(CN) - As New York's attorney general announced a nationwide investigation, Target disclosed Friday that last month's data breach may have affected as many as 110 million shoppers, a big revision to its original estimate of 40 million.
Dozens of federal class actions have been filed against the retailer since the company's Dec. 19 announcement that a security breach implicated as many as 40 million credit and debit cards swiped between Nov. 27 and Dec. 15,
Target said Friday the scope of the breach was much broader than initially thought.
The initial estimate of 40 million accounted for shoppers whose payment card data was disclosed, but Target said Friday that, upon further investigation, the breach affected an additional store of data on 70 million shoppers.
This implicated store includes names, mailing addresses, phone numbers and email address of shoppers, Target said.
With the breach now expected to have affected 110 million shoppers, Target has allowed that there could be overlap between the two groups of customers.
The New York Times meanwhile reported that "the latest subset of potential victims includes customers who may not have shopped at Target during the holiday period."
Target has pledged not to hold shoppers responsible for any fraudulent charges incurred by the breach, and it will offer one year of free credit monitoring and identity-theft protection to all in-store shoppers.
"I know that it is frustrating for our guests to learn that this information was taken and we are truly sorry they are having to endure this," Target President and CEO Gregg Steinhafel said in a statement.
New York Attorney General Eric Schneiderman announced Friday that he is participating in a national investigation into the breach.
He called the revelation "troubling" and said shoppers "deserve companies that protect their personal information when they shop on their websites and in their stores."
Target plans to contact those for whom it has email addresses with tips on guarding against consumer scams.
The retailer has 1,921 stores in the United States and Canada.
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