Securities & Exchange Commission accused Fabrice Tourre of misleading investors about sub-prime mortgage securities that he knew were doomed to fail. That allowed a Goldman Sachs client, Paulson & Co, to secretly bet against the investment.
The regulator alleged that he failed to declare that Paulson had helped choose, and intended to bet against, mortgage securities underlying the 2007 deal.
According to the Guardian: "Some of the testimony centred on personal emails sent by Tourre, who grew up in France and moved to the US in 2000 to study at Sanford, to his girlfriend back in Europe. In the email, sent as the markets teetered on the edge of panic, Tourre referred to himself using the nickname "Fabulous Fab". The moniker leant itself to the idea of corporate greed and vanity running riot at a time when investors were losing savings."
