Doosan Heavy Industries & Construction Co., South Korea\'s leading power equipment maker, said Thursday it plans to buy back shares worth 50 billion won (US$42.4 million) in a bid to boost its share prices. Doosan Heavy will buy back some 890,000 shares from Sept. 23 to Dec. 23, it said in a regulatory filing. Shares of Doosan Heavy were trading at 56,200 won on the Seoul bourse as of 2:00 p.m., up 0.18 percent.