Christian Charriere-Bournazel, her colleague, said Kerviel had "handed over an expired passport", which means he could not leave the country.
 
Renaud van Ryumbecke and Francoise Desset, the investigating judges, rejected the bid by Jean-Claude Marin, the prosecutor, to charge Kerviel with the more serious crime of "attempted fraud".
 
Kerviel is also formally prevented from communicating with Societe Generale employees or working in any financial-services capacity, pending the outcome of the case.
 
'No takeover bid'

Police finished nearly 48 hours of questioning Kerviel on Monday.

Marin said Kerviel could face a maximum of seven years imprisonment if convicted under the charges.

Also on Monday, SocGen slightly revised the amount Kerviel allegedly lost the bank - from 4.9bn euros to 4.82bn.

Kerviel is alleged to have defrauded Societe
Generale of nearly 5bn euros [AFP]

Daniel Bouton, chief executive officer, said SocGen has not been approached by any suitor for a takeover.

However, shares in SocGen were trading down 6.6 per cent at 68.98 euros at noon on Monday, amid generally falling shares.

Bouton rejected suggestions from Kerviel's lawyers that SocGen was using Kerviel to hide big losses linked to the US subprime mortgage crisis.

"How could you want to imagine that we would have been able to hide a hole by another hole? It's completely stupid," Bouton told Europe-1 radio.

Huge gamble

Elisabeth Meyer, one of Kerviel's defence lawyers, said Kerviel's transactions were in the black up to December 31.

"In my view, he was thrown to the lions before being able to explain himself," said Meyer.

SocGen alleges that Kerviel hacked computers and "combined several fraudulent methods" to build up positions on futures markets worth 50bn euros.

The positions allegedly held by Kerviel were far more than SocGen's market worth.

SocGen said Kerviel's positions were cancelled last week over three days in a "controlled fashion".