A huge cyber attack against JPMorgan Chase this summer compromised customer information for about 76 million US households and seven million small businesses, the bank said.

Four Russian nationals and a Ukrainian have been charged in the US with running a sophisticated hacking organisation, stealing at least 160 million credit card numbers and causing losses of hundreds of millions of dollars.

A former US government informant was charged over the country’s largest case of credit and debit card data theft.