As the saying goes, there are many possible reasons for an insider to sell a stock, but only one reason to buy -- they expect to make money. So let's look at two noteworthy recent insider buys.

On Thursday, Mattel's CEO, Ynon Kreiz, made a $1.01M purchase of MAT, buying 65,000 shares at a cost of $15.53 each. Kreiz was up about 7.7% on the purchase at the high point of today's trading session, with MAT trading as high as $16.73 at last check today. Mattel is trading up about 4.5% on the day Friday.

And at National Bank Holdings, there was insider buying on Wednesday, by John Steinmetz who purchased 24,200 shares at a cost of $41.41 each, for a total investment of $1.00M. National Bank Holdings is trading up about 1.6% on the day Friday.