Bill Ackman has a diagnosis for why it’s so expensive to live in New York City, and it isn’t capitalism — it’s City Hall. “Let’s use New York City as a microcosm, starting with the cost of housing,” Ackman told Fortune. Mamdani called the vote “a historic victory for New York City tenants.” “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. Then he issued a warning: “Watch what happens to New York City if Mamdani succeeds in implementing these plans.”