New York City Council has opened a formal investigation into Kalshi, Polymarket, Coinbase and Gemini Titan over how the prediction market platforms market themselves to city residents. Council Speaker Julie Menin announced the inquiry on Wednesday, describing some of the marketing tactics as predatory and potentially false or deceptive.

Letters went out to all four companies this week. Each contains more than 60 questions covering New York revenue figures, local user counts and the specific mechanics behind how the platforms recruit new traders through ads, app store promotion and sponsorship deals.

Council members say they are especially concerned about outreach that reaches young people and users who show signs of compulsive betting behavior. The letters ask each company to spell out what safeguards exist, if any, to screen vulnerable users before they start trading contracts tied to elections, sports outcomes and economic data releases.

Prediction markets have expanded quickly since federal regulators cleared a path for CFTC regulated exchanges to offer event contracts nationwide, sidestepping the state by state licensing that governs traditional sports betting. Kalshi and Polymarket have both leaned hard into advertising, celebrity partnerships and aggressive app store campaigns to pull bettors away from offshore sportsbooks and into their own products.

That growth is exactly what has caught the council’s attention. Menin’s office is weighing whether to extend the same marketing rules that already bind casinos and licensed sportsbooks in New York, a move that could bring limits on how these platforms target minors, restrictions on sign up bonuses, or mandatory addiction warning language in ads.

The council plans to hold a public hearing once the four companies respond. Each has 14 days to answer in full. Legislation is also on the table, including measures that could authorize fines, public education campaigns or new health focused disclosure requirements for prediction market advertising in the city.

None of the four companies had issued a detailed public response to the specific allegations as of Thursday. Kalshi and Polymarket have both said in the past that their platforms operate under federal oversight and are open to regulatory dialogue, though neither has directly addressed Menin’s marketing complaints this week.

What happens next depends largely on how the companies respond over the coming two weeks. A public hearing would put executives from all four platforms in front of council members directly, the first time New York lawmakers would question the industry face to face over its advertising practices.