The Globe and Mail reports in its Tuesday, July 21, edition that share buybacks are typically used by companies as a strategy to enhance shareholder returns. The Globe's regular guest columnist Ted Dixon writes that when insiders buy during an active buyback program, they reinforce the idea that the stock is undervalued. When insiders are selling in size while the company repurchases shares, the message is less encouraging. It can point to declining growth opportunities or a rising risk environment. Industrial stocks have been hitting Mr. Dixon's insider screens recently, and that includes Canadian National Railway. During the first six months of the year, four directors at the railway reported acquiring 9,400 shares in the public market at an average price of $139.38, representing just over $1.3-million in purchases. Over the same period, Canadian National Railway reported buying back almost $1.3-billion worth of stock. The 8,886,156 shares were purchased at an average price of $146.10. The railway will release second quarter results before the market opens on July 24.