Donald Kohn, vice chairman of the U.S. Federal Reserve, mode

UNITED STATES - JUNE 05: Donald Kohn, vice chairman of the U.S. Federal Reserve, moderates a panel discussion at the Journal of Money, Credit, and Banking Conference on Financial Markets and Monetary Policy in Washington, D.C., U.S., on Friday, June 5, 2009. Janet Yellen, president of the Federal Reserve Bank of San Francisco said at the conference that policy makers need to be prepared for "substantial shocks" and that rising Treasury yields may be a "disconcerting" signal of inflation fears. (Photo by Brendan Hoffman/Bloomberg via Getty Images)