WASHINGTON — When Sinclair Broadcast Group announced its intent to buy Tribune Media in a blockbuster merger last May, the company predicted that regulators would quickly wave through the deal.

But 10 months later, Sinclair remains locked in a prolonged battle with Justice Department antitrust officials over how many stations it must sell to get their approval. It is latest cloud over Sinclair’s $3.9 billion deal, coinciding with an internal investigation underway at the Federal Communications Commission into the agency’s relationship with the company.

The biggest sticking point for Sinclair appears to be how many stations it would need to sell in order to get its deal approved.

In its new proposal, Sinclair asked that it be able to keep multiple stations in greater Greensboro, North Carolina, greater Harrisburg, Pennsylvania, and Indianapolis.

[Sinclair operates two stations in the Triad, Tribune Media one. Sinclair also operates two stations in the Research Triangle area, two in eastern North Carolina and another in Asheville.]

The company said it should be able to have two of the top four stations in the local markets after the FCC’s action last November to relaxed rules barring too much concentration among top stations. Sinclair’s filing of an amended plan last week could indicate that the company believes it is close to a resolution with the Justice Department and that it is confident enough to start the process moving again at the FCC.

Fighting internet giants

At issue is how much power Sinclair, the country’s largest broadcaster, will have over local media markets and national television audiences. Sinclair has argued that by combining forces with Tribune, it will be able to bolster local news coverage and be a stronger competitor to internet giants like Facebook and Google.

The Justice Department is concerned that the merger will harm competition in several cities. The agency is looking at whether the deal could also give Sinclair too much power over television advertising and over licensing deals with cable and satellite companies that retransmit their broadcasts.

John Newman, a professor at the University of Memphis and a former antitrust official at the Justice Department, said previous big radio mergers — similar in many ways to the Sinclair-Tribune deal — had been approved by the Justice Department without a lot of focus on how consumers were harmed.

The treatment of the Sinclair deal, he said, shows that “the DOJ is getting more aggressive and looking at consumer welfare, too.”

The Justice Department and Sinclair declined to comment.

Deal expected eventually

The two sides are expected to come to an agreement eventually, according to three people familiar with the negotiations who would speak only on the condition of anonymity because the discussions were private.

But the Justice Department’s demands for more divestitures has added another layer of complexity to a deal that, from the moment it was announced, faced broad opposition from Democratic lawmakers and consumer groups. Opponents have argued that the deal would curtail the number of unique voices in media, reduce coverage of local news and decrease competition.

The FCC is reviewing the merger separately from the Justice Department, focusing on whether the deal is in the public’s interest. The agency is widely expected to approve the deal.

Last week, in an attempt to move closer to a resolution, Sinclair submitted a proposal to sell stations in big markets including New York and Chicago, as well as some smaller stations. The proposal would put many of the stations in trusts, an arrangement that has raised some concern from consumer groups that the company will try to operate them through partners down the road, because it runs some stations that way now.

The Tribune stations in New York and Chicago would not go into a trust, but Sinclair said it had reached agreements to sell those stations to third parties that it would partner with later. Selling them will help Sinclair get near an important threshold: owning stations that reach no more than than 39 percent of U.S. households, the limit under FCC rules.

FCC roadblock

The FCC review could hit another roadblock. The agency’s inspector general is looking into whether the FCC chairman, Ajit Pai, improperly coordinated with Sinclair on regulatory decisions that enabled the merger. The inspector general’s office says its policy is to not comment on the existence or the nonexistence of an investigation.

In addition, Sinclair’s new plan has not satisfied the Justice Department, which still seeks more divestitures, according to one of the people familiar with the investigation.

The government’s demands are an unexpected setback for Sinclair, which predicted its proposal would be met by more sympathy from regulators in the Trump administration.

Sinclair’s initial confidence was partly buoyed by a string of regulatory victories last year at the FCC, including the relaxation of a television ownership limit last April that enabled its $3.9 billion merger with Tribune. Analysts had expected more corporate consolidation under President Donald Trump, but the Justice Department’s response to Sinclair’s proposed deal for Tribune instead underscores a surprising skepticism toward big corporate mergers, particularly those involving the media industry. In November, the Justice Department sued to block AT&T’s $85 billion bid for Time Warner because of concern that the union of telecom and media giants would have too much power over streaming video entertainment.

“Clearly, the DOJ has honed in on the dangers of concentrated transmission and concentrated media content markets that is harmful to competition and to consumers,” said Gene Kimmelman, president of the public interest group Public Knowledge and a former senior antitrust official at the Justice Department.

The list of divestitures Sinclair proposed in its amended plan could still change, Marci Ryvicker, a senior analyst with Wells Fargo, said.

“We do not believe that this is the final list of the station divestitures,” Ryvicker wrote in a research note last week.