American Express has begun notifying cardholders that their data may have been compromised in a third-party breach. Account numbers, user names and other information including expiration dates may be accessed. Credit card breaches have fallen off the radar since a brutal 12-month stretch starting in December 2013 during which Target, Home Depot, Michaels and other large retailers and payment processors suffered large breaches. American Express did not say how many records were accessed, nor did it identify the third party, or how the partner was compromised.
Source: https://threatpost.com/american-express-notifies-cardholders-of-third-party-breach/116817/