When the United States began buying back licenses in a broadcast spectrum auction in 2017, it also allowed companies that had a duopoly in a market to sell one of the licenses but continue to use the virtual channel of the sold channel on a subchannel of the other. For example, Sunbeam Television sold WLVI in the auction, but in turn was allowed to use its virtual channel 56 on WHDH, which uses virtual channel 7 for its main channel; thus, the WHDH license uses both virtual channels, 7 and 56, on the same license.