US insurance firms are likely to be liable for losses of at least £2.5 billion sterling due to the collapse of Enron.
But credit rating agency Standard & Poor's said the losses of around $3.5 billion are unlikely to affect the financial health or financial ratings of these insurers.
Standard & Poor's says the majority of losses will be investments made in Enron bonds or other securities by insurance portfolio managers.
But it notes many insurers sold some or all of their holdings in the weeks preceding the group's filing for bankruptcy protection.
Amalgamated Bank said it has filed a legal action seeking to freeze the bank account of Enron executives and alleges they were involved in insider trading by misrepresenting the energy firm's finances.
Amalgamated Bank claims insider trading enabled Enron management to siphon off profits of more than £777 million in securities sales.
The bank's suit, filed in Houston, claims 29 of the company's top executives sold more than 17.3 million shares worth $1.1 billion over three years.
Enron faces a growing list of lawsuits following its collapse, which began last month when it emerged it was obscuring huge financial losses incurred in partnerships run by the management.
PA