Greets and saluts from the NYC metro area. The big news of the day is that anyone who may have shopped at Target from November 27 through December 15 may have had their credit/debit card information stolen in one of the biggest hacking cases to date.

Up to 40 million accounts may be jeopardized by this, and the company wants people to check their bank/credit accounts for unauthorized charges and to contact the company if they find problems.

Target said that it had alerted authorities and banks, and that the issue was “identified and resolved.” Still, it encouraged customers to look over their account statements and obtain credit reports. Target did not say how it might have happened.

“It is very clear it is a sophisticated crime,” Molly Snyder, a spokeswoman for the company, told Reuters.

At up to 40 million customers, the breach ranks among the biggest in U.S. corporate history. In 2007, the data of more than 45 million customers was stolen from stores including T.J. Maxx and Marshalls.

Last year, the Barnes & Noble bookstore chain said that someone had planted software in PIN pad devices at 63 of its stores in nine states to steal the data from magnetic card stripes. The company responded by taking PIN pad devices out of all its stores.

And in 2011, a hack exposed the credit card information of 100 million user accounts on the Sony PlayStation video game network.

Target, with almost $72 billion in U.S. sales last year, is the third-largest store in America, trailing only Walmart and the Kroger grocery store chain. Target has about 1,800 stores in the United States.

Krebs on Security reported that the breach hit only customers who shopped at physical Target stores, not online. The blog cited reliable sources familiar with the matter.

The data would allow criminals to create counterfeit cards by encoding the information onto any card with a magnetic stripe. If PIN codes were also intercepted, that would allow criminals to withdraw the cash of unsuspecting customers from ATMs.