In the broadcasting industry, a network affiliate is a local broadcaster which carries some or all of the programme line-up of a television or radio network, but is owned by a company other than the owner of the network. This distinguishes such a station from an owned-and-operated station (O&O), which is owned by its parent network.
In the United States, Federal Communications Commission (FCC) regulations limit the number of network-owned stations as a percentage of total market size. As such, networks tend to have O&Os only in the largest media markets, and rely on affiliates to carry their programming in other markets. However, even the largest markets may have network affiliates in lieu of O&Os. For instance, Tribune Broadcasting's WPIX serves as the New York City affiliate for the CW Television Network, which does not have an O&O in that market. On the other hand, several other TV stations in the same market — WABC (ABC), WCBS (CBS), WNBC (NBC), WNYW (Fox) and WWOR (MyNetworkTV) — are O&Os.
In Canada, the Canadian Radio-Television and Telecommunications Commission (CRTC) has significantly more lenient rules regarding media ownership. As such, most television stations, regardless of market size, are now O&Os of their respective networks, with only a few true affiliates remaining. The Canadian Broadcasting Corporation originally relied on a large number of privately-owned affiliates to disseminate its radio and television programming. However, since the 1960s, most of the CBC Television affiliates have been replaced by network owned and operated stations or retransmitters. CBC Radio stations are now entirely O&O.
While network-owned stations will normally carry the full programming schedule of the originating network, an affiliate is independently-owned and typically under no obligation to do so. Affiliated stations often buy supplementary programming from another source, such as a syndicator or another television network which does not have coverage in the station's broadcast area, in addition to the programming they carry from their primary network affiliation.