Investment bank Citigroup has been fined £61.6million by City regulators after one of its traders accidentally hit sell on $444billion (£348.9million) of shares instead of £45.6million.

The Financial Conduct Authority said that an experienced trader at Citi made an inputting error when making trades that “coincided with a material short-term drop” in some European markets. In the City, erroneous or accidental sales like this are referred to as “fat finger” trades.

Although Citi’s…