As we come upon the close of the first quarter of 2013, most major equity indices around the globe are showing impressive gains, buoyed by continued monetary easing by central banks and hopeful signs of economic resurgence. While investors will likely look for confirmation in upcoming earnings reports, the recent negative preannouncement from economic bellwether FedEx (FDX) should serve as a reminder that profit margins are near all-time highs and could represent a significant hurdle for stocks. Read more