The stock market is not really worried about Sen. Bernie Sanders' rise in the Democratic primary, private equity billionaire David Rubenstein told CNBC on Wednesday.
"I think the markets generally do not think that Bernie Sanders is likely to be president of the United States," the Carlyle Group co-founder said on "Closing Bell." "Now that could be wrong, and sometimes the markets are wrong of course."
But at the moment, Rubenstein said the Vermont senator is not being viewed as a strong threat to unseat President Donald Trump in November, should Sanders win the Democratic nomination.
Part of the reason is because it remains very early in the nominating process, Rubenstein pointed out. Iowa and New Hampshire are the only two states to have held nominating contests.
Rubenstein, who worked in the White House under former President Jimmy Carter, said the New Hampshire primary is not exactly an automatic indicator that a candidate will go on to become president.
Sanders narrowly won the Democratic primary in New Hampshire on Tuesday night, edging out former South Bend, Indiana, Mayor Pete Buttigieg and Minnesota Sen. Amy Klobuchar.
Rubenstein said Carter was the last non-incumbent president to win the New Hampshire Democratic primary who would go onto to win the general election.
"The history of New Hampshire picking people who go on to be president of the United States, at least for the last half-century, hasn't been wonderful," he said. "So I don't think the markets are probably that unduly worried about Bernie Sanders."
Rubenstein has previously donated to both Democratic and Republican candidates and causes. But it's more more than a decade since he's made a political contribution.
Rubenstein's comments about how the market views Sanders are shared by others across Wall Street.
Some believe that Sanders, a self-described democratic socialist, would have difficulty beating Trump in a head-to-head election. Therefore, as Sanders rises in the polls and wins nominating contests, it increases the likelihood that Trump, who is widely considered a positive for the market, would win re-election.
Plus, Rubenstein pointed out that presidents usually win a second term when they have a strong economy. Rubenstein has been complimentary toward Trump's economic policies.
"Presidents lose ... when they're running for re-election when they have a recession," he said. "Jimmy Carter. Gerald Ford. George Herbert Walker Bush."
Rubenstein also said he believes the market can continue to move higher, even though some are raising concerns about whether stocks are overbought.
Stocks closed Wednesday at fresh all-time highs, with investors looking past concerns about the coronavirus' impact on the global economy.
Health care stocks are generally considered to be at risk under a potential Sanders' presidency. Sanders wants to abolish the private health care industry and create a single-payer, Medicare-for-all system.