Talk swirled late Wednesday that Target Corp. is allegedly investigating a data breach that may involve millions of customer credit and debit card records.

This story first appeared in the December 19, 2013 issue of WWD. Subscribe Today.

The breach reportedly extends to nearly all Target locations in the U.S., and involves the theft of data stored on the magnetic stripe of cards. It involves cards used in stores and not online. The breach is said to have begun on Black Friday.

Initially, it was thought to have occurred from after Thanksgiving to Dec. 6, but over the past few days, investigators have reportedly found evidence extending the breach by at least a week, to Dec. 15. Target did not respond to a request for comment.

One of the largest retail breaches occurred in 2007 when 45.6 million credit and debit card numbers were stolen from The TJX Cos. Inc.’s systems.