Dixons Carphone Plc said a cyberattack affected nearly 6 million payment cards as hackers sought unauthorized access to customers' personal data.
The hack targeted one of the processing systems of Currys PC World and Dixons Travel stores. "We have no evidence to date of any fraudulent use of the data as result of these incidents", the company said.
Dixons Carphone will be contacting the 1.9 million people who have had their personal data breached and says it has already plugged the hole in its systems.
It admitted non-financial personal data, such as name, address or email address, was accessed but it again insisted that it had seen no evidence of any fraud at this stage.
The company's shares lost 5% of their value when trading began on Wednesday morning shortly after the disclosure.
Dixons Carphone chief exec Alex Baldock apologised to customers for the inconvenience, adding (as is standard in post-breach statements) that the company takes security seriously.
Dixons Carphone said it had immediately notified the relevant card companies so that they could protect customers.
It is investigating the hacking attempt, which happened previous year.
Signs display the logo of Dixons Carphone at the company headquarters in London, Britain August 1, 2017. Paul German, CEO at Certes Networks, commented: "Despite the well-publicised Target data breach, it seems that other retailers are still not adopting appropriate cybersecurity strategies". But around 105,000 non-EU issued payment cards were compromised.
The company has launched an investigation into the incident and is said to be engaged with cyber security experts.
"The NCSC website offers advice to organisations about ensuring their online security is as robust as possible, including guidance on protecting bulk personal data from cyber attack", they added. Baldock added that Dixons Carphone has also "added extra security measures" to its systems.
ELECTRONICS RETAILER Dixons Carphone (DCP) has announced a breach in its systems that are said to have exposed the personal information of up to six million people.