Target Breach Affected Up to 110 Million Customers Target on Friday raised its estimate of the number of customers whose credit and debit card data were stolen late in 2013. Target on Friday extensively revised the estimated number of customers exposed by the widescale hack of its data during the holiday season, disclosing that 70 million to 110 million people had their personal information stolen. Target, which originally said on Dec. 19 that about 40 million in-store customers had data stolen between Nov. 27 and mid-December, also revealed that additional types of information - mailing and email addresses, names and phone numbers - were hacked. Before Friday, Target had disclosed that hackers stole customer names, credit or debit card numbers, expiration dates and security codes for only those customers who had shopped in its stores. This additional trove of data involves all kinds of customer information that Target had collected over time. Those customers need not have even shopped at Target during the holiday period to have had their information stolen. Target coupled the release of a more damaging breach with news that the disclosures had severely dampened its holiday sales in the final weeks. "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," Gregg Steinhafel, the Target chief executive, said in a statement. I also want our guests to know that understanding and sharing the facts related to this incident is important to me and the entire Target team. A company spokeswoman said that there may be overlap between the 40 million people whose payment information was breached in Target's stores and the 70 million whose information was stolen regardless of whether they shopped. The spokeswoman, Molly Snyder, said the two batches of data were stolen as parts of the same overall theft. Fraud experts said the information stolen from Target's systems quickly flooded the black market. On Dec. 11, shortly after hackers first breached Target, Easy Solutions, a company that tracks fraud, noticed a ten- to twentyfold increase in the number of high-value stolen cards on black market websites, from nearly every bank and credit union. The data breach, confirmed less than a week before Christmas, could not have come at a worse time for Target. The holiday season can account for between 20 percent and 40 percent of a retailer's annual sales, according to industry groups. Target tried to entice wary customers to shop by offering a 10 percent discount on purchases in its stores the weekend before Christmas. But it appears that offer did not attract significant interest. Target said it began the fourth quarter with "stronger than expected" sales. Following the breach announcement in December, sales became "meaningfully weaker than expected." The company said it now expected a comparable sales decline of 2 percent to 6 percent for the remainder of the quarter. Overall, Target indicated that comparable sales were likely to fall 2.5 percent in the fourth quarter over the same period a year earlier. Previously, the company had estimated that sales would be flat. "In light of the recent data breach, our top priority is taking care of our guests and helping them feel confident in shopping at Target," John Mulligan, the chief financial officer, said in a statement. At the same time, we remain keenly focused on driving profitable top-line growth and investing our resources to deliver superior financial results over time. The retailer also announced on Friday that it would close eight underperforming United States stores in May, in locations including Las Vegas, Memphis and Middletown, Ohio.