Mario Draghi

Mario Draghi led the European Central Bank from 2011 to 2019, right through the eurozone debt crisis. In July 2012, with markets betting the euro might break apart, he said the ECB would do "whatever it takes" to preserve it. Three words, and bond markets that had been bleeding for months began to calm down.

Under him the ECB pushed rates below zero and launched large-scale quantitative easing. He later served as Italy's prime minister. Traders still use him as the example of how much a central banker's words alone can move markets.