Central Park Tower, center, along Billionaire's Row in New York, US, on Friday, May 1, 2026. Michael Nagle | Bloomberg | Getty Images 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.…