The U.S. Department of Justice is expected to sue to block the proposed merger of JetBlue Airways and Spirit Airlines, Politico reported late Friday.

The move was not unexpected given the Biden administration’s public position against large mergers in already consolidated industries. Four airlines — American, Delta, Southwest, and United — control nearly 80 percent of the U.S. market.

JetBlue has argued that its deal to buy Spirit for $3.8 billion would create a stronger competitor to its big four competitors. The combined carriers would have roughly a 9 percent share of U.S. domestic traffic, and be the fifth largest in the country. On Thursday, JetBlue outlined at least eight new routes the combined airlines could potentially add.

“This isn’t Pepsi and Coke merging,” JetBlue President and Chief Operating Officer Joanna Geraghty told Reuters on Wednesday.

The DOJ’s suit, which Politico reported could come as soon as March, is not necessarily the end of the deal. The regulator similarly moved to block the merger of American and US Airways in 2013 before reaching an out-of-court settlement that allowed the merger to go forward several months later.

Spirit shareholders approved the deal in October, after JetBlue beat Frontier Airlines in a bidding war for Spirit last July.

Tags: airlines, jetblue airways, spirit airlines, spirit takeover