Name: Ben Bernanke
Ben Bernanke's words and deeds have had a massive effect on interest rates. His easy-money policies, for example, helped mortgage rates drop to near-historic levels in 2013, driving a boom in refinance activity across the country. Then his lack of substantive communication on the fate of the Fed's quantitative easing program helped drive rates up a full percentage point over the summer, strangling the refinance boom. Then his decision, along with the rest of the Fed's policy-making board, to leave the program in place helped rates drop again.