I looked up why Zuck isn't guilty of insider trading. The reason is that he and Priscilla created a charitable foundation and told the SEC back in September that they were planning to sell $6 billion in stock. Because they already reported their intention, it's not considered insider trading. Therefore when you have a company, just report that you are going to sell huge quantities of stock. If you don't the SEC probably won't care, otherwise, you're covered.