Central Park Tower, center, along Billionaire’s Row in New York, US, on Friday, May 1, 2026. Michael Nagle | Bloomberg | Getty ImagesHigh-end real estate sales in Manhattan increased in the past month, according to new data, despite New York Mayor Zohran Mamdani’s proposed pied-à-terre tax that brokers warn could cause a wealth flight.There were 133 contracts signed for apartments priced at $4 million or more between April 14 and May 10, according to Olshan Realty. That compares with 130 during the same period last year. The total dollar volume increased by 10% to $1.12 billion, Olshan said.Sales at the very high end remain especially strong, with contracts signed for apartments priced at $10 million or more surging by 80% to 34 contracts. The strength comes as real estate brokers and business leaders warn that a new second-home tax will chase away the New York wealthy and their valuable spending.”The last four weeks demonstrates that an impending pied-à-terre tax has had no effect on the luxury market in Manhattan,” said Donna Olshan, president of Olshan Realty. The market could turn once the tax is imposed, of course. Yet the surge comes as the proposed pied-à-terre tax makes its way through the New York legislature and sparks a highly public and bitter battle over taxing the wealthy in New York. The tax, first proposed by Mamdani and New York Gov. Kathy Hochul on April 15, would be an annual levy on non-primary real estate in New York valued at $5 million or more. Mamdani said the tax will raise $500 million in annual revenue and force the part-time New Yorkers to “pay their fair share.”Real estate brokers have lobbied to halt the tax in Albany, saying it will hurt the market and cost jobs and tax revenue. Second-home owners in New York already pay property taxes but don’t typically use many public services like schools or public transportation. Corcoran Group President and CEO Pamela Liebman told The Real Deal last week that Corcoran “has so many deals that have been put on pause, particularly at the $30 million, $40 million level, that are just wait and see.”The battle over the tax also became highly personal after Mamdani announced his proposal with a social media v …