A coalition of some of New York City’s wealthiest financiers has launched an independent expenditure committee, “New Yorkers for a Better Future Mayor 25,” to counter Democratic mayoral nominee Zohran Mamdani, according to people involved in the effort. The group plans to raise about $20 million over the coming months for television, digital and direct-mail campaigns aimed at weakening the progressive candidate before November’s general election. The push marks the most organized attempt yet by business-aligned donors and establishment Democrats to halt Mamdani’s momentum after his surprise victory in last month’s primary. Hedge-fund manager Bill Ackman has separately urged a centrist challenger to enter the race, saying significant capital could be marshaled “overnight” to defeat the 33-year-old democratic socialist, who has built a large volunteer network and currently leads early betting markets. New York City’s electorate is heavily Democratic, making the party’s nominee the presumptive front-runner, but donors involved in the new committee argue Mamdani’s housing and tax proposals would hurt the city’s economy. The emerging big-money campaign sets up a high-stakes clash between well-funded outside spending and a grassroots operation in the final four months before Election Day.