Citi fined $78 million after a European trader's fat-finger trade caused a flash crash in stocks

TOKYO, JAPAN - JANUARY 15, 2014: Shoppers walk past the entrance to a Citibank branch facility in Tokyo's trendy Shibuya district. (Photo by Robert Alexander/Getty Images)

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• A trading mistake at Citigroup in 2022 has led to a $78 million fine against the bank.
• The "fat-finger" trade caused a brief flash crash in European stocks in May 2022.
• The brief flash crash caused by the mistaken trade briefly wiped out $322 billion in market value.