Federal prosecutors announced charges against four men in what is now considered the biggest bank breach ever, according to Bloomberg.

The attack, which targeted financial institutions, publishers, online stock brokers and software firms, included breaches at JPMorgan Chase & Co. (JPM) , Dow Jones & Co., E*Trade FinancialCorp., Scottrade Inc. and Fidelity Investments of Boston. 

From the Bloomberg story:

The new allegations against the four, all previously charged, broaden dramatically the scope of a wide-ranging criminal enterprise with hacking at its core…

The hackers stole data of more than 100 million customers around the world, prosecutors said. Almost all their schemes, including the market manipulation, “relied for their success on computer hacking and other cybercrimes,” according to the indictment.

The defendants include alleged ringleader Gery Shalon and two others, Joshua Aaron and Ziv Orenstein. A second indictment accuses Anthony Murgio of conspiracy to operate an unlicensed bitcoin business called Coin.mx. Murgio was previously arrested in Florida. Shalon and Orenstein were arrested in Israel in August.

The defendants ran their scheme from 2012 to mid-2015 and laundered their money through at least 75 shell companies, according to the indictment.

The JP Morgan hack occurred in June 2014 but was not discovered until several months later. At that time the bank said that it believed no more than 1 million customers' data had been involved in the breach.

However, in October 2014 a securities filing by the bank revealed that the number was actually much more and now is estimated to include 83 million households and 7 million small businesses. The hackers stole the login credentials for a JPMorgan employee and were able to hack the country's biggest bank through an unprotected server.