NEW YORK (AFP) - At first glance, Donald Trump is everything Wall Street likes - a billionaire whose real estate empire has provided huge business for banks, and whose luxury towers house the rich and famous.
But his surprise success in the fight to win the Republican nomination for the US presidency has sent a chill over the heart of American capitalism.
The list of fears runs long: a president Trump could launch a trade war with China; he could increase taxes on the rich; he could interfere with the Federal Reserve over monetary policy; the White House's relations with Congress could break down completely.
"He scares the markets. He is a big uncertainty," said Greg Valliere, chief strategist for Horizon Investments. "The market does not like uncertainty."
Businesses are disconcerted by the off-the-cuff comments Trump renders about crucial business and economic issues almost daily since hitting the campaign trail last year.
On one side, he has denounced huge salaries for chief executives, the greed of bankers and tax advantages that benefit wealthy Wall Street fund managers.
He has menaced the huge population of undocumented immigrants that effectively keeps up the supply of low-wage workers for US businesses.
He attacks China and Japan for manipulating their currencies for trade advantage and threatens to start a trade war with China. At the same time, he has declared his opposition to two huge free-trade accords spanning the Pacific and Atlantic oceans.
He has even leveled attacks at the titans of US businesses such as Ford and Apple because they manufacture outside the country as well as inside.
But on the other hand, Trump courts US industry leaders with promises of business tax cuts. He also praises the skills of fellow billionaire Carl Icahn, one of Wall Street's most successful activist investors, who stands out as one of Trump's few vocal backers on Wall Street.
"He doesn't fit into any particular economic mold, he's not a traditional conservative like Ronald Reagan," said Mark Perry of the American Enterprise Institute, a conservative think tank.
"His platform is really kind of a mixed bag of populist and isolationist types of policies that, he knows, will appeal to a lot of uninformed people."
Former White House nominee Mitt Romney, who ran the prominent investment house Bain Capital before entering politics, gave voice to the finance community's worries Thursday, warning that under Trump "the country would sink into a prolonged recession."
"A business genius he is not."
Mr Perry pointed to one of Trump's more obvious "hypocrisies" - having his own Donald J Trump brand menswear collection manufactured in China even while blasting that country for cheap labor.
Chris Low, chief economist at FTN Financial, said some of his clients appreciate Trump's position on cutting corporate taxes. But they also fear he could spark a trade war with China that could harm US businesses.
"We live in a globally connected economy," Mr Low said.
So far, however, markets have not reacted to Trump's strong lead in the Republican White House race. Fund managers remain uncertain about his chances against the likely Democratic nominee, former secretary of state Hillary Clinton, Mr Low said.
"Trump's success moving forward is likely to bring increased volatility," David Lafferty of Natixis Global Asset Management predicted.
Among bankers, the sentiment is generally anti-Trump. Goldman Sachs chief Lloyd Blankfein last September pointed to the US president's power to unleash a nuclear weapon.
"The image of Mr Trump with his finger on the button blows my mind," he said.
But most bankers contacted by AFP would not speak openly about their disdain for Trump, worried about possible reprisals.
"He is crazy, he has crazy policies," one prominent banker said.
"He does not know how to run a business," another said. "How can he run a country?"
Still, even as he weathered four corporate bankruptcies, Trump has amassed a fortune mainly in real estate estimated at US$4.5 billion.
"We sometimes forget that underneath all the things that he does - the talking, the hair, the TV shows - he does know how to build, and he does know how to do that in an extremely efficient and economical way," said Gwenda Blair, author of "The Trumps," a book about the tycoon and his family.
Whatever it feels, Wall Street doesn't have a clear alternative, with polls showing Trump's top Republican rivals, Senators Ted Cruz and Marco Rubio, both too weak to overcome his lead in the primary race.
Some in the traditionally heavily Republican finance community are prepared to turn their support to Democrat Hillary Clinton in the November election, if the other choice is Trump.
"The market is nervous about him," Valliere said.
Clinton is "the devil you know," he added. "The market will live with her."