The U.S. Secret Service is investigating a possible security breach at Sears Holdings Corp. after a series of cyberattacks on retailers, according to a person familiar with the investigation.

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.

“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,” said Howard Riefs, a Sears spokesman. “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 shares declined more than 2 percent after Bloomberg News reported on the breach. The stock traded at $43.88, up 2 percent, as of 2:42 p.m. in New York.

Sears is attempting to mount a comeback under Chief Executive Officer Edward Lampert, the hedge-fund manager who took the reins of the company a year ago.

He’s investing in e- commerce and rewards programs in a bid to reverse a 28-quarter sales decline. He also has sold assets and sought to shrink the company’s store base, saying retailers  need less square footage.