The Pershing Square founder argues the mayor's rent freeze and city-run grocery stores would deepen the housing shortage, as Mamdani clears business leaders off the board of the Mayor's Fund.
Hedge fund manager Bill Ackman has become the loudest Wall Street voice against Mayor Zohran Mamdani's economic program, telling Fortune this week that New Yorkers should "watch what happens" if the mayor manages to enact it in full.
Ackman's core argument is that the city's affordability crunch is a policy failure rather than a market one. On his telling, decades of restrictions have made building in New York slow and expensive, and a rent freeze on the roughly one million stabilized apartments in the city would compound the damage rather than relieve it.
He pointed to the stock of rent-regulated units sitting vacant because owners say the cost of renovating them cannot be recouped under current rules — a figure he put at around 60,000. Freeze rents, he argued, and more landlords simply take units off the market rather than invest in them.
The mayor's plan for a network of city-backed grocery stores drew similar scorn. Ackman's position is that food prices are a supply and competition problem, and that a municipal retailer is an expensive way to avoid addressing either.
The exchange lands in the middle of an already frosty stretch between City Hall and the business establishment. This week Mamdani dismissed the entire advisory board of the Mayor's Fund to Advance New York City, clearing out executives tied to Blackstone, Citigroup, the Real Estate Board of New York and several large development firms.
The Mayor's Fund has historically leaned on exactly those relationships to raise private money for city programs — more than $100 million for the families of 9/11 rescue workers, and roughly $54.5 million during the pandemic. City Hall says the replacement board will seat people directly affected by city policy rather than the institutions that fund it.
Ackman also defended Ken Griffin, the Citadel founder who publicly clashed with Mamdani after the mayor filmed a video promoting his new pied-à-terre tax outside Griffin's Central Park South apartment. Griffin has since floated trimming his New York footprint, though Vornado Realty Trust confirmed this week that its $4.5 billion tower at 350 Park Ave., which will house Citadel's local offices, is proceeding as planned.
The wider point Ackman keeps returning to is a familiar one on Wall Street: a small number of very high earners cover a disproportionate share of the city's tax base, and policy that pushes them toward Florida or Texas costs the city more than it collects. Critics counter that the threat to leave has been made every cycle for forty years, and that the departures rarely match the rhetoric.
Mamdani's office has not responded publicly to Ackman's remarks.