President Barack Obama, who campaigned hard against Trump, telephoned the Republican to congratulate him on his victory and invited him to the White House for a meeting on Thursday, the White House said in a statement. "Ensuring a smooth transition of power is one of the top priorities the President identified at the beginning of the year and a meeting with the President-elect is the next step," the White House said. Worried that a Trump victory could cause economic and global uncertainty, investors were in full flight from risky assets. Despite losing the state-by-state electoral battle that determines the US presidency, Clinton narrowly led Trump in the nationwide popular vote, according to US media tallies. Clinton did not immediately make a concession speech, instead sending campaign chairman John Podesta out to tell her supporters to go home.