Shares of Enron Corp. plunged to their lowest level in more than a decade on investor concerns more debt problems loom at the crippled energy trading giant.

In trade on the New York Stock Exchange, shares of Enron closed off $2.07, or 22.9 percent, at $6.99, after touching an intraday low of $6.55 -- a low not seen since May 1991. 

Enron was far and away the day's most-active stock, with more than 55.5 million shares changing hands. Volume was more than double the second most-active issue, Xerox Corp. 

"Everyone wants to sink the ship faster. This is a sell-off from yesterday's news which was hyped by the media," said Fulcrum Global Partners analyst Michael Barbis. 

Enron warned in a U.S. Securities and Exchange filing released after markets closed on Monday that it could be forced by next week to pay $690 million in debt because of a credit downgrade on Nov. 12. 

The filing made the stark statement that Enron would fail to be a "going concern" if a further credit cut forces it pay off $3.9 billion in debts to partnerships it is involved in. An early payoff of those debts would render Enron unable to service its revolving credit accounts, starting a downward spiral, it said. 

Meanwhile, credit rating agency Standard & Poor's said that it may again cut Enron's BBB-minus rating, which could trigger those debt payoffs. But the agency said Enron's liquidity issues were unlikely to derail its merger with smaller cross-town rival Dynegy Inc. 

Analysts said there were no surprising revelations in Enron's filing yesterday and that it should have no effect on plans by rival energy trader Dynegy Inc. to buy Enron. 

"The facts have not changed so dramatically for the stock to be down this magnitude," Barbis said. 

On Monday, Enron disclosed it is up against a Nov. 26 deadline, when it must deliver collateral against the debt owed to a third party in one of its myriad partnerships. 

If not, the partner has the right to liquidate all of the assets of the partnership, which include a Brazilian natural gas company that Enron was counting on selling to raise $250 million in cash. 

Enron is working to make alternative payment arrangements, since it can ill-afford to pay the debt now. Enron has already maxed out its $3 billion credit line, secured roughly $2 billion in loans and is looking for more cash to stay afloat. 

"Enron has access to more than $3 billion in cash. They can pay off this note. They have cash coming in and are not illiquid," said Barbis. "The timing of the note could have been better, but Enron keeps cash on hand for situations like this. This will not undermine the Dynegy deal." 

On Monday, the Houston-based company also reduced previously reported 2001 third-quarter earnings by 3 cents per share and increased reported earnings for the first 9 months of the year by a penny per share.