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.

At Concentrix Corp (CNXC), a filing with the SEC revealed that on Friday, CEO Christopher A. Caldwell purchased 900 shares of CNXC, at a cost of $54.59 each, for a total investment of $49,131. Caldwell was up about 4.3% on the buy at the high point of today's trading session, with CNXC trading as high as $56.92 in trading on Wednesday. Concentrix Corp is trading down about 0.5% on the day Wednesday.

And at Central Securities Corporation (CET), there was insider buying on Friday, by Vice President Andrew J. O'Neill who purchased 800 shares for a cost of $40.13 each, for a trade totaling $32,104. Before this latest buy, O'neill purchased CET on 2 other occasions during the past year, for a total cost of $77,893 at an average of $35.80 per share. Central Securities Corporation is trading up about 0.3% on the day Wednesday. So far O'Neill is in the green, up about 2.9% on their buy based on today's trading high of $41.29.