Market Watch - Hillary Clinton’s presidential campaign will get a boost from billionaire investor Warren Buffett next month. Clinton will campaign in Omaha, Neb., on Dec. 16 with the help of Buffett, the Omaha-based investor. The Omaha World-Herald writes the visit by the front-runner for the Democratic presidential nomination is an effort to organize grassroots support before the state’s Democratic caucuses. Clinton is expected to talk about tax reform with Buffett, one of her outspoken supporters. Nebraska Democrats hold presidential caucuses on March 5.