NEW YORK (TheStreet) -- Shares of Target (TGT - Get Report) were dropping Wednesday after U.S. Attorney General Eric Holder confirmed that the Department of Justice was looking into last month's security breach at the big box retailer.
Target shares were down 1.2% to $57.18. The stock hit a new 52-week low of $57.16 on Wednesday.
Holder testified on Wednesday at a U.S. Senate hearing.
"The Department of Justice takes seriously reports of any data breach, particularly those involving personally identifiable or financial information, and looks into allegations that are brought to its attention," Holder said in prepared remarks.
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"While we generally do not discuss specific matters under investigation, I can confirm the Department is investigating the breach involving the U.S. retailer, Target. And we are committed to working to find not only the perpetrators of these sorts of data breaches - but also any individuals and groups who exploit that data via credit card fraud," he said.
The Minneapolis-based company has already said that it was working with federal agencies including the Secret Service in response to the data breach.
Target disclosed earlier in January that not only had hackers been able to lift credit and debit card information from more than 40 million customers, but they were able to obtain names, mailing addresses, phone numbers and email addresses of up to 70 million customers. It was not clear how much overlap there was of the separate breaches.
Target has repeatedly said that guests will have zero liability for the cost of any fraudulent charges. The company is offering free credit monitoring and identity theft protection for customers for up to one year.
Target said two weeks ago that it was investing $5 million in a multi-year campaign to educate consumers about cybersecurity and the dangers of phishing scams.
Separately, the company said on Wednesday that it plans to continue its expansion in Canada, adding another nine stores, bringing its total there to 133. Target has 1,797 stores in the U.S.
--Written by Laurie Kulikowski in New York.