Republican presidential front-runner Donald Trump has turned the GOP's relationship with Wall Street on its head. Trump has vowed to get rid of trade deals supported by big business. He's threatened to default on U.S. debt, and he wants to raise tariffs on Chinese goods by 45 percent. He's accused hedge funds of "getting away with murder" and called Wall Street bankers "fat cats."

Business leaders have heard him loud and clear -- and they want to keep him out of the White House.

According to a survey by Fortune, Fortune 500 CEOs broadly support Democratic front-runner Hillary Clinton over Trump, with 58 percent wanting her in the Oval Office compared with 42 percent who prefer Trump. For years, the GOP has been considered the party of big business, but Trump's policy proposals have flipped that script.

The survey found CEOs disapproved of Trump's anti-trade rhetoric and calls to increase, not tear down, trade barriers. Most Fortune 500 firms -- including Walmart, Exxonmobil, Chevron, and Apple - do significant amounts of business outside of the United States and want that process to be as smooth as possible. Members like Google and Facebook also support the Trans-Pacific Partnership, a massive Pacific trade deal covering 40 percent of the world's economy. Trump has called it "horrible" and vowed to tear the pact up.

Clinton, who championed the deal while secretary of state, has now come out in opposition as well.

The tally also found growing concern about Trump's policy toward immigrants -- he wants to build a wall along the U.S. border with Mexico and deport 11 million undocumented immigrants from the country. The National Immigration Forum, the Center for American Progress, the Migration Policy Institute, the Cato Institute, and the American Action Forum have determined these changes would cost at least $166 billion. The American Action Forum also found that rounding up and deporting all undocumented immigrants could shrink the U.S. economy by 2 percent in one year.

There are also worries about Trump's grasp of public finance. This includes the billionaire businessman's plan to deliberately default on U.S. debt, which would make every asset in the world riskier and more volatile because investors could no longer retreat to the safe haven of U.S. bonds. The price of borrowing would go up across the board. Credit would disappear, as people and banks would hoard their cash. It could make the 2008 crash -- caused by the quick implosion of mortgages, also thought to be the safest of investments -- look like a walk in the park.

It's not as if CEOs expressed enthusiasm about the policies put in place by President Barack Obama; 69 percent said increased regulation put in place while Obama was in office are one of the top three or four challenges facing their company. But grappling with a choice between Clinton -- a known commodity with reasonable, if not popular, policies that impact Wall Street -- and Trump -- whose policies threaten to undermine the global financial order -- leaders of the world's largest businesses back the safer option.