Possible defendants

Andersen 30-45 Enron ex-officials Barclays Deutsche Bank CIBC JP Morgan Citigroup Merrill Lynch CSFB Lehman Brothers Bank of America Vinson & Elkins Kirkland & Ellis McKinsey

The class-action lawsuit, led by the University of California and prepared by law firm Milberg, Weiss, Bershad, Hynes & Lerach, is on behalf of dozens of investors who collectively lost billions of dollars in Enron shares last year.

The suit accuses Enron executives and advisors of a long list of offences, centring around the off-balance-sheet partnerships that were used to conceal the firm's finances from investors.

And while early versions of the lawsuit named only 29 former Enron executives and Andersen, the accounting firm that audited its books, media reports suggest that the list of defendants has been widened.

Nine investment banks, over a dozen more Enron ex-officials, two law firms and possibly consulting firm McKinsey could be added to the list when the suit is filed later on Monday.

Wall Street targeted

The addition of banks to the defendants' list dramatically widens the scope of the lawsuit.

The banks involved are Britain's Barclays, Canadian Imperial Bank of Commerce, Germany's Deutsche Bank and six US finance houses - JP Morgan, Citigroup, Bank of America, Merrill Lynch, CSFB and Lehman Brothers.

The lawsuit has hit upon these firms since they helped Enron construct offshore partnerships, and traded with it in the derivatives and energy markets.

Also implicated in the partnerships are law firms Vinson & Elkins and Kirkland & Ellis, and even McKinsey - although it is still unclear whether the consulting firm will be among the accused.

Money matters

Part of the reason for the inclusion of new defendants is that Andersen may prove unable to come anywhere near meeting the plaintiffs' demands for compensation.

When the lawsuit was first prepared last autumn, it seemed feasible to extract hundreds of millions of dollars in compensation from Andersen - the world's number-five accounting firm - and former top Enron officials.

But the scale of the class-action suit has ballooned to $25bn, and Andersen has more or less disintegrated in the meantime, with many of its constituent parts signing merger deals with the other four audit giants.