According to the company, the JokerStash hacker group, which recently announced the hacking of data and put up 125,000 records for sale, was behind the crime.
"In cooperation with several financial organizations, we have confirmed with a high degree of confidence that the compromised records were stolen from customers of Saks Fifth Avenue and Lord & Taylor stores. We estimate the window of compromise to be May 2017 to present," the company reported.
"The current hacking attack is amongst the biggest and most damaging to ever hit retail companies," the cybersecurity experts said.
The report also recalled that hackers from the JokerStash group had earlier hacked data from customers of such chain stores as Whole Foods, Chipotle, Omni Hotels & Resorts and hotels of the Trump Hotels chain, which was established by the incumbent US president Donald Trump.