Visa (V -0.5%) and MasterCard (MA -0.5%) reportedly sent alerts to banks late last week of a...

|About: Visa Inc. (V)|By:, SA News Editor

Visa (V -0.5%) and MasterCard (MA -0.5%) reportedly sent alerts to banks late last week of a "massive" security breach at one of their U.S.-based credit card processors, and certain cards may have been compromised. The breach is believed to have occurred between Jan. 21 and Feb. 25, and could involve as many as 10M credit card numbers.