A US law firm is asking a federal judge to approve nearly $700m (£342m) in attorney fees for its efforts to help Enron shareholders and investors recoup billions they lost after the once-mighty energy company collapsed, according to US press reports.

San Diego firm Coughlin Stoia Geller Rudman & Robbins said it had helped plaintiffs recover almost $7.3bn (£3.57bn) so far, mostly from financial institutions investors claim played roles in the accounting fraud that led to Enron’s 2001 unraveling. If approved, the attorney fees would be the largest ever in a securities fraud case.