A hacker by the Twitter name Reckz0r managed to break through into networks of dozens of banks and stole customers' information.
(http://asset0.cbsistatic.com/cnwk.1d/i/tim/2012/06/18/Screen_shot_2012-06-18_at_4.07.35_PM_610x283.jpg)
Reckz0r Tweets his accomplishment after three months.
Reckz0r who posted part of the proof of his claims on Twitter, just a week ago had announced his retirement from hacking to being a whitehat (http://en.wikipedia.org/wiki/White_hat_%28computer_security%29). However he did not retrieve all the VISA and Mastercard information but only hacked the banks, #chase etc.
According to CNET, there was a link to a site with downloadable data having around 1700 accounts in the U.S and other cities of the world. Other reports also stated that the data was 50 gigabytes and 113 pages.
Reckz0 maintained though that he had his last activity on the hacking scene and apologysed to those exposed.
Sources: cnet