In Washington, it said the move followed renewed White House calls for late-night host Jimmy Kimmel to be fired.
The group said FCC chair Brendan Carr was using licence renewals to punish political enemies and chill newsrooms, while Democratic commissioner Anna Gomez called it the agency's worst First Amendment violation yet.
Open Markets said the order fits a broader pattern of alleged Trump-era pressure on media companies, linking it to earlier disputes over Kimmel, mergers and broadcast regulation.
How might this unprecedented FCC action permanently alter the relationship between the government and all US media companies?
What precedent is set when a TV host's joke is followed by a federal review of their company's licenses?
Could a company's diversity programs become the new justification for federal regulators to challenge its business licenses?