In the weeks since Zohran Mamdani’s stunning victory in the Democratic mayoral primary, some corporate and finance leaders have predicted an exodus of wealthy investors from New York City. They have called him a Marxist and an out of touch idealist, and have warned of rough times ahead for the city if Mr. Mamdani, a democratic socialist, wins the general election in November.

On Tuesday and Wednesday, leaders on Wall Street and across the business world will have an opportunity to confront Mr. Mamdani directly in meetings with the Partnership for New York City, a consortium of 350 members representing banks, law firms and corporations.

The meetings were requested by Mr. Mamdani, a Queens assemblyman who says he wants to work with the business community. Mr. Mamdani has recently moderated some of his stances that have generated the most controversy as he shifts his focus to the general election. Tuesday’s meeting will take place behind closed doors with no news media present, and more than 100 executives are expected to attend.

The Partnership’s board is a who’s who of powerful business leaders including Henry Kravis of KKR, Rob Speyer of Tishman Speyer and J.P. Morgan’s chief executive, Jamie Dimon, who last week publicly criticized Democrats for “falling all over themselves” to support Mr. Mamdani’s policies including city-run grocery stores and a rent freeze on rent-stabilized apartments. “There’s the same ideological mush that means nothing in the real world,” Mr. Dimon said at an event in Europe.

But as much as corporate leaders express reservations about Mr. Mamdani’s left-leaning policies, some of them are taking a pragmatic approach to the upstart candidate, who is leading in polls.

Kathryn Wylde, the Partnership’s chief executive who had a frosty relationship with the city’s last progressive mayor, Bill de Blasio, has been open to working with Mr. Mamdani.

“His policies sound similar to Bill de Blasio’s, but he’s a lot more pleasant to be around,” Ms. Wylde said.

For his part, Mr. Mamdani said he was open to listening to business leaders.

“For our city to succeed, it will take all of us,” Mr. Mamdani said at a rally on Monday in Manhattan. “That includes those business leaders — where we have a shared interest in this city and this city’s success. I’m excited to share my plans to that end and to work with them to achieve that success.”

Already this week, Mr. Mamdani has been sharing his plans with business leaders and seeking to clarify prior statements that have worried some of them. On Monday, he met with Black executives in a meeting at the Whitby Hotel organized by Charles Phillips, a private equity executive.

The executives grilled Mr. Mamdani on a range of issues like his plans for corporate taxes and whether he would keep Jessica Tisch as police commissioner. While Mr. Mamdani would not commit to keeping Ms. Tisch, he did reiterate his openness to doing so, Mr. Phillips said.

According to Mr. Phillips, Mr. Mamdani backed away from previous comments that billionaires shouldn’t exist, saying the question had caught him off guard, and it wasn’t a debate he wanted to focus on.

And the candidate signaled that he wanted to enact a rent freeze on rent-stabilized apartments during his first term, but that it might not be permanent, said Mr. Phillips, who has been an ally of Mayor Eric Adams.

“People in the room, while they still challenged him, they respected the fact that he wanted to engage directly,” Mr. Phillips said.

Mr. Phillips, who sits on the board for the Partnership for New York, plans to attend the group’s meeting with Mr. Mamdani on Tuesday.

Mr. Mamdani’s surprise victory in the primary over former Gov. Andrew M. Cuomo, a business-friendly candidate, set off a cascade of alarms last month. A few business executives even warned that Mr. Mamdani’s mayoralty could lead to some investment firms moving from the city.

Many wealthy Democrats had backed Mr. Cuomo’s campaign. But even as the former governor announced on Monday that he would run in November as a third-party candidate, his resounding loss last month did not inspire confidence on Wall Street that he can win in the fall. Mayor Adams’s candidacy has been hampered by the federal corruption case against him, which was eventually dropped by the Trump administration, and his waning popularity among voters.

While some business leaders have begun to understand Mr. Mamdani’s appeal with voters, they are not convinced about the feasibility of his policies, in particular, freezing the rent on rent-stabilized apartments and plans to raise both income and corporate taxes.

“There is a real concern about how his policy proposals, despite their intended political appeal, would impact New York’s competitiveness and quality of life given the challenges of the last several years and where the city stands in Washington’s eyes,” said Ed Skyler, who worked as a deputy mayor for Michael R. Bloomberg and is now a senior executive at Citigroup.

Mr. Skyler said he planned to attend Tuesday’s Partnership meeting.

Business leaders have raised alarm about mayors before. They assailed Mr. de Blasio in an open letter in 2020, criticizing his handling of public safety and the city’s recovery from the pandemic. Mr. Mamdani told The New York Times that Mr. de Blasio was the best mayor in his lifetime and praised his universal prekindergarten policy; they share some policy priorities, including wanting to raise taxes on wealthy residents.

In Mr. Mamdani’s meetings with the Partnership on Tuesday, he is set to speak with executives generally, and on Wednesday they will discuss the technology sector. Ms. Wylde said Mr. Mamdani reached out to the group after he won the primary. Ms. Wylde and Mr. Mamdani discussed setting up meetings, and he asked which executives he should reach out to, she added.

This week’s meetings with the business community could be critical for Mr. Mamdani. Even if he cannot manage to win over their enthusiastic support, it could help determine whether the city’s corporate leaders — and some of its biggest political donors — grudgingly accept Mr. Mamdani’s rise or wage an expensive battle to stop him.

The corporate group will meet with Mayor Eric Adams on Thursday, according to Ms. Wylde and a representative for Mr. Adams’s campaign. The group met with Mr. Cuomo in May.

Mr. Mamdani has other skeptics to win over. He said at the rally on Monday that he was also looking forward to meeting with Representative Hakeem Jeffries, the House Democratic leader from New York, and that he wanted to work with him to help win back the U.S. House for Democrats.

Mr. Jeffries has not endorsed Mr. Mamdani in the general election, diverging from some other Democrats in Congress. Mr. Jeffries had said that he had concerns about Mr. Mamdani’s refusal to condemn the term “globalize the intifada.”

Mr. Mamdani sidestepped a question from a reporter at the rally about that term and said he wanted to work with Mr. Jeffries to oppose President Trump’s agenda. As for his meetings with business leaders, Mr. Mamdani said that he would keep an open mind.

“I go into each of these meetings knowing what I know, knowing what I believe and interested in what I can also learn from each and every one of the people who have made the city what it is,” he said.

Jeffery C. Mays contributed reporting.