel created by Warner-Amex Satellite Entertainment prior to 1983.
2Co-owned with the Smithsonian Institution. Showtime Networks handles operations; is supported through commercial advertising.
SNI won a Peabody Award in 2002 for Bang Bang You're Dead. In 2008, SNI was honored at the 59th Annual Technology & Engineering Emmy Awards for Outstanding Achievement in Advanced Media Technology for Best Use of Commercial Advertising on Personal Computer for the companion website to the series The L Word.