The Enron Corporation, the nation's leading wholesale electricity marketer and natural gas trader, posted a third-quarter loss yesterday because of more than $1 billion in one-time charges for various businesses.

The company reported a net loss of $618 million, or 84 cents a share, in contrast to net income of $292 million, or 34 cents a share, in the period a year earlier. Excluding charges, Enron said it earned $393 million, or 43 cents a share. Revenue jumped 59 percent, to $47.6 billion, from $30 billion a year ago.

The charges, which total $1.01 billion, or $1.11 a share, included a $287 million write-down on Azurix, the company's troubled water-management division, and $180 billion in restructuring charges at its broadband telecommunications operation.

But more than half the charges were related to various investment losses, mostly from Enron's stake in the New Power Company, a retail electricity joint venture with AOL Time Warner and I.B.M.