Sears said Friday it has launched an investigation to determine whether it was the victim of a security breach, following Target Corp's revelation at the end of last year that it had suffered an unprecedented cyber attack.

The U.S. Secret Service is investigating a possible security breach at Sears Holdings Corp., after a series of cyber attacks on retailers that have exposed the credit-card data of millions of U.S. consumers, a person familiar with the investigation told Bloomberg News.

The person, who asked not to be named because the matter is under investigation, didn’t disclose details about the scope or timing of the possible breach.

Hoffman Estates-based Sears said it has found no evidence that it has been hacked.

"There have been rumors and reports throughout the retail industry of security incidents at various retailers, and we are actively reviewing our systems to determine if we have been a victim of a breach," the company said in a statement. "We have found no information based on our review of our systems to date indicating a breach."

The U.S. Secret Service is already investigating digital attacks on several other retailers, including Target Corp. and Neiman Marcus Group, that have exposed the credit-card data of millions of U.S. consumers.

Sears said on Thursday it lost $1.36 billion last year, but noted its loss narrowed in the last three months of the year. The retailer has consistently lost money for more than two years.

- Bloomberg News contributed to this report.