Billionaire Clinton supporter says Trump is 'not a good investment'

Trump's 'not a good investment': Simons

James Simons, a major donor for the Democratic party and its presumptive nominee Hillary Clinton, told CNBC's "Squawk on the Street" that if you compare the presidential candidates using the Sharpe ratio, presumptive GOP nominee Donald Trump is "not a good investment."

The Sharpe ratio is a way of measuring average return while accounting for risk or volatility.

"Now even if those two candidates had the same expected return — which I doubt — but even if Trump's was as good as Hillary's, his volatility is so enormous that his Sharpe ratio is terrible," Simons said.

"So as an investment, Trump is not a good investment, no matter what you might think of his potential return. He's just a wild man," he said.

Simons said that he is a supporter of Clinton, who he said would "make a fine president." When asked what a Trump presidency would mean for the U.S. outlook, Simons said "it wouldn't be good for the country."

"I can't tell what the man will do because he's so erratic. As a businessman, he was apparently pretty sleazy. I just can't predict and maybe it would turn out OK, who knows," he concluded.

Hope Hicks, a spokeswoman for Trump, did not immediately respond to CNBC's request for comment.