The man accused of stealing proprietary computer code from Societe General was refused bail last week because the court feared he was a flight risk.
Samarth Agrawal was a trader at Societe General. He was caught allegedly copying code which ran the bank's high-frequency trading systems.
26-year-old Agrawal was arrested on Monday. FBI officials found code printouts at his apartment, Reuters reports.
He has been charged with theft of trade secrets and could face up to five years in prison if convicted.
Agrawal was due to start work at another firm on Monday but was arrested before he could start. ®