UK fines US bank Citigroup over European 'flash crash'

British financial regulators Wednesday fined US bank Citigroup for failures in its trading controls after a "flash crash" incident in 2022 that saw huge selling of shares in Europe.

The Financial Conduct Authority (FCA) and Prudential Regulation Authority (PRA) imposed combined penalties of £61.6 million ($78.3 million) for failures by the bank's London division, Citigroup Global Markets Limited.

Citigroup has since taken actions to strengthen its controls, the regulators said in statements.

"Failures in the firm's systems and controls led to $1.4 billion of equities being sold in European markets when they should not have been," the FCA said of the "fat finger" trade.

PRA noted that "an experienced trader incorrectly inputted an order".