Baltimore has filed a lawsuit targeting Kalshi and Polymarket, two of the best-known prediction market platforms operating in the United States. The Block reported the filing on August 13, noting that the city also named Coinbase, Robinhood and Webull as parties. Those three firms have each offered customers ways to access event-contract trading tied to Kalshi's markets.
Prediction markets let users trade contracts based on the outcome of real-world events. These range from elections to economic data releases to sports results. Kalshi operates under a federal license from the Commodity Futures Trading Commission, which classifies its offerings as derivatives. Polymarket, by contrast, has largely operated offshore and outside direct CFTC oversight, drawing scrutiny of its own.
The involvement of Coinbase, Robinhood and Webull reflects how deeply these platforms have become woven into mainstream retail trading. Each of these brokerages has built products or partnerships that route customer orders into event-contract markets. That integration has made them visible targets whenever regulators or municipalities challenge the underlying markets themselves.
Baltimore's suit follows a broader trend of state and local pushback against prediction markets. Several states have argued that these products function as unregulated gambling rather than legitimate financial instruments. Kalshi has fought some of these challenges in federal court, arguing that its CFTC registration preempts state gambling laws. Courts have not uniformly resolved that tension.
The specifics of Baltimore's legal theory were not detailed in initial reporting. It remains unclear whether the city is pursuing consumer protection claims, gambling law violations, or another legal basis. The inclusion of brokerages alongside the platforms themselves suggests the city may be arguing that facilitating access carries its own liability, separate from operating the markets directly.
This case adds another jurisdiction to a patchwork of legal fights already underway around the country. Kalshi in particular has faced actions from state gaming regulators in places such as Nevada and New Jersey. Those disputes have centered on whether federally regulated derivatives can override state-level gambling restrictions. Baltimore's filing suggests that tension is now extending to municipal governments as well.
Market Impact
For Kalshi and Polymarket, an additional lawsuit adds legal cost and uncertainty regardless of its eventual outcome. Platforms already navigating multiple state challenges may face further scrutiny of their compliance posture in other jurisdictions watching this case closely.
For Coinbase, Robinhood and Webull, being named alongside the platforms could pressure their product decisions around event-contract access. Brokerages that have leaned into prediction markets as a growth area may need to weigh legal exposure against customer demand. Investors in these publicly traded companies may watch for disclosures addressing the litigation.
Baltimore's lawsuit underscores how unsettled the legal status of prediction markets remains in the United States. With brokerages now drawn into the dispute, the case could shape how widely these markets can be distributed to retail traders going forward.
Frequently Asked Questions
What are Kalshi and Polymarket?
They are prediction market platforms that let users trade contracts based on the outcome of events, such as elections or economic data. Kalshi operates under CFTC registration in the United States, while Polymarket has largely operated outside direct U.S. oversight.
Why are Coinbase, Robinhood and Webull named in the lawsuit?
According to The Block, these brokerages are included because they have offered customers access to event-contract trading linked to Kalshi's markets. Their role as distribution channels appears to be part of the city's legal claims.
Is this the first legal challenge Kalshi has faced from a government body?
No. Kalshi has previously faced actions from state gaming regulators, including in Nevada and New Jersey, over whether its products constitute unlawful gambling under state law.
What outcome could this lawsuit have for prediction markets broadly?
The case could influence how courts and regulators view the legality of prediction markets and the liability of firms that provide access to them. Details of Baltimore's specific legal claims were not fully outlined in initial reporting.