The International Monetary Fund said on Wednesday, the global economy faces a growing risk from big financial market bets that could quickly unravel if investors get spooked by geopolitical tensions or a shift in U.S. interest rate policy. The IMF, an institution based in Washington that is the world's premier watchdog for financial and economic stability, said in a report it still expects economic growth will pick up in the second half of 2014 after a rough start to the year.