Due to the ratio of U.S. and Mexican-licensed stations, San Diego is the largest media market in the United States that is legally unable to support a television station duopoly between two full-power stations under FCC regulations, which disallow duopolies in metropolitan areas with fewer than nine full-power television stations and require that there must be eight unique station owners that remain once a duopoly is formed (there are only seven full-power stations on the California side of the San Diego-Tijuana market).
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