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

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%.

The Journal reported that Spirit is looking to bankruptcy after talks with Frontier about reviving a merger broke down.

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,

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