A suit contends that the defendants failed to properly encrypt data, then "intentionally, willfully and recklessly" allowed an untrained individual to access the information.
Public companies now must disclose known or potential cyber incidents if they would make investment in the company "speculative or risky," according to a document.
Sony's PlayStation Network again has been hit by hackers, but the limited damage that resulted could point to strides being made by the electronics giant.
Three unencrypted backup tapes containing the personal information of more than a million and a half individuals have gone missing from Nemours, a children's health system in Wilmington, Del.
While TD Ameritrade maintains that no identity theft resulted because of a 2007 breach, it has decided to compensate customers "in the interest of helping ease" their concerns.