Businessman Wilbur Ross and former casino magnate Steve Wynn are suing New York over Mayor Zohran Mamdani’s (D) pied-à-terre tax, which they claim is unconstitutional.

In a suit filed Monday in the Suffolk County branch of the New York Supreme Court, Ross — the U.S. commerce secretary in the first Trump Administration — and the founder of Wynn Resorts say the real estate tax violates both the state and U.S. constitutions because it targets nonresidents. The tax, a cornerstone of Mamdani’s 2025 mayoral campaign, was approved by the legislature in May and went into effect on July 1.

The tax is a revenue-generating effort focusing on second homes valued at more than $5 million and co-ops and condominiums estimated to be worth more than $1 million.

Ross and Wynn are both Florida residents, but they both own property in the Big Apple. Ross and his wife, Hilary Geary Ross, who’s also a plaintiff in the suit, own a house in Southampton, NY and a Manhattan co-op.

Wynn, who’s become a residential real estate mogul of sorts since leaving the casino industry in 2018, including flipping mansions in South Florida , may be even more motivated than his co-plaintiffs to fight the new real estate tax.

He purchased a Manhattan Ritz Carlton duplex for $70 million in 2012. To no avail, he tried to sell it for $90 million a decade later. That listing was pulled two years later, but the property is back on the market for $70 million and it’s estimated that Wynn’s annual carrying costs on the duplex are $565,000 – a figure that doesn’t include the pied-à-terre levy.

When Wynn’s New York property hit the market anew in July, some reports suggested that Mamdani’s tax could make the casino baron a motivated seller due to the fact that his personal politics don’t align with those of the mayor.

The tax doesn’t apply to New Yorkers living in pricy real estate in the city provided that those properties are their primary residences. That doesn’t sit well with Ross and Wynn who claim nonresidents are explicitly targeted by the tax.