With a leftist New York City politician appearing likely to be the Democratic mayoral candidate for the U.S.’ largest city, business interests are melting down over the prospects of his tax-the-rich platform aimed at improving basic services.

Zohran Mamdani, a 33-year-old assemblymember from Queens, took a commanding lead in the city’s Democratic primary Tuesday after running a campaign relentlessly focused on the cost of living and suggesting city-run groceries and free buses and child care. For the city’s 1% and its business elite, it’s a five-alarm fire.

“The reaction of the business community to the victory of a member of the Democratic Socialists is a combination of surprise and deep concern,” Kathryn Wylde, CEO of the Partnership for New York City, told Fortune via email. Because very few have met him, “their views are defined by his campaign rhetoric and the negative ads cast against him,” she said.

Billionaire hedge-fund manager Bill Ackman offered to bankroll someone, anyone, who would run against Mamdani, implying his mayoralty would spur a flight with the ultra-rich. “If 100 or so of the highest taxpayers in my industry chose to spend 183 days elsewhere, it could reduce NY state and city tax revenues by ~$5-10 billion or more, and that’s just my industry. Think Ken Griffin leaving Chicago for Miami on steroids,” he posted on X Thursday.

John Castimatidis, the owner of the grocery chain Gristedes, floated moving his corporate offices to New Jersey for the duration of Mamdani’s term, while financial analyst Jim Bianco accused New York of “electing to commit suicide by Mayor.” Governor Kathy Hochul, who has positioned herself as a pro-business moderate, preemptively nixed the idea of tax hikes, which the state would need to approve, saying, “I don’t want to lose any more people to Palm Beach.”

Talk is easy, moving is hard

Is New York City at risk of a billionaire exodus? History suggests no.

This isn’t the first time Wall Street mouthpieces and disgruntled business owners threatened to up and leave over a progressive mayor-elect. In 2013, Bill de Blasio won the mayoralty on a tax-the-rich platform, spooking high-income New Yorkers, but De Blasio met with Manhattan industry leaders, like former Goldman Sachs CEO Lloyd Blankfein and Rupert Murdoch, to win over the elites. The tycoons stayed, and so did Wall Street’s inhabitants. De Blasio, meanwhile, implemented a universal pre-K program that has proved to be an economic game changer and helped reduce income inequality.

Still, recent years have seen high-profile examples of billionaires leaving northern states for Florida or Texas, including Citadel founder Ken Griffin, who moved from Chicago to Florida in 2022, and billionaire investor Carl Icahn, who left New York for the Sunshine State in 2019. But for Icahn, who was 83 at the time, the move was “more about lifestyle than taxes,” Reuters reported.

The reality is, for individuals as well as for businesses, choosing a place to relocate involves many factors, including what the location has to offer, and what it costs.

“What makes New York attractive is we have an excellent labor market in terms of having great human capital; companies want to be here, and their employees like to be in New York City,” Ana Champeny, vice president for research at the Citizens Budget Commission, told Fortune.

Champeny added that high taxes play into the equation, as do other factors. Counting state and local taxes, New York City collects an average of $12,751 per capita, more than California’s $10,346. “We are well above the average, and we are significantly higher than high-tax states,” she said. “There’s always a risk that people are going to choose to relocate and businesses will choose to relocate, but increasing our taxes further would increase that risk.”

Back to the eighties?

While not all businesses can physically pick up and leave, New York’s real-estate sector fears the money will do exactly that if Mamdani pulls through on his promise to freeze rents—a factor that led the landlord lobby to pour millions into rival Andrew Cuomo’s primary campaign.

Kenny Burgos, CEO of the New York Housing Association, which represents landlords, argued further restrictions on rents would affect landlords’ ability to pay for repairs, making 40% of the city’s properties unaffordable and ultimately causing property owners to “walk away.”

“You will have vacant, deteriorated buildings, abandoned buildings, much like the Bronx had in the seventies and eighties,” he told Fortune. “You can’t pick them up and go anywhere else with them, so we are forced to contend with a potential administration who is threatening the very viability of these buildings.”

Indeed, landlords’ mass abandonment of properties during those decades forced the city and their tenants to take over much of the housing stock, leading to the creation of hundreds of thousands of low-cost apartments. (For perspective, New York’s current mayor struggled to get approval for a program to build 80,000 new units over 15 years).

Partnership for New York City CEO Kathryn Wylde, for her part, is encouraging members to focus on the facts, noting that “much of Mamdani’s agenda cannot be accomplished by a mayor, but are the province of the Governor and state legislature. A mayor cannot, for example, raise corporate or income taxes,” she said. Partnership members plan to meet with the candidate, to which he is “very open,” she added.

Progressive economist Paul Krugman is one of many who thinks the possibility of a crime-fueled doom loop accelerating New York’s deterioration is overstated. Compared to the crime-ridden eighties, “New York is one of the safest places in America, and probably as safe as it has ever been,” he said on Substack, recalling his own childhood growing up in the city’s suburbs when Times Square was full of sex shops and Columbia University deployed private security to protect faculty homes.

“New York’s problem now isn’t rampant crime or scary immigrants. It’s affordability,” he wrote. “And while we can and should debate the likely success of Mamdani’s proposals, affordability has been his main focus.”