"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," Sears spokesman Howard Riefssaid in a statement on Friday.
"We have found no information based on our review of our systems to date indicating a breach," he added.
He did not say when the operator of Sears department stores and Kmart discount stores had begun the investigation or provide other information about the probe. Sears Holdings Corp operates nearly 2,500 retail stores in the United States and Canada.
Bloomberg News reported on Friday that the U.S. Secret Service was investigating a possible secret breach at Sears, citing a person familiar with the investigation. The report did not identify that source by name. The Bloomberg report said that its source did not disclose details about the scope or timing of the suspected breach.
A spokesman for the U.S. Secret Service declined comment when Reuters asked if the agency was investigating a possible breach at Sears.
The Secret Service is leading the U.S. government's investigation into last year's attack on Target, which the company has said led to the theft of some 40 million payment card numbers as well as another 70 million pieces of personal data.