The Mamdani administration has grossly underestimated how much it will owe the Metropolitan Transportation Authority in the mayor’s first budget, even as he pursues a campaign pledge to make city buses free, a budget watchdog said. New York City will need to pay about $621 million more than the Mamdani administration has penciled in for MTA subsidies in fiscal year 2027, according to the New York City Comptroller’s office, which called out “contributions to MTA” as one of the clearest examples