Trader Combined Methods of Fraud, French Bank Says

PARIS — Société Générale said yesterday that a trader who evaded all its controls to bet $73.5 billion — more than the French bank's market worth — on European markets hacked computers and "combined several fraudulent methods" to cover his tracks, causing billions in losses.

The bank says the trader, Jerome Kerviel, did not appear to have profited personally from the transactions and seemingly worked alone — a version reiterated yesterday by the chief executive of the bank's corporate and investment banking arm, Jean-Pierre Mustier.

But, in a conference call with reporters, Mr. Mustier added: "I cannot guarantee to you 100% that there was no complicity."

Mr. Kerviel's lawyer said the accusations of wrongdoing against his client were being used to hide bad investments by the bank related to subprime mortgages in America.