When insiders buy shares on the open market, their companies could enjoy bullish times ahead. Corporate insiders often have the inside track on their company's prospects, and many of them get paid largely in stock options or restricted shares. Besides, insiders probably wouldn't risk plowing too much of their own money into their own company's stock -- reducing their portfolio's diversity, and increasing its risk -- unless they thought the stock might rise.

With that in mind, I screened for companies where at least one insider made an open-market buy in the past 30 days. These eight materials stocks made the list:

Security

Net Number of Buys

No. of Shares Bought

Total Value

Market Cap 
(in Millions)

Texas Industries (NYSE: TXI) 4 724,288 $28,750,000 $1,130
Valhi (NYSE: VHI) 10 136,305 $6,690,000 $7,162
Kraton Performance Polymers (NYSE: KRA) 3 21,200 $1,090,000 $1,275
Titanium Metals (NYSE: TIE) 1 49,525 $875,000 $3,422
EnPro Industries (NYSE: NPO) 1 2,250 $101,000 $1,026
Esterline Technologies (NYSE: ESL) 1 1,235 $100,000 $2,503
Martin Midstream Partners (Nasdaq: MMLP) 4 706 $27,000 $798
Handy & Harman 1 1,000 $14,000 $219


Source: Capital IQ, a division of Standard & Poor's, as of July 21.

When it comes to the number and total value of insider open-market buys, more can be better; I've sorted this table accordingly. Insiders at Texas Industries made open-market purchases worth almost $29 million, while a Handy & Harman insider spent a much lesser $14,000 on open-market buys. Both are bullish signs, but the Texas Industries purchase looks more promising. Texas Industries and Kraton Performance Polymers are repeats from when I ran the screen a month ago.

Foolish takeaway
Insider buying signals that someone who should be in the know is betting that the stock will rise. You can use this list of recent insider purchases as a starting point for further research -- or as a reason to make a contrarian play.

Are these insiders right? To help you find out, The Motley Fool recently introduced a free My Watchlist feature. You can get up-to-date news and analysis by adding companies to your Watchlist now:

Fool contributor Cindy Johnson does not currently own shares of any stock in this story. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.