New York CNN Business  — 

Sinclair Broadcasting will pay the largest civil penalty involving a broadcaster in the Federal Communications Commission’s history.

The FCC said in a news release Wednesday that Sinclair agreed to pay $48 million, as well as “abide by a strict compliance plan in order to close three open investigations.”

Those investigations include Sinclair’s disclosure of information with regard to its ill-fated acquisition attempt of Tribune Media stations in 2018. That deal — valued at $3.9 billion — was scrutinized at the time by FCC commission chair Ajit Pai, and the agency formally referred the proposed acquisition to an administrative judge hearing. They also called into question whether some of Sinclair’s divestments in the deal were a “sham.”

Tribune Media eventually terminated its merger agreement with the conservative-leaning Sinclair, the largest owner of local television stations in the US. Had the acquisition gone through, Sinclair stations would cover a majority of the country.

On Wednesday, the FCC indicated the agreement “also closes investigations into whether the company has met its obligations to negotiate retransmission consent agreements in good faith and its failure to identify the sponsor of content it produced and supplied to both Sinclair and non-Sinclair television stations.”

In the news release, the FCC said that Sinclair admitted to violating the FCC’s sponsorship identification rules.

FCC Chairman Ajit Pai said Wednesday that Sinclair’s conduct during its attempt to merge with Tribune was “completely unacceptable.”

“Today’s penalty, along with the failure of the Sinclair/Tribune transaction, should serve as a cautionary tale to other licensees seeking Commission approval of a transaction in the future,” he said.

Pai also said he disagreed with those who called for revoking Sinclair’s licenses. He described those demands as politically motivated.

“While they don’t like what they perceive to be the broadcaster’s viewpoints, the First Amendment still applies around here,” he said.

Sinclair said in a statement Wednesday evening that it “is pleased with the resolution announced today by the FCC and to be moving forward.”

“Sinclair is committed to continue to interact constructively with all of its regulators to ensure full compliance with applicable laws, rules and regulations,” it said.

The FCC indicated the previous record civil penalty for a broadcaster was in 2007 — a $24 million penalty paid by Univision.

- CNN’s Hadas Gold and Charles Riley contributed to this report