What happened

A federal judge in California has formally blocked the largest broadcast television merger in American history.

US District Court Chief Judge Troy Nunley issued a preliminary injunction on Friday preventing Nexstar Media Group and Tegna from operating as a combined entity. The ruling freezes a $6.2 billion deal that had already closed in March after rapid approval by the FCC and the Justice Department.

Why it matters: the combined company would own 265 television stations in 44 states, most of them local affiliates of ABC, CBS, Fox and NBC. That concentration of ownership affects what local news Americans see and how much they pay for television.

The ruling

Judge Nunley found that the coalition of eight state attorneys general and satellite provider DirecTV are “likely to succeed on the merits” of their antitrust claims. He wrote that the FCC’s clearance process was “unusual” and that its regulatory oversight “did not curb the manifest anticompetitive effects of this acquisition.”

The attorneys general, all Democrats, argue that the merger would give Nexstar the power to raise retransmission fees charged to cable and satellite providers. Those costs are typically passed on to consumers.

DirecTV has argued separately that the combined company could demand higher carriage fees during contract negotiations, knowing that dropping popular local stations would cost the satellite provider subscribers.

Nexstar’s response

Nexstar released a statement saying the transaction “closed more than four weeks ago following receipt of all required regulatory approvals.” The company said it will appeal to the Ninth Circuit Court of Appeals.

The merger had been approved unusually quickly by both the FCC and the DOJ under the Trump administration, drawing criticism from media consolidation watchdogs who said the regulatory review was insufficient.

What happens next

The injunction remains in place until the antitrust lawsuit is fully resolved at trial. Nexstar’s appeal to the Ninth Circuit could take months. In the interim, the two companies must operate separately despite having formally merged on paper.

If the merger is ultimately unwound, it would mark one of the largest failed media deals in American history and could reshape the landscape for local television ownership.