Jérôme Kerviel is one of the biggest “rogue traders” in history. Like many other rogue traders, Kerviel could have been the weakest link that brought down an entire bank. However, his actions were only possible due to a lax enforcement of controls.

Over the course of a brief stint at Société Générale, Kerviel covered up his speculative bets with falsified trades and emails. His speculation came to a head in 2008 when a falling market caused 4.9 bn € in losses.

Kerviel maintains that direct managers at Delta One actively encouraged him to engage in these trades. Regardless how culpable other individuals may have been, the Kerviel affair lays bare what can go wrong when basic standards are not in place or not enforced.