Zohran Mamdani has said billionaires shouldn't exist . Some of them are spending big in an effort to stop him from becoming mayor of New York City. After failing to defeat the Democratic socialist state assemblyman's campaign during the June primary, several big-name billionaires have continued to pour money into outside groups aimed at stopping Mamdani and boosting his main rival, former Gov. Andrew Cuomo. Those groups include Fix the City, a pro-Cuomo group that's raised $7.3 million since