Target revealed last week that data connected to about 40 million credit and debit card accounts were stolen between Nov. 27 and Dec. 15. The company said on Friday that there's no indication that information like a customer's date of birth or Social Security number were taken.
Target has been trying to deal with fallout from the breach during what is typically the busiest shopping season of the year. By Monday evening, more than a dozen Target customers had filed federal lawsuits around the country, with some accusing Target of negligence in failing to protect customer data.
Target issued an apology to customers and offered a 10-percent discount to customers who shopped on Saturday and Sunday, and free credit-monitoring services to those affected by the breach.
Some shoppers may be scared off by the data breach. Overall, Customer Growth Partners LLC, a retail consultancy, estimates that the number of transactions at Target fell 3 percent to 4 percent on Saturday, compared with a year ago. The Saturday before Christmas is usually one of the top busiest days of the season.
Attorney Robert Ahdoot, representing one shopper, filed a lawsuit in San Francisco in hope of being certified as part of a class action. Ahdoot said his law firm, Ahdoot and Wolfson in Los Angeles, has been contacted constantly from people who allege to be Target customers.
"Since we filed, every day through the weekend, we are getting calls from individuals around the country ? either they've had unauthorized withdrawals from their debit cards or they had unauthorized uses of their credit card. Most say they've never had this problem before ever," he said.
He said he has fielded calls from California, Hawaii, Florida, Texas, Arizona, New Jersey and New York, to name just some of the states. Kirk's lawsuit accuses Target of negligence, invasion of privacy, and other actions. A spokeswoman for Target declined to comment about the lawsuits.
On Saturday, JPMorgan Chase and Co. said it is notifying customers who used Chase debit cards at Target in the security breach time period are limited to $100 a day of cash withdrawals and $300 a day of purchases with their cards, affecting about 2 million accounts, or 10 percent of Chase debit cards. Shares of Target Corp., based in Minneapolis, fell 1.5 percent to $61.57 on Monday morning.
Target says the company is investigating, but it has not disclosed exactly how the breach occurred. Customers who see suspicious charges on their statements were advised to report them to their credit card companies and call Target at (866) 852-8680.
Target is based in Minneapolis and has nearly 1,800 stores in the U.S. and 124 in Canada.
ABC News and the Associated Press contributed to this report.