A group of investors has pulled out of a plan to inject $2.6bn in equity into Delphi, throwing the restructuring of the bankrupt US automotive parts maker into doubt.

In a letter to Delphi on Friday, the investors, led by Appaloosa Management, a New Jersey-based hedge fund, said that they were giving notice of “immediate termination” of the agreement, citing a series of alleged breaches that risked costing the group hundreds of millions of dollars.