Last week, the European PlayStation Network issued a mandatory password reset after some "irregular activity" on some users' accounts. They claimed there was no security compromise on their end of things.

Today, a similar situation seems to have hit the US PlayStation Network, with a moderator posting a mere warning on the PlayStation forums that urges users experiencing sign-in issues to reset their password.
"If you are getting an error that your PSN account password is incorrect, you may need to reset it. We routinely monitor for irregular activity, and if such activity is detected, we may sometimes reset passwords of affected SEN accounts to protect consumers and their account information."

Some users in a Reddit thread about this are saying they've been hit with some hefty fraudulent charges as a result of this potential security issue. Similar to what happened with the Xbox 360 security scare, it seems as though most of these fraudulent charges are for FIFA points. It does not matter if you own FIFA or not.