Target disclosed on Friday that a mass information breach involved data belonging to up to 110 million individuals—a number far more extensive than originally believed.
The big box retailer said that a probe into the hacking of customers' personal data found that stolen information—separate from payment information already reported—included names, mailing addresses, phone numbers or email addresses for tens of millions. The new figure was significantly higher than the 40 million the company initially reported.
Although Target previously stated the breach wouldn't compromise card holders' accounts, the dramatic rise in the number of people affected called that assumption into question.
(Read more: Customers paying the price after data breach)
Dow Jones reported Friday that Target shoppers' information was stored separately from the 40 million credit and debit card accounts that the discount chain had said were affected back in December, when the breach was initially reported. Friday's disclosure indicated that a different system had been hacked.
(Target CEO Gregg Steinhafel will appear exclusively on CNBC Monday, January 13 in a "Squawk Box" interview, his first since the breach).