New York's new tax on luxury second homes is moving forward despite a legal challenge and Trump's public fury, a win for Mayor Mamdani and bad news for absentee millionaires who use the city as a place to park wealth.

• Trump is threatening to find some federal way to block the tax, calling it a disaster that will drive rich residents to Florida and Texas.
• The tax targets expensive apartments and homes owned by people who rarely live in them, something New York lawmakers tried and failed to pass for over a decade against real estate lobbying.
• A lawsuit led by a former deputy mayor, Randy Mastro, only challenges the confusing rollout, not the tax itself, and a brief court pause was quickly reversed on appeal.
• The rollout has accidentally exposed wealthy people who claim to live in low-tax states like Florida but actually spend most of their time in New York, opening them to tax-fraud scrutiny.
• Mamdani's approval has climbed sharply, and threats from CEOs like Ken Griffin to flee to Miami keep stalling because their employees refuse to move.

Outlook: The tax looks set to survive the court fight, with the next battle shaping up over Mamdani's push to make Amazon responsible for its delivery drivers.