Activist investor Carl Icahn has his lifted his stake in Navistar International Corp. (NYSE:NAV) to roughly 12 percent, a day after the truck manufacturer posted a surprise quarterly loss and slashed its earnings guidance yet again this year. A regulatory filing showed that the billionaire investor acquired a total of 883,200 shares of Navistar for $24.44 apiece to take his stake to 8.1 million shares. [More...]