If someone steals (maybe by logging in with stolen credentials) from a person's retirement account, is that money gone, or are accounts insured against theft and hacking?
Edit: it sounds from the comments that if someone were to "hack" my account and transfer all of my retirement savings to their account, I'd be screwed. Same goes for all of you, I guess. Why isn't this more discussed / regulated? All it takes is a trojan / digging through the trash / some social engineering to come up with a mother's maiden name and a password.