A French 'rogue trader' who allegedly defrauded the bank Societe Generale of 4.9bn euros ($7.2bn) has been taken into police custody in Paris, judicial sources have said.
Jerome Kerviel, 31, was taken to the headquarters of the Paris police's financial brigade at about 2pm (1300 GMT), the source said.
Societe Generale announced its colossal losses on Thursday, which reduced the bank's 2007 profits to 600-800 million euros from 5.2bn euros in 2006.
The detention followed a police raid on Kerviel's apartment on Friday in Neuilly sur Seine, a Paris suburb, where documents were seized.
Enquiry demanded
Kerviel, who had been at the bank since 2000, allegedly used intricate methods to trade without the bank's authorisation on the world future markets.
The scale of the losses was eventually uncovered by back-office staff during a routine check.
The French government has demanded a full accounting of the scandal over the fraud.
Societe Generale's losses dwarf those sustained by Barings, a British bank, in 1995.
Nick Leeson gambled away $1.5bn at Barings, causing it to collapse.