Michael Bloomberg, the billionaire former mayor of New York City, has told his aides to draw up plans for an independent campaign for the U.S. presidency, the New York Times reported on Saturday.

Bloomberg has advised friends and associates that he would be willing to spend at least $1 billion of his own money on a campaign for the November 2016 election, the Times said, citing sources briefed on the former mayor's thinking.

Bloomberg, 73, has given himself an early March deadline for entering the race, the Times reported, after commissioning a poll in December to see how he would fare against Donald Trump and Hillary Clinton, the current Republican and Democratic frontrunners respectively.

No independent has ever won a U.S. presidential election. But Bloomberg, who has close Wall Street ties and liberal social views, sees an opening for his candidacy if Republicans nominate Trump or Texas Senator Ted Cruz and the Democrats nominate Vermont Senator Bernie Sanders, the Times said.

Bloomberg served as mayor of New York City from 2002 to 2013. He switched his party affiliation from Republican to independent in 2007.