"The three were charged two years ago for a 2006 scheme in which they allegedly hacked into online brokerages or created new accounts using stolen identities, then bought and sold stocks in order to manipulate prices to their benefit.
They hacked into more than 60 accounts in nine brokerage firms, including ETrade and TD Ameritrade, according to authorities. One firm lost more than US$2 million because of the scam.
The men allegedly drove up prices of low-volume stocks they owned, such as Acordia Therapeutics, Pacel and IGI, by buying shares with the hacked accounts, then dumping the stocks before the price dropped, authorities said. In October 2006, they also manipulated the price of near-worthless "put" options for Google, which gave buyers the option of selling Google stock for $240 (about half its value at the time), authorities said." - PCworld
I was actually just chatting about this exact thing the other day and how easy it would be for an attacker to do. Had they really been organized they could have done some real damage. This is the kind of 'hacking' that actually worries me. Imagine doing this to manipulate OIL stock prices....