“I don’t like assassination by categorization,” Lloyd C. Blankfein, the former chief executive of Goldman Sachs, said of Mr. Sanders in a recent interview with The Financial Times. Other finance executives, who felt similarly but were reluctant to go public with their own views for fear of alienating clients or employees, said they were relieved Mr. Blankfein spoke up.

Many Wall Street executives don’t think Mr. Sanders’s policies are sound. “Canceling all college debt will help relatively rich and high-earning university graduates, versus the money coming out of the pocket of everyone else, including those who never went to university and therefore earn less,” Jennifer Fan, a former hedge fund manager who now invests her own money, said of Mr. Sanders’s policies. “The ideas are just not good, the consequences aren’t well thought out.”

By contrast, Mr. Trump’s economic policies, which have rolled back regulations, slashed taxes and focused on job creation, have favored corporations and coincided with a booming economy. Yet many Wall Street moderates are loath to support him, too. The president’s tough immigration stance has rattled bankers and traders, many of whom travel widely and depend greatly on foreign-born employees to bolster their ranks. His apathy toward climate change, whose effects are increasingly driving investing and spending decisions, has concerned many. And even in an industry once known for its boorish behavior and treatment of women, Mr. Trump’s meanspirited rants toward the Federal Reserve chair, the late Senator John McCain, and scores of other prominent public figures have landed badly.

Still, Wall Street’s embrace of Mr. Biden could have downsides for the candidate. Hillary Clinton took in millions of dollars in campaign contributions from bankers and hedge fund managers. But during the 2016 election cycle, her private speeches to Goldman Sachs, including a remark that blaming the global banking system for the financial crisis was an “oversimplification,” drew scathing attacks from both Mr. Sanders and Mr. Trump, who argued separately that she was too beholden to Wall Street. Mitt Romney, who spent decades as a private-equity executive at Bain Capital before running for president in 2012, was attacked for the debt and layoffs his firm imposed on its investment companies during his tenure there.

Mr. Biden had already received Wall Street support early in the primary season. Both Jonathan Gray, the president of Blackstone, and Marc Lasry, the investor and big Democratic donor, co-hosted fund-raisers for Mr. Biden in Manhattan on Feb. 13. And Mr. Biden has taken in donations from the hedge fund manager Seth Klarman, Mr. Maitland and Stephen Scherr, the chief financial officer of Goldman Sachs.

Yet, on the campaign stump, Mr. Biden has invoked some of the same anti-elitist rhetoric that Mr. Sanders and Senator Elizabeth Warren have used to rile up Democratic voters. Speaking to a crowd in Los Angeles late Tuesday evening, as key Super Tuesday victories rolled in, Mr. Biden said, “Wall Street didn’t build this country, you built this country.” In his campaign literature, he has bemoaned the financial industry’s putting profits over workers and the widening wealth gap in America.

The policy implications of a Biden administration for financial executives are not entirely clear. Mr. Biden has said he will shore up the Affordable Care Act, the landmark health-insurance reform act he helped enact during the Obama administration, which would presumably preserve the private-insurance system while enhancing government-subsidized coverage. He says he will reverse the Trump tax breaks and raise taxes on investment gains. Like Mr. Sanders, he has advocated for a $15 minimum wage. But he lacks the sort of detailed policy papers that Ms. Warren, a perennial critic of Wall Street, has generated, and his message is more focused on hope and solidarity than it is on attacking the current economic infrastructure.