It doesn't really matter that much if he thinks or knows a stock is under or over valued if he also expects that bad valuation to be maintained for any significant length of time.
Stock prices are not rational and there is no consistent way to calculate the value of a company. An expensive media campaign that accomplishes nothing related to their business offerings and may even lose the company significant amounts of money can end up raising a stock price. And you also don't have unlimited time to try and wait out stocks which also have so many other random factors being thrown in over the years.
