The budget carrier is in advanced discussions with bondholders over a filing that could occur within weeks.

Spirit Airlines Inc. is preparing to file for bankruptcy protection after merger talks with Frontier Group Holdings Inc. broke down, the Wall Street Journal reported.

Spirit Airlines is in constructive discussion with its creditors and continues to explore strategic alternatives to improve liquidity, the ultra-low-cost carrier said on Tuesday. The negotiations, with a supermajority of the noteholders,

Spirit Airlines is preparing to file for bankruptcy protection after merger talks with Frontier Airlines broke down, the Wall Street Journal reported, citing people familiar with the matter. Shares of the company were down 39% at $1.8 after the bell. The stock has fallen nearly 80% this year, while the S&P 500 passenger airlines index jumped 52%.

Spirit Airlines stock fell by about 36% in afterhours trading after the Wall Street Journal reported that the Florida-based budget airline is in advanced discussions with bondholders to hammer out a bankruptcy plan.

Spirit Airlines is on the brink of filing for Chapter 11 bankruptcy protection following the collapse of its merger talks with Frontier Airlines. With more than $3 billion in debt, Spirit is negotiating with bondholders for a restructuring plan that could allow it to continue operations under bankruptcy protection.

The ultra-low cost airline is gathering assets for a bankruptcy plan, which motions could be initiated in coming weeks.