By Rober Frank, May 6, 2015, CNBC

Hillary Clinton is the favorite U.S. presidential candidate among millionaire voters and would win a head-to-head contest with former Florida Governor Jeb Bush, according to the third CNBC Millionaire Survey conducted in March that was released today.

The survey, which polls 750 Americans with a net worth of $1 million or more, found that 53 percent of millionaires would vote for the Democratic ex-Secretary of State, compared with 47 percent for the GOP presidential hopeful, in a hypothetical general-election match-up. Clinton had the support of 91 percent of Democratic millionaires, 13 percent of Republican millionaires and 57 percent of Independent millionaires. (Tweet this)

When asked about the broader field of candidates, Clinton got the most support, with 36 percent of millionaires. Jeb Bush came in second with 20 percent, followed by Senator Elizabeth Warren (D-Mass.) with 8 percent, and Governor Chris Christie (R-N.J.) with 7 percent.

Within the broader field, Republican candidates received a total of 49 percent of the vote, suggesting that the race could tighten as Republicans coalesce around a single candidate.