A federal judge moved to block the proposed merger between Nexstar Media Group and Tegna on Thursday, issuing a preliminary injunction that puts the deal on hold until an antitrust trial can be completed. The ruling represents a significant setback for the two broadcast television giants, who had sought to combine their station portfolios in a deal that would have created a dominant force in local television broadcasting across the United States.

The Justice Department had filed suit to stop the merger, arguing that combining Nexstar and Tegna would substantially reduce competition in local television markets, potentially harming consumers and advertisers alike. The judge's decision to grant the injunction signals that the government's antitrust concerns carry enough legal weight to warrant a full trial before the deal is permitted to move forward.

Nexstar is already the largest local television station owner in the country, and Tegna operates dozens of stations in major markets. A combined entity would control a vast share of local broadcast reach nationwide, raising concerns among regulators about the concentration of media ownership and its implications for local news coverage and advertising competition.

The preliminary injunction does not resolve the underlying antitrust case, but it prevents the companies from closing the transaction while litigation proceeds. Both Nexstar and Tegna have not yet indicated publicly whether they intend to continue pursuing the deal through trial or explore other options, including potentially renegotiating or abandoning the merger agreement.