As reported by the New York Times, the investigation is focused on Pai’s decision to relax rules limiting the ownership of television stations by a single company. Pai reinstated a technologically obsolete rule known as the UHF discount, giving some television stations less weight in calculating whether a single owner exceeds a legal cap limiting its reach to 39% of the U.S. population.

That rule change effectively creates a loophole that would allow Sinclair’s planned $3.9 billion acquisition of Tribune Media, which would put Sinclair stations in 72% of U.S. households. That would represent a historic level of media consolidation, which has long been criticized as a threat to healthy democratic discourse. Despite the spread of online news, television is still the dominant source of news for Americans.

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One major backer of the investigation into Pai’s decision is Frank Pallone, a Democratic Congressman from New Jersey. Pallone told the Times that “for months I have been trying to get to the bottom of the allegations about Chairman Pai’s relationship with Sinclair Broadcasting.” Some of those allegations were unearthed in a Times investigation last August, which found that Pai had communicated closely with Sinclair executives as he rolled back rules, and that his decisions often aligned closely with Sinclair priorities.

A key issue in any investigation would be whether Pai’s decisions were specifically aimed at benefiting Sinclair. But last year’s Times report concluded that the alignment was based at least in part on shared ideology, with Pai reportedly believing that local television broadcasters, without the ability to consolidate, are at a competitive disadvantage to far-reaching cable networks and streaming services.