EnronUS law firms Vinson & Elkins and Kirkland & Ellis have come out fighting this week after being formally added to a major shareholder class action relating to the collapse of Enron – the largest claim ever levelled against a law firm.

US firm Milberg Weiss Bershad Hynes & Lerach filed the amended class action on Monday (8 April) on behalf of the University of California Board of Regents, the lead plaintiffs in the case which has pooled 60 actions.

Claimants are seeking to recover the $25bn (£17.4bn) lost in the energy giant's collapse last year. The amended list of defendants in the suit also includes nine banks: Barclays Capital, Deutsche Bank, Merrill Lynch, JP Morgan Chase, Credit Suisse First Boston, Citigroup, Deutsche Bank, Bank of America and Lehman Brothers.