A trio of Big Apple homeowners have filed suit to delay the state’s controversial new tax on luxury second homes — claiming Mayor Zohran Mamdani’s administration bungled the rollout.

The group of disgruntled owners charge City Hall is unfairly burdening them to prove they are full-time New Yorkers and, as such, not subject to the pied-à-terre tax, according to the suit filed Friday in Staten Island Supreme Court.

The city Department of Finance “has arbitrarily and capriciously foisted onto New York City residents the burden of proving they are not subject to the Surcharge,” the filing states.

New York City Mayor Zohran Mamdani initiated a “pied-à-terre tax” targeting luxury, non-primary residence properties worth over $5 million in NYC earlier this year. Instagram/@nycmayor

It specifically calls out the DOF’s move to publish a tax roll of nearly 1 million properties that may be subject to the new surcharge and the 17,000 notices it mailed to homeowners warning them they would be hit with five-figure bills unless they filed for an exemption.

The city ignored its statutory obligation to do its homework first “to diligently assess and determine, using the vast resources at its disposal, the properties that are actually subject to the Surcharge,” the suit charges.

While the suit doesn’t challenge the law itself, it demands that a judge declare the city’s actions illegal and immediately scrub the 900,000-name list from the DOF website, claiming its publication “set off a panic among New York City homeowners.” 

On top of that, the city has since “furiously backpedaled” to later state that the list was “meaningless,” according to the suit.

That list “should never have been posted in the first place,” the lawsuit states, and “has caused mass confusion as a result, and should therefore be immediately removed from DOF’s website.”

It also requests an emergency injunction to void the 17,000 mailed notices and relieve homeowners from having to respond. The Mamdani administration last weekend extended the deadline to file for an exemption to Sept. 18, from the end of August.

Three NYC homeowners are now suing to delay the new pied-à-terre tax, claiming Mayor Mamdani bungled the rollout to nearly one million properties. Christopher Sadowski for NY Post

The plaintiffs are represented by attorney Randy Mastro, who served as first deputy mayor under Mamdani’s predecessor Eric Adams.

Two of the suing homeowners are the wife and father of City Councilman Frank Morano, both Staten Island residents; the third is a Chelsea resident. All claim they either received a notice letter referring to their longtime primary residence, or that the home was listed on the published tax roll.

Start your day with all you need to know

Morning Report delivers the latest news, videos, photos and more.

Thanks for signing up!

The law, approved by the state Legislature and Gov. Kathy Hochul, is meant to apply to one-to-3 family homes worth at least $5 million and co-ops and condominiums valued at $1 million or more — that are unoccupied, non-primary residences.

Ahead of the notices being sent out, Mamdani last month released a taunting video telling owners of second-homes worth more than $5 million to “check your mailbox.” 

Ahead of the notices being sent out, Mamdani last month released a taunting video telling owners of second-homes worth more than $5 million to “check your mailbox.”  X/SaraEisen

But the warning letters sent out by DOF roughly tripled the number of homes that would be subject to the law, according to the department’s former commissioner, Martha Stark.

According to the city’s own published data, fewer than 3% of the 960,000 properties on the tax roll — roughly 24,000 — “meet the statutory value threshold” of $5 million for 1-3 family homes and $1 million for co-ops and condos, said Stark, in an expert affirmation filed alongside the suit.

Stark, who has also been involved in a decade-long lawsuit over the city’s property tax system writ large, claimed that the 17,000 letters were “strikingly over inclusive” and estimated that the true number of subject properties was between 5,000-6,000.

The law is meant to apply to one-to-3 family homes worth at least $5 million and co-ops and condominiums valued at $1 million or more — that are unoccupied, non-primary residences. Bloomberg via Getty Images

State law permitted the city to gain access to a far larger set of records — like state income-tax data — to aid in assessing the properties subject to the new levy, “yet it published a list untethered to that information,” Stark claimed about the DOF.

Mastro himself said he received one of the notorious notices at his Upper East Side home, a massive six-bedroom townhouse he purchased for $14.3 million in 2016 and has lived in since.

“Given my recent employment by the city — in a high level role requiring that I reside in New York City no less,” Mastro wrote in a court filing, “it is inconceivable that the City’s Department of Finance did not have records available to it demonstrating that my primary residence is at the property to which it sent me this notice.”

City Hall did not immediately comment on the suit, which names the city, Mamdani in his official role as mayor, the DOF and its commissioner, Richard Lee.