[zorga]

70% is extremely high, you can easily get rich with a 51% advantage and making enough small bets to invoke the law of large numbers.

[lambdasquirrel]

That, and depending on the companies they got data on (i.e. any number of widely traded stocks with large market caps), they could have had a LOT of volume to play with. This is a big deal and it's mind-boggling that the breach happened.