Lear (NYSE:LEA - Get Free Report) announced that its board has approved a stock buyback plan on Thursday, September 24th, RTT News reports. The company plans to buyback $1.50 billion in outstanding shares. This buyback authorization authorizes the auto parts company to repurchase up to 25.7% of its shares through open market purchases. Shares buyback plans are usually a sign that the company's board of directors believes its shares are undervalu…