International Paper announced its board of directors has authorized management to acquire up to $1.5 billion of additional shares of the company’s common stock to supplement the $1.5 billion share repurchase program authorized in September 2013. The company intends to continue to repurchase such shares in open market repurchase transactions.   “Today’s $1.5 billion expansion of our share repurchase program reflects our continued confidence in International Paper’s strong, sustainable free cash f...