Donald Trump holds financial documents at his campaign announcement in June. He had said he didn't need donors because he could pay for his campaign himself, but he recently said he'd be open to people "investing" in his campaign. Christopher Gregory/Getty Images hide caption

itoggle caption Christopher Gregory/Getty Images

U.S. Secretary of State John Kerry talks to U.S. Secretary of Energy Ernest Moniz during Iran nuclear deal negotiations. Carlos Barria/AP hide caption

itoggle caption Carlos Barria/AP

J. Russell George, Treasury inspector general for tax administration (from left), Acting IRS Commissioner Steven Miller and former IRS Commissioner Douglas Shulman before they testified to the Senate Finance Committee in 2013. Win McNamee/Getty Images hide caption

itoggle caption Win McNamee/Getty Images

Republican presidential hopeful Donald Trump in front of his campaign plane in Laredo, Texas, last week. LM Otero/AP hide caption

itoggle caption LM Otero/AP