I was just thinking about something today. Suppose that someone who was strongly tied to a company both in terms of name and in terms of stock (such as Bill Gates of Microsoft or Sergei & Larry of Google) decided to dump all of their stock in their company on one day, for no apparent reason. Presumably, this would cause investors to lose lots of confidence in the stock, and the price would fall tremendously. Would that person be allowed to buy back the stock that they sold in addition to more than they originally owned? Something like cornering the market, only not in regards to a commodity.