Adidas, the German sports apparel and equipment company, has revealed that its websites were the target of a "sophisticated, criminal cyber attack" last week.
It insisted, however, that there is no evidence that any consumer data has been compromised.
Adidas discovered the attack on 3 November and took down the affected sites, including adidas.com, reebok.com, miCoach.com, adidas-group.com and various local eCommerce shops, while it carried out its investigations.
The company has since implemented additional data security measures, and while the majority of the websites were restored yesterday, a spokesperson for Adidas said that it is still working on getting adidas.com and miCoach.com back online.
With miCoach.com, it is installing a planned update before making the website live again.
"Nothing is more important to us than the privacy and security of our consumers' personal data.
"We appreciate your understanding and patience during this time," the company said in a statement.