Janet Yellen, vice chairman of the U.S. Federal Reserve, speaks during a panel session at the Annual Meetings of the International Monetary Fund (IMF) and the World Bank Group in Tokyo, Japan, on Wednesday, Oct. 10, 2012. Yellen said Fed asset purchases that boost U.S. economic growth would benefit the world, with emerging nations having the tools to manage capital flows. Photographer: Kiyoshi Ota/Bloomberg via Getty Images