High-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.