As Dell shares hit a five-year low, there is one energetic buyer in the market, a bloke called Michael Dell.

Chief Executive Michael Dell has bought about $100 million worth of stock in Dell, making many wonder if he knows something that the rest of us don't. According to a regulatory filing the company made after the close of trading, Dell bought more than 4.5 million shares for $99.7 million in three separate deals from June 27th through to yesterday.

It means that he owns more than 250 million shares directly or indirectly, which is about 11 percent of the company. This does not include shares that he has options to buy.