DUBLIN (AP) — Irish betting company Paddy Power announced Thursday it is notifying hundreds of thousands of customers that most of their profile information was stolen in 2010, but hackers did not gain their credit card details or log-in passwords.

Paddy Power defended its four-year delay in reporting the biggest security breach in the company’s history by arguing that it didn’t know most of the details until much more recently. Online security experts said the fast-growing betting firm should have alerted its customers much sooner.