Zohran Mamdani’s primary win in New York City’s mayoral race and proposal to raise taxes on millionaires have touched off fears of a new wave of wealth flight from the city.... At the center of the economic concern is Mamdani’s so-called “millionaire tax.” He’s proposed an additional 2% tax on New Yorkers earning more than $1 million a year. Added to the city’s current top rate of 3.876%, the tax would bring the combined New York City and state tax to 16.776%, by far the highest in the country. The combined federal, state and city rate would be 53.776%. And...