Societe Generale's report of fraud comes four months after French competitor Credit Agricole SA said an unauthorized proprietary trade at its investment-banking unit in New York cost it 250 million euros.

Societe Generale said that it's already closed all the positions set up by the trader, who had used his experience working in the back office to hide his trades through fictitious transactions. The fraud was discovered Jan. 19 and 20.

Societe Generale said it's taking 1.1 billion euros of writedowns linked to the U.S. residential real estate market, 550 million euros linked to U.S. bond insurers, and 400 million euros on other unspecified risks.

In the third quarter, the bank reported 375 million euros of writedowns and trading losses linked to turmoil in financial markets. The world's biggest financial companies have announced more than $120 billion in writedowns and credit losses as the U.S. housing slump rattles debt markets.

Societe Generale's exposure to bonds backed by home loans is now down to 35 million euros, the bank said.

To contact the reporter on this story: Gregory Viscusi in Paris on