2009 Records: World's Biggest Data Breach

"Talk about a credit crisis: Heartland Payment Systems, a credit card payment processing firm, may have been the victim of the largest data breach to date. The Princeton, N.J.-based firm said Tuesday that it discovered malicious software in its systems that compromised the security of the data traversing its network. It's unclear what data may have been tampered with or stolen..."

http://information-security-resources.com/2009/01/21/isr-news-worlds-biggest-data-breach/