An internal investigation at French bank Société Générale has found that rogue trader Jérôme Kerviel allegedly used three techniques across more than 1,000 transactions to carry out and conceal his positions before the record €4.9bn ($7.7bn) trading fraud was discovered in January.

The revelations were published today by SG as it released a trio of reports connected to the fraud, one by its general inspection department on its investigation into the fraud, one by a three-man special committee formed by the bank in the aftermath of the fraud’s discovery, and one by PwC’s audit team, which was hired to diagnose weaknesses in SG’s controls and to analyse the bank’s subsequent action plans.