JetBlue Airways said Friday it may pull out of a $3.8 billion acquisition of Spirit Airlines after a federal judge blocked the deal.

The announcement comes just a week after JetBlue and Spirit said they would appeal the decision, which was made in an antitrust case brought by the Justice Department.

in a regulatory document On Friday, JetBlue said the deal could be terminated after Sunday if certain conditions were not met. Spirit said in his own presentation that he disagreed with JetBlue’s argument and believed there was “no basis to terminate” the agreement.

A federal judge in Boston blocked the proposed merger on Jan. 16, ruling that Spirit plays an important role in keeping airfares low and that an acquisition by JetBlue would hurt travelers. The ruling was a victory for the Justice Department, which under Biden has sought to limit corporate consolidation across the economy.

The companies said last week they were preparing an appeal. As part of the merger deal, JetBlue agreed to pay Spirit and its shareholders a combined $470 million if regulators blocked the deal.

Spirit’s stock price fell about 16 percent Friday morning. Its shares have lost more than half their value since the deal was blocked because the company is unprofitable and investors fear the airline is taking on too much debt. Spirit was also forced to ground some of its planes due to an engine problem.

The stock price of JetBlue, which could save billions of dollars by not filing an appeal and moving forward with the deal, rose a bit Friday morning.