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 Natera, a filing with the SEC revealed that on Thursday, EXECUTIVE CHAIRMAN Matthew Rabinowitz bought 219,820 shares of NTRA, for a cost of $28.74 each, for a total investment of $6.32M. Rabinowitz was up about 22.5% on the buy at the high point of today's trading session, with NTRA trading as high as $35.20 in trading on Monday. Natera is trading up about 2.5% on the day Monday. This purchase marks the first one filed by Rabinowitz in the past year.

And at ICU Medical, there was insider buying on Thursday, by Director George A. Lopez who purchased 25,835 shares for a cost of $172.91 each, for a trade totaling $4.47M. This buy marks the first one filed by Lopez in the past twelve months. ICU Medical is trading up about 2.6% on the day Monday. Lopez was up about 4.6% on the buy at the high point of today's trading session, with ICUI trading as high as $180.89 in trading on Monday.

For MarketNewsVideo.com, I'm Sayoko Murase.