The exact size of the breach is unknown, but may involve more than 10 million compromised cards, Krebsonsecurity reports. The data stolen may include full Track 1 and Track 2 information, which would make it easy for criminals to create counterfeit cards using the stolen data. The company halted trading Friday afternoon, sending shares of the company down nine percent. The breach occurred between late January and late February, 2012, according to the Wall Street Journal. Visa and MasterCard now have confirmed that they are investigating the breach.
Source: https://threatpost.com/report-visa-mastercard-warn-breach-card-processor-033012/76383/