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

Spirit Airlines stock (SAVE) plunged 59% on Wednesday as the budget airline explores a deal with creditors to restructure its debt amid a reported threat of bankruptcy after merger talks with Frontier (ULCC) collapsed.

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%.