Powerful players in the business world have gravitated toward Nikki Haley, aware that she remains an underdog but beginning to believe she has a chance.Late last month, Nikki Haley, the former U.S. ambassador to the United Nations, got an unexpected call from Jamie Dimon, the chief executive of JPMorgan Chase. Mr. Dimon said he was impressed by Ms. Haley’s knowledge of policy details and her open-minded approach to complex issues raised in the Republican presidential race, according to a person familiar with what they discussed. Keep it up, he told her.He wasn’t the only business heavyweight to say so.In recent weeks, a group of chief executives, hedge fund investors and corporate deal makers from both parties have begun gravitating toward Ms. Haley and, in some cases, digging deeper into their pockets to help her.Her ascent in the polls and strong debate performances have raised hopes among Republicans hungering to end the dominance of former President Donald J. Trump that maybe, just maybe, they have found a candidate who can do so.“I’m a long way from making my mind up — something could change — but I’m very impressed with her,” said Kenneth G. Langone, the billionaire Home Depot co-founder, who has donated to Ms. Haley’s campaign and is considering giving more. “I think she’s a viable candidate. I would certainly like her over Trump.”Kenneth G. Langone, a co-founder of Home Depot, is part of a bipartisan group of chief executives, hedge-fund investors and corporate deal makers who have shown new interest in Ms. Haley. Kevin Dietsch/Getty ImagesMs. Haley’s fresh appeal to the moneyed crowd is coming at a critical juncture in the race, when positive buzz and steady cash flow are vital to a candidate’s survival. With less than eight weeks before the Iowa caucuses, Ms. Haley’s campaign and allied political committees need money to pay for travel, advertising, staff and a ground game to draw out potential voters.Some business leaders say they appreciate her focus on cutting taxes and government spending. Others praise her foreign-policy chops and her search for a winning Republican message on abortion rights, on which she has sought a moderate path but recently tacked to the right by saying she would have signed a six-week ban as governor of South Carolina.Most say they see her as a welcome alternative to Mr. Trump, whom they blame for inciting the violence of Jan. 6, 2021, for costing Republicans a Senate majority in last year’s midterm elections and for being too volatile as a commander in chief. They also prefer her to President Biden, whose economic policies and age many cited as a concern.“It’s invigorating to be truly excited by a candidate again,” said Jonathan Bush, the chief executive of a health-data startup and a cousin of former President George W. Bush. He hosted a virtual fund-raiser for Ms. Haley in early November.Mr. Bush, a Republican who voted for Mr. Biden in 2020 and for Gary Johnson, the Libertarian candidate, in 2016, said he had been struck by her knowledge and poise.“The topic that everyone is on is, ‘How do you beat Donald Trump?’” Mr. Bush said, “and she was careful to say, ‘Look, people will decide about him, but this is where I am on certain issues.’ And she rattled off some issues, related to our debt, related to our role in the world. But what you picked up was an electric energy,” he added, “that I think got this crowd really excited.”But even with Ms. Haley’s momentum, halting Mr. Trump’s seemingly inexorable march to the Republican nomination promises to be a slog. With a wide edge in national and early-state polls, the former president is running effectively as an incumbent, with legions of supporters prepared to vote solely for him.Several donors and advisers described two groups taking shape among the major, top-dollar donors:First, those who have yielded to the likelihood that Mr. Trump, however they may feel about him, will probably be the nominee, and have decided to stop funding potential alternatives. Second, those who believe that with enough financial resources and a savvy field operation, Ms. Haley could unseat him.Despite the long odds, her financial supporters say they see a path to victory.“There were people that don’t like Trump at all but were very skeptical that he could be stopped,” said Eric Levine, a Republican fund-raiser who leads the bankruptcy and litigation practices at Eiseman Levine Lehrhaupt & Kakoyiannis. “They now believe he can be stopped,” he said, pointing to Ms. Haley’s steady climb in the polls.Mr. Levine, who initially backed Senator Tim Scott of South Carolina, is co-hosting a Haley fund-raiser on Dec. 4. “His aura of invincibility is just peeled away completely,” he said.A spokeswoman for Ms. Haley’s campaign declined to comment.Polls show that Ms. Haley has gained traction against Gov. Ron DeSantis of Florida, who has held the No. 2 spot in national surveys all year. In Iowa, she has pulled nearly even with Mr. DeSantis, even as he has pursued an all-in strategy for that state. In New Hampshire, where she is in second place, she has been nearing 20 percent in polling averages.Her campaign said she pulled in $1 million in the first 24 hours after the last debate on Nov. 9, where she distinguished herself for her hawkish positions on Ukraine and Gaza and for her scathing dismissal of Vivek Ramaswamy, a rival she called “scum.”And while fund-raising numbers for the fourth quarter have not yet been released, interviews with about 20 financial and corporate executives suggest that more big checks will soon arrive.Ms. Haley’s $11.6 million war chest has already been bolstered by campaign contributions from wealthy Wall Street executives, including the fund manager Stanley Druckenmiller and the private-equity investor Barry Sternlicht.“I’m supporting Nikki because I think the nation needs to move on from the divisiveness and fear-mongering of the far left and right,” Mr. Sternlicht said. “I’m also opting in for a fresh face, a younger person who more accurately reflects the nation.”Timothy Draper, a venture capitalist in California, was an early backer, pouring $1.25 million into a super PAC supporting her. In recent weeks, he said, he has fielded interest from Democrats and Republicans and, notably, many women. “I think she can unify the country,” he said.Ms. Haley has mingled with Gary D. Cohn, the onetime Goldman Sachs president who served as Mr. Trump’s top economic adviser at the same time Ms. Haley was U.N. ambassador, and the investment banker Aryeh Bourkoff, who co-hosted a fund-raiser for her in Manhattan on Nov. 14.Her team is discussing policy with representatives for Kenneth C. Griffin, the billionaire hedge fund founder, on topics running the gamut from increasing students’ access to high-quality education to how to ensure a strong national defense, according to a person briefed on their discussions.Mr. Griffin recently told Bloomberg News that he was “actively contemplating” backing her, but he has not made up his mind, this person said.Students at Emmaus Bible College in Dubuque, Iowa, listening to Ms. Haley speak at a campaign event this month. She has risen in polls in Iowa, where Gov. Ron DeSantis of Florida has invested heavily. Ms. Haley’s backers, as well as some Republican observers, believe that if she can inch closer to Mr. DeSantis in Iowa or even outmaneuver him for second place, she could enter the New Hampshire primary election the next week with real momentum.If she could then reel in support from the state’s independent voters, some of them add, she could have a chance of beating Mr. Trump there.“There’s a possibility in the coming months to win New Hampshire,” said Mr. Bush, who is planning to form a political action committee to promote Ms. Haley to independent voters in the Granite State, not far from where he lives in Maine.Mr. Bush also plans to repeat his virtual fund-raiser to introduce her to new donors without asking her to spend unnecessary time working a cocktail party. (He said that he invited his Bush cousins to the November event, but that none of them attended.)An upset in New Hampshire could also move the needle during the Feb. 24 primary in Ms. Haley’s home state, South Carolina, where she was governor before serving in the Trump administration. She is polling second there, trailing the former president badly.The leanness of Ms. Haley’s campaign has become an asset. In the third quarter, her campaign spent $3.5 million, about 43 cents of every dollar it took in, a far lower rate than candidates like Mr. DeSantis as well as Mr. Scott, who dropped out this month.Some Wall Street executives, many of whom are focused on government spending and debt, note approvingly that Ms. Haley largely flies commercial.For some deep-pocketed donors, the openness to Ms. Haley stems from desperation.“I would take anyone not over 76 or crazy,” said Michael Novogratz, the chief executive of the cryptocurrency firm Galaxy Digital, a past Biden supporter who is now exploring both Ms. Haley and Representative Dean Phillips, the Minnesota Democrat who is mounting a last-ditch bid for his party’s nomination. Mr. Novogratz said that Mr. Trump was too divisive and that Mr. Biden was too old.Ms. Haley is someone he might support, he said, as is former Gov. Chris Christie of New Jersey.“Unfortunately,” he added as a caveat, “I don’t see either beating Trump.” More