Like Fox (then owned by 20th Century Fox's parent company at the time, News Corporation), the two networks had been joint ventures between major Hollywood studios and large owners of previously independent stations: The WB was owned by the Warner Bros. Entertainment division of Time Warner, in a joint venture with the Tribune Company, and UPN was founded by Chris-Craft Industries, in a programming partnership with Paramount Pictures.
Over the course of 11½ seasons, despite a number of minor-hit or cult-hit series such as Star Trek: Voyager, Star Trek: Enterprise, Charmed, 7th Heaven, Gilmore Girls, Girlfriends, Buffy the Vampire Slayer, Felicity, Moesha, Dawson's Creek, The Parkers, One on One, Roswell, and Kids' WB's airing of the anime Pokémon, neither network was able to attain the stature that Fox had gained in its first decade, much less that of the longstanding "Big Three" television networks (ABC, CBS and NBC).
Viacom was permitted to keep interests in both networks, in effect, resulting in the Federal Communications Commission (FCC) lifting its long-standing ban on television station duopolies.
[11][12][13] This had the adverse effect of making UPN one of the few networks not to have owned-and-operated flagship stations in New York City and Los Angeles.
[24] The rumors proved true, and on February 22, 2006, Fox announced the launch of its own network, MyNetworkTV, a programming service meant to fill the two nightly primetime hours that would open up on its UPN and WB-affiliated stations after the start of The CW.
In Honolulu, Hawaii, The CW did not become available in the market until early December 2006, where it was carried on a digital subchannel of local Fox affiliate KHON-TV.
Sinclair signed deals to carry the networks in early May, despite reservations with The CW and MyNetworkTV reporting demands for reverse compensation.
[34] While WGN-TV in Chicago became a charter affiliate of The CW, its former national counterpart WGN America never aired programs from The CW through a formal affiliation when it operated as WGN-TV's out-of-market superstation feed prior to December 2014 (although it did carry reruns of select CW series in marathon form in 2013), as the network has enough affiliate coverage that The CW did not need to use the national WGN feed to carry its programming; WGN America had previously carried WB programming from that network's January 1995 launch until October 1999, when Tribune Broadcasting and Time Warner mutually decided that The WB's national broadcast coverage had increased to a level that allowed the WGN national feed to discontinue carrying the network.
[1][35][36] Several affiliates changed their call letters to reflect their new CW and MyNetworkTV affiliations; e.g., KPWB-TV in Des Moines became KCWI, WNPA-TV in Pittsburgh became WPCW, WJWB in Jacksonville became WCWJ, WHCP in Portsmouth, Ohio became WQCW, WEWB in Albany, New York became WCWN, KWCV in Wichita, Kansas became KSCW, WBDC in Washington, D.C. became WDCW, KBHK in San Francisco became KBCW, KHWB in Houston became KHCW.
Some stations retained call signs that referred to UPN and The WB, such as WUPA in Atlanta and KWBA-TV in Tucson, Arizona, respectively.
Due to the availability of "instant duopoly" digital subchannels, and the overall lack of a need to settle for a secondary affiliation with shows aired in problematic timeslots, both The CW and MyNetworkTV launched with far greater national coverage than that enjoyed by UPN and The WB when they started in 1995.
Given the merger of the two networks to create The CW (as well as the eventual launch of MyNetworkTV and the proliferation of digital subchannels), the scope of the realignment caused the largest single shakeup in American broadcast television since the Fox/New World Communications alliance of 1994, which preceded the subsequent launches of UPN and The WB the following year that drastically reduced the number of independent television stations in the U.S., some of which had been marketed and distributed as superstations as recently as the mid-1990s.
Additionally, MyNetworkTV signed with three Tribune stations that did not take the CW affiliation: WPHL in Philadelphia, WATL in Atlanta and KTWB in Seattle.
As a consequence, in three of the top 10 media markets – Boston, Dallas/Fort Worth and San Francisco – programs from The WB, UPN and MyNetworkTV were all available to viewers from September 5 to 17.
These markets included Cincinnati, Honolulu, Charleston, South Carolina, El Paso, Corpus Christi, Palm Springs and Lima, Ohio.
[44] Before the merger, Granite Broadcasting Corporation agreed to sell KBWB and WDWB to AM Media, a unit of private equity firm ACON Investments; as The CW affiliated with KBCW and WKBD, respectively, the Granite-AM Media deal collapsed, prompting Granite to sue CBS and Time Warner over the failed deal.
[46] UPN quietly ceased operations on September 15, 2006, by fading to black after its usual airing of WWE Friday Night SmackDown!
Because of this, UPN was entirely unavailable for its final two weeks in those markets; as a result, SmackDown was on several Tribune-owned charter CW affiliates, including WPIX, KTLA, and WGN, per an earlier arrangement with the WWE.
[47][48] The WB closed on September 17 with The Night of Favorites and Farewells, a five-hour block of pilot episodes of the network's past signature series, including Felicity, Angel, Buffy the Vampire Slayer and Dawson's Creek.
[51] After launching, The CW usually finished fifth in the Nielsen ratings and even fell behind Spanish-language network Univision at times.
[55][56][57][58] The CW's ratings struggles eventually subsided in later years: the network beat NBC for the first time in the key 18–49 demographic for a single calendar night on November 21, 2013.
[65] Nexstar Media Group, which acquired Tribune Media in 2019 after a prior failed merger attempt with Sinclair Broadcast Group,[66] assumed operations of The CW on August 15, 2022,[67] and acquired a 75-percent ownership stake in The CW on October 3, 2022; former joint owners Paramount Global (successor to CBS Corporation) and Warner Bros.