A single trader, Nick Leeson, hid £827 million in losses and destroyed Barings — Britain’s oldest merchant bank, founded in 1762. After the 1995 collapse, the 233-year-old institution was sold to ING for one pound.

In 2008 a single Société Générale trader, Jérôme Kerviel, ran up €4.9 billion in losses on unauthorized positions — the largest rogue-trader loss on record at the time. A court later slashed the damages he personally owed, faulting the bank’s own risk controls.