A New York judge halted Mayor Zohran Mamdani's new property tax surcharge and ordered the city to pull down a list exposing the personal information of more than 900,000 homeowners, a ruling the mayor's office vowed to fight on appeal.

Staten Island Supreme Court Justice Wayne Ozzi, a Democrat, issued a temporary restraining order Monday that bars the Mamdani administration from enforcing its pied-à-terre surcharge while a lawsuit challenging the rollout moves forward. The order blocks the city from imposing or collecting the tax, sending further notices, or acting on letters already mailed to roughly 17,000 property owners. It also forces City Hall to take down a publicly available database that listed names, addresses, and property values of the affected homeowners, a database the court found caused irreparable harm.

The ruling amounts to a direct judicial check on one of Mamdani's signature revenue policies. The surcharge, developed in coordination with Gov. Kathy Hochul, targets properties deemed non-primary residences. Houses valued above $5 million face rates between 0.8% and 1.3%. Condominiums and co-ops worth more than $1 million face steeper rates, ranging from 4% to 6.5%. Advocates of the tax project it will generate $500 million in annual revenue, money Mamdani has described as "critical revenue to fund our parks, schools and libraries."

Homeowners sued after city skipped legally required steps

The lawsuit was filed last week by three homeowners, one of whom described herself as a Mamdani supporter, after the city's rollout generated widespread confusion. Their attorney, Randy Mastro, a former first deputy mayor under Mamdani's predecessor Eric Adams, argued that officials failed to conduct the individualized determination required by state tax law before mailing notices. Instead, the city published a sprawling list of over 960,000 properties and shifted the burden onto homeowners to prove they should not be taxed.

Many of the flagged properties appeared to fall well outside the surcharge's intended scope, yet their owners received notices anyway. As the New York Post reported, the lawsuit contended the rollout "caused mass confusion" by ignoring state data already available to properly assess which properties were eligible.

Judge Ozzi agreed. Fox News reported that Ozzi found the city had caused irreparable harm and that the plaintiffs were likely to succeed on the merits, a significant finding at this early stage. The restraining order holds until at least an August 31 hearing.

Mastro did not hold back about the administration's handling of the process.

"The city screwed this up... got it wrong... stop the train and make them do it over."

He added in a separate statement that the ruling "vindicated the rights of hundreds of thousands of New York City homeowners who were subjected to a process they never should have been a part of in the first place."

Mamdani vows to appeal while Hochul distances herself

The mayor's office pushed back immediately. Mamdani spokesman Matt Rauschenbach said the administration disagrees with the ruling. Breitbart reported his statement in full:

"We disagree with today's ruling, but we are confident in both the pied-à-terre surcharge and the City's ability to implement it fairly and effectively."

In an earlier press release, Mamdani struck a more combative tone:

"We will diligently implement this law and ensure that we collect what working New Yorkers, and this city, deserve."

Gov. Hochul, who worked with Mamdani to bring the surcharge into effect, appeared eager to put distance between herself and the fallout. "We're not responsible for the rollout," she told reporters. "This is something that we talked to the city about in advance. It's up to their city tax department." That statement left the mayor holding the bag for an implementation the governor helped set in motion.

The episode fits a pattern for Mamdani's young administration. The city's first socialist mayor has already clashed with the courts on other fronts, including his refusal to accept a Supreme Court ruling on deportation protections for Haitian and Syrian nationals.

Nearly a million homeowners caught in a dragnet meant for the wealthy

The core problem with the rollout is one of scale and sloppiness. The surcharge was pitched as a tax on the wealthy, owners of luxury pieds-à-terre who park money in high-end New York real estate without making it their primary home. The projected $500 million in annual revenue was supposed to flow to parks, schools, and libraries.

But the city cast a net that swept up more than 960,000 properties. Homeowners who had lived in their residences for years suddenly found their names, addresses, and property values published on a city website, with letters demanding they prove they were not subject to the new tax. The administration did not first verify which properties actually qualified. It just published the list and told people to sort it out themselves.

That approach, the plaintiffs argued, violated state tax law, which requires the city to make an individualized determination before sending notices. Judge Ozzi's order bars the city from sending any further notices without completing that legally required step first.

Republican members of the New York City Council warned last week that the surcharge "will decrease revenue and further drive away New York's highest spenders who help build our city's economy." Councilwoman Inna Vernikov went further in a post on X:

"This is Marxism in practice: consistently promising to better the lives of the middle class by punishing the 'wealthy.'"

Critics like Vernikov have a point that the policy's defenders have yet to answer: if the tax was designed to target a narrow class of wealthy absentee owners, why did the city's own rollout flag nearly a million properties and expose the personal data of homeowners who plainly did not qualify?

That question matters beyond this single policy. As one recent analysis noted, Democrats spent years warning about the dangers of executive overreach, then watched their own mayor repeatedly test the boundaries of legal authority.

Ozzi's ruling puts the burden back where it belongs

The restraining order does not kill the pied-à-terre surcharge. The underlying law remains on the books, and the Mamdani administration has made clear it intends to appeal. The next hearing is set for August 31, and the legal battle over the surcharge's implementation could stretch well beyond that date.

But the order does something the city refused to do on its own: it forces officials to follow the process the law requires before demanding money from homeowners. No more mass mailings without individualized review. No more public databases exposing the personal information of hundreds of thousands of people who may owe nothing.

Mamdani has also pledged to defy court rulings on other matters, raising the question of whether this administration views judicial orders as binding obligations or mere suggestions. The Washington Examiner reported that the mayor's office plans to appeal, and Mamdani's public statements suggest he views the surcharge as non-negotiable.

For the roughly 960,000 homeowners whose information was dumped onto a city website without their consent, the appeal is cold comfort. The damage from the list's publication, names, addresses, property values, all searchable, cannot be fully undone by a court order to take it down.

A policy sold as making the rich pay their fair share ended up exposing the personal data of nearly a million ordinary homeowners and demanding they prove their innocence. That is not tax policy. That is government working backward, and a judge, even one from the mayor's own party, told him to stop.