RE:news on investigation They didn't have an information leak, but for Sept. 6 they probably knew well that Viceroy had a crazy attack report ready to release, so I would imagine that narrows down the list of suspects... Most brokers would require an account to actually have 700,000 shares in it, to be able to send in a sell order for that quantity, or a borrowed amount for a short sale arranged. Hopefully regulators will continue to investigate because the whole system breaks down if some are allowed to make and cancel whatever orders they want to send in. Either that or robotic trading systems need improvement to be able to differentiate real orders from nonsense.