March 17 Beauty products retailer and distributor Sally Beauty Holdings Inc said "fewer than 25,000" credit-card records may have been taken in a recent data breach.
The company said on March 5 it discovered that its network had been hacked but added no card or customer data appeared to have been stolen.
Sally Beauty said on Monday that an investigation by forensics firm Verizon had discovered the evidence that card payment data may have been removed.
"As experience has shown in prior data security incidents at other companies, it is difficult to ascertain with certainty the scope of a data security breach/incident prior to the completion of a comprehensive forensic investigation," Sally Beauty said.
"As a result, we will not speculate as to the scope or nature of the data security incident," the company added.
Hacking has become a major concern for retailers in the United States.
Target Corp said in December that some 40 million payment card records were stolen along with 70 million other customer records during a cyber attack over the holiday shopping season.
Target said last week that the security breach could have been more extensive than reported.
The biggest credit card breach at a U.S. retailer reported to date was an attack against TJX Cos, the parent of TJ Maxx and Marshalls in 2007. The company disclosed that data from 45.7 million payment cards had been stolen by hackers over 18 months.