Continued sales and mergers in the TV industry often involve divestitures and other changes to comply with ownership rules. Here’s a summary of some of the regulations and terms used as of early 2021:

Top four: A company that owns a full-power TV station ranked in the top four in a market cannot buy a second full-power TV station ranked in the top four in the same market. Historically, the top four stations in any given market were typically the ABC, CBS, FOX, and NBC affiliates. However, this may no longer be the case in markets where one of the “big four” networks has been moved to a subchannel or a low-power TV station (see below). Companies have also gotten around this rule by using shared services agreements in which they do not formally buy a station but provide its programming and advertising.

Full-power and low-power are classes of TV stations under FCC licensing. FCC ownership regulations only cover full-power licenses; ownership of low-power TV licenses is not regulated no matter what network they carry. Full-power TV stations may have suffixes of -TV or -DT (or no suffix at all). Low-power TV stations have suffixes of -LP or -LD, or an alphanumeric callsign such as K39ZZ.

Subchannels are considered to be part of the same license as the primary channel. For example, if a station’s DT1 channel carries ABC and its DT2 carries FOX, both are considered to be part of the same FCC license. (When the ratings for each station in a market are computed for regulatory purposes, the ratings for each channel on each station are added up to determine each station’s overall rating.)

virtual channel is the channel displayed for a station on over-the-air TV receivers, which usually does not match the RF channel (frequency) on which the station actually broadcasts. Virtual channels can be swapped between stations, so companies have sometimes divested a full-power license but retained its heritage virtual channel number (and callsign) on a low-power station. Cable channel assignments are sometimes also traded this way in hopes that viewers will not notice that the affiliation moved to a different station.

Eight voices: A provision in the rules says there cannot be a full-power TV duopoly formed or transferred if it will result in fewer than eight owners of full-power TV stations in the Designated Market Area. Non-commercial stations and standalone stations in outlying areas of a market, such as Appleton and Bemidji in the Minneapolis market, count towards this figure. The FCC had dropped this rule several years ago but a court ruling brought it back to life; the rule may be dropped again in the future.

failing station waiver is a request that the FCC waive the eight voices rule because the station to be sold has low ratings, low revenue, and no other prospective buyers and that the combination would serve the public interest. Buyers often also argue that the station has no prospect of obtaining a major network affiliation.

Designated Market Areas are defined by Nielsen Media based on viewership data. Typically, a county is assigned to a market based on which market’s stations people in that county watch the most. Each location is in one and only one DMA. County lines serve as the boundaries in most cases, but there are a few rare cases in which a county is divided between two markets, such as Nicollet County, Minnesota. Some DMA’s are only one county while others cover an entire state.

satellite station is a full-power station that fully repeats another station’s programming to expand its reach across the market. Translators are similar, except they use low-power transmitters. Satellite stations and translators do not count towards ownership rules.

The national ownership cap is 39% of TV households. A full-power station transmitting on a VHF frequency is assumed to reach all of the households in its market regardless of its actual coverage area.

The UHF Discount cuts the number of households in a UHF station’s market in half for regulatory purposes. (A UHF station is one transmitting on a UHF frequency, RF channels 14-36, even if its virtual channel is 2-13.) This provision was developed in the era of analog TV when the reach of UHF signals was inferior to VHF. The rule remains on the books even though UHF has proven to be the superior band for digital TV broadcasting.