NEW YORK (CNNMoney.com) - Former Enron Chairman and CEO Ken Lay has seen his personal fortune eaten away by the collapse of the energy trader and his legal problems, and he could be forced to file for bankruptcy protection, according to a published report.

The New York Times reported that Lay's stated net worth is now less than $650,000, down from as much as $400 million before Enron's downfall in 2001.

And the Times said that latest valuation is probably on the optimistic side. It includes an estimated $1.9 million held in a trust that the paper reports is almost sure to be consumed by legal fees.

Outside of that trust, his current holdings include an estimated $4.2 million in real estate and $220,000 in other liquid assets. His retirement benefits, once worth $68 million, have fallen to $3.5 million, according to the report.

The paper reports he has spent $20 million of Enron insurance proceeds for his defense, along with $5 million of his own money. He also has $4 million in unpaid legal fees and could see his total legal costs reach $30 million, according to the paper.

The Times reports his financial outlook is more dire than those of Jeff Skilling, who also served as CEO of Enron, but who left the company months before its problems became public.

The Times does not give any estimates of Skilling's worth, but the paper said his Enron stock was not encumbered by loans as Lay's was, and he cashed out a big chunk of his shares before Enron's troubles were exposed.

The two men are co-defendants in a criminal trial now taking place in Houston. They face more than three dozen fraud and conspiracy charges, which accuse them of lying to investors about the company's finances while profiting from the sale of millions of dollars in stock. But Michael Ramsey, one of Lay's attorneys, has argued his client never sold a single Enron share that he wasn't compelled to sell.

The Times reports that Lay, 63, could be forced to forfeit his remaining home, along with some other assets, if he is convicted in the criminal fraud trial. And he also faces potential liability from lawsuits that were filed against him by shareholders and others after Enron's collapse

Lay still lives in a full-floor apartment in the Houston's affluent River Oaks neighborhood. But he cannot sell that dwelling because it is subject to forfeiture in the criminal case, according to the report.

For a look at the most recent testimony in Lay and Skilling's criminal case, click here.

For a look at a special report, Enron on Trial, click here.