Microsoft is joining Facebook, Google and Yahoo on the list of companies that notify users when they’ve been targeted by state-sponsored hackers, inspired in part by charges that it failed to notify more than 1,000 victims in the past.

“We already notify users if we believe their accounts have been targeted or compromised by a third party, and we provide guidance on measures users can take to keep their accounts secure,” the company said in a blog post on Wednesday. “We’re taking this additional step of specifically letting you know if we have evidence that the attacker may be ‘state-sponsored’ because it is likely that the attack could be more sophisticated or more sustained than attacks from cybercriminals and others.”