JP Morgan Chase will put its case to investors, one day after a dramatic fall in its share price that began when US politicians accused the banking giant of helping failed energy trader Enron to hide its debts.

Both JP Morgan and its co-accusee Citigroup saw their shares fall more than 15% on Tuesday, as their executives sat in a US Congressional committee listening to investigators outline their firms' alleged wrongdoing.

A conference call scheduled for 1300 GMT would allow it to discuss the decline in its share price, JP Morgan said, although it would not give further details of what it was prepared to talk about.

Investors will want to know whether there are any more skeletons in the closet, given investigators' assertions that the bank has made a number of similar deals with other companies.

Clean hands

Both banks deny they did anything wrong when they paid Enron billions in the form of "prepay" energy deals.

Senate hearings are set to continue

The money was channelled to the now-bankrupt energy firm through offshore companies, often in the UK's Channel Islands, and in theory amounted to advance payments for future energy trades.

But the investigators say that they were in reality little more than loans, designed in such a way as to avoid having to report them as such to investors.

Had they been correctly reported, the investigators believe, Enron's debts would have been 40% higher, hastening its descent into bankruptcy.

'Accounting sham'

The banks' troubles follow the collapse of the accountants Andersen, brought down by the accusation it had knowingly helped Enron to hide behind shady accounting practices.

Experts have now told investigators that Enron would not have been able to dupe investors without the assistance of its bankers.

"Chase and Citicorp knew what Enron was doing, assisted Enron in the deceptions, and profited from their actions," said Senator Carl Levin, chairman of the sub-committee on investigations, calling the action an "accounting sham".

And the report from the investigators made it clear that Enron was not the only beneficiary of the banks' assistance.

"Chase informed the subcommittee that it entered into Enron-style prepays with seven companies apart from Enron," the report said.

"Citigroup indicated that it shopped the idea to 14 companies apart from Enron, successfully selling it to at least three."