The past month accounts for the largest sales (via Twitter/myfoxtampabay).

The incident is believed to possibly involve all Targets nationwide. A third-party forensics team has been hired by Target to further investigate this development. The security breach is so large the secret service is looking into it it as well.

The breach is believed to have begun on or around Black Friday, the largest shopping day of the year. Customers that shopped between Nov. 27-Dec. 15 may have been hacked and are encouraged to call the Target hotline (866) 852-8680 for any questions. Hacking can also be reported to the police and Federal Trade Commission. 

The incident involved both credit and debit cards, as well as the names, expiration dates and security codes of cardholders. 

"Target's first priority is preserving the trust of our guests and we have moved swiftly to address this issue, so guests can shop with confidence. We regret any inconvenience this may cause," said CEO Gregg Steinhafel. 

Online shopping was not affected by the hack. 

The security breach has been fixed and it is now believed to be safe to shop in the store again. 

Reach Executive Producer Jillian Morabito here.