CNBC's "Millionaire Survey," which in March surveyed 750 people with $1 million or more in investable assets, found that in a head-to-head contest between Clinton and Trump, 44 percent of millionaires would vote for Clinton in November, compared with 31 percent for Trump.
Clinton also has a more committed voter base among millionaire voters. When asked to rate their support level for candidates — with zero being "no support at all" and 100 being "strongly support" — Clinton received a total rating of 38, while Trump earned a 28. Among Democrats, Clinton earned a support rating of 78, while Trump rated only 50 among Republicans.
Yet 15 percent of millionaires remain undecided on their vote in November. And millionaire support for Trump — typically viewed as the favorite of blue-collar workers — is growing, with his share of millionaire voters more than tripling over the past six months. Last fall, CNBC's Millionaire Survey showed that only 9 percent supported Trump in a crowded field of Republican candidates.