‘Socialism is a disaster’: Bill Ackman says Zohran Mamdani’s bad left-wing housing policy is worsening New York’s affordability crisis

In a wide-ranging interview with Fortune Editor-in-Chief Alyson Shontell for the Fortune 500 Titans and Disruptors of Industry podcast series, the Pershing Square CEO argued that New York’s affordability crisis is a policy failure, not a market one — and that Mayor Zohran Mamdani’s rent-freeze agenda is actively making things worse.

“Let’s use New York City as a microcosm, starting with the cost of housing,” Ackman told Fortune. “It’s so high because left-wing mayors have made it very difficult for developers to build here, and Mamdani, by freezing rents, is just going to make the problem worse.”

The comments land months after Mamdani, a self-described democratic socialist, took office and delivered on a signature campaign promise: in June, New York City’s Rent Guidelines Board voted 7-1 to freeze rents on one- and two-year leases for nearly one million rent-stabilized apartments — the first such freeze on two-year leases in the city’s history. Mamdani called the vote “a historic victory for New York City tenants.” Ackman sees it differently.

A market split down the middle

Ackman’s core argument is structural: New York’s rent-stabilization system, he says, has effectively split the housing market in two — and landlords are compensating for frozen income on one side by squeezing tenants on the other.

“In many New York City buildings, roughly half the tenants are in rent-stabilized apartments with frozen rent, and the other half are at market rate,” Ackman said. “So landlords raise rents on the free-market half to generate enough cash flow to cover their interest expense. That’s bad policy contributing to the affordability problem.”

He also pointed to a specific consequence of rent regulation that he says has quietly removed housing stock from the market altogether: landlords pulling units offline because they can’t recover renovation costs under current rules. “About 60,000 units are off the market because renovation costs can’t be recovered under rent regulations,” he said. As of April 2026, the state reported over 57,000 vacant rent-stabilized apartments.

Advocacy groups and city data have long tracked a large inventory of vacant rent-stabilized units, though the underlying causes are contested. Tenant groups and some housing researchers argue deregulation, not stabilization, has done more long-term damage to affordability, noting more than 300,000 units were deregulated between 1994 and 2019. A Moody’s analysis cited by tenant advocates found a five-year rent freeze would put only about 6% of multifamily loans citywide at risk of default by 2030.

Energy costs and the build-more argument

Ackman extended the same critique to New York’s energy costs, which he also attributed to policy choices rather than market forces. “Why are energy costs so high in New York State? Because we’ve shut down nuclear power, it takes 15 years to get a pipeline approved, and we’ve banned fracking — so we’re importing natural gas from Pennsylvania. That’s just bad policy, and we can fix a lot of it with better policy.”

Ackman may have been referring to the Constitution Pipeline, which filed for approval in 2012 only to see New York’s DEC deny the required water-quality permit in 2016, the Second Circuit upheld that denial in 2017, and after years in regulatory limbo the company withdrew its application entirely in November 2025 — roughly 13 years after the process began, with the pipeline never built.

On real-estate policy, he held up two contrasting examples. Florida, he said, is “an incredibly well-managed state that recently voted to eliminate real estate taxes, purely through good policy.” That’s a bit on exaggeration, although essentially true — the Florida state legislature has placed a property-tax-reduction measure on the November 2026 ballot and it still requires 60% voter approval; it would phase in a larger homestead exemption rather than eliminate property taxes outright.

Austin, Ackman noted, has seen rents fall “significantly because it’s easy to build” — a supply-side argument echoed by researchers who have called New York’s housing shortage “self-inflicted and solvable” through zoning and permitting reform. That’s not an exaggeration, as Austin rents have been falling for several years.

Ackman takes a clear lesson from these examples: “If you make it hard to build where people want to live, and you don’t let landlords recover renovation costs, they’ll pull units off the market.”

The wealth he wants to keep — and the tax he doesn’t

Ackman’s housing critique is inseparable from his broader argument about who should be welcomed in the city. He pointed approvingly to billionaire Ken Griffin investing in the city, and paying roughly $250 million for an apartment (the subject of a controversial Mamdani TikTok video). “That purchase makes a building economically viable, which creates construction jobs and brings in wealthy residents who pay taxes,” Ackman argued.

“You want the top earners — who are a small share of the population — paying a large share of taxes,” he said, estimating that the top 10% of earners generate 70% of tax revenue. “That’s not particularly unfair. But you don’t want to discourage people like Elon Musk from locating their businesses here.”

He drew a direct line from that principle to his opposition to Mamdani’s other major revenue idea, a “pied-à-terre” tax on second homes owned by non-residents, and to California’s wealth tax, warning that such levies rarely stay contained. “They say it’s ‘one time,’ but it’s never one time,” Ackman said. “Income taxes started out small too and only applied to a few people.” Recent Fortune reporting has separately noted that Mamdani’s pied-à-terre tax push has run into complications tied to the city’s large population of unregistered “ghost cars” and absentee owners, underscoring how difficult such levies are to enforce in practice.

When addressing socialism, Ackman didn’t hedge: “The answer isn’t socialism — socialism is a disaster.” Then he issued a warning: “Watch what happens to New York City if Mamdani succeeds in implementing these plans.” Ackman’s public posture toward Mamdani dates back to the mayoral primary, when Ackman pledged to fund a centrist alternative and called Mamdani’s platform “disastrous for NYC.”

A billionaire’s case for capitalism

The housing critique is part of a larger argument Ackman made throughout the interview: that capitalism, not government redistribution or philanthropy, is the most efficient tool for solving affordability and inequality. Ackman has long argued that a person’s significance in life is ultimately measured by how positively they affect the largest number of people.

He also connected the debate to a broader worry about the “wealth effect” of equities investment: nearly half of Americans aren’t participating in stock-market gains, and Ackman traces this dynamic back to support for candidates like Mamdani. Rather than argue America is too reliant on stock-market wealth, Ackman took the opposite view: “Wages can’t compound as quickly as stocks, so everyone needs to participate in the stock market in order to believe in capitalism,” Ackman said — the rationale he’s given for pitching the Trump administration on what became the “Trump savings plan,” a 401(k)-style account with a government match aimed at workers without employer retirement plans.

Whether Ackman’s diagnosis holds up against the city’s own housing data remains contested, but as Mamdani’s rent freeze takes effect, the fight over who’s to blame for New York’s affordability squeeze is only getting louder. Ackman, with 2.7 million followers and a direct line to the White House, isn’t planning to go quiet.

For this story, Fortune journalists used generative AI as a research tool. An editor verified the accuracy of the information before publishing.

Watch Fortune’s full interview with Bill Ackman, here.