As Trafigura Group’s metal traders were partying in London at last year’s LME Week jamboree, Citigroup Inc. was taking a step that would end up shaking their world.
Until late October, the US bank had been helping to finance Trafigura’s nickel trades with companies linked to Indian businessman Prateek Gupta — deals which Trafigura now says were part of a “systematic fraud” against it that could cost more than half a billion dollars.