The New York City Council on August 12 opened a probe into prediction markets Kalshi and Polymarket, plus crypto exchanges Coinbase and Gemini Titan, over alleged deceptive marketing practices. Council Speaker Julie Menin sent detailed questions to all four platforms examining potential social harms from their advertising. The inquiry targets how the platforms promote services within the city and could lead to local restrictions.

The city probe adds a New York attorney general suit as a fourth enforcement layer that Kalshi and Polymarket cannot block with federal registration alone. Menin's detailed questionnaire — covering revenue, operations, and ad content — becomes discovery ammunition for parallel state and federal cases. The four platforms must now budget for municipal lawyers on top of existing CFTC, congressional, and state court fights. Any ordinance the council passes could ban certain ads or mandate new disclosures, creating compliance zones that vary by city. For Coinbase and Gemini Titan, dragged in as crypto infrastructure, the probe links their retail user bases to prediction-market politics they had avoided. Chicago and Los Angeles are already watching the New York template.