5. JPMorgan Chase & Co and the "London Whale"
In 2012, one of JPMorgan Chase & Co’s employees, Bruno Iksil, nicknamed the "London Whale," managed to lose at least $6.2 billion for the company. Iksil had accumulated a massive amount of Credit Default Swaps (CDS) on the market as part of the bank’s hedge fund strategy. Soon, insiders began noticing that the market was affected by his aggressive trading style, and chaos ensued. It was eventually revealed that the risk model that was used involved manual copying and pasting of data from several different spreadsheets. The formulas had not been adjusted correctly, leading JPMorgan to be fined $920 million, and their CEO’s salary was cut in half in 2012, from $23 million to $11.5 million dollars.