Baltimore sues Kalshi and Polymarket, roping Coinbase, Robinhood and Webull into the fight

Baltimore is picking a fight that should make every founder in the decentralized finance space sit up and pay attention. Mayor Brandon Scott and the City Council have officially filed suit against the big names in prediction markets—Kalshi and Polymarket—and they aren't stopping there. They’ve managed to pull Coinbase, Robinhood, and Webull into the mix too. The core of the complaint? They’re calling these platforms illegal gambling dens masquerading as financial innovation.

The Prediction Market Identity Crisis

For a long time, the pitch for prediction markets has been simple: these aren't bets, they’re data. Proponents argue that by letting people put money on the line, we get better signals about future events than any poll or pundit could provide. If you want to know who will win the election or if the Fed will cut rates, look at the liquidity on Polymarket. It’s the wisdom of the crowd, backed by cold, hard cash.

Baltimore sees it differently. The city's legal team is framing this as a public nuisance and a violation of consumer protection laws. By their logic, if you’re placing a wager on an event you can't control, you’re gambling. And in their eyes, if you haven’t followed the specific, often grueling, state-by-state licensing required for sportsbooks, you’re breaking the law. They are specifically targeting the way these platforms have allowed users to speculate on things like the outcome of the Super Bowl or political races, claiming it circumvents the safeguards meant to protect residents from the harms of unregulated betting.

Why the Brokers Are Getting Dragged In

The most interesting part of this lawsuit isn't actually the attack on Kalshi or Polymarket. We’ve seen regulators go after the primary platforms before. What’s new—and frankly, more dangerous for the ecosystem—is the decision to rope in the on-ramps and trading interfaces like Coinbase and Robinhood.

Baltimore is essentially arguing that these platforms are facilitators. If Coinbase provides the infrastructure that allows a user to move funds into a prediction market, or if Robinhood integrates these tools into their user interface, the city believes they share the liability. This is a classic secondary liability play. It’s a message to the entire industry: if you help people access these markets, you’re just as guilty as the people running them.

For builders, this is a massive red flag. We’ve spent years trying to figure out where the line is between a decentralized protocol and a centralized gateway. If this lawsuit gains traction, that line becomes a blurred mess. It suggests that even if your software is neutral, the act of connecting a user to a specific "illegal" service makes you a target.

The Founder’s Reality Check

I’ve talked to dozens of founders who think that being "decentralized" or using smart contracts is a legal shield. It’s not. Baltimore isn't suing the code; they’re suing the entities that make the code accessible to humans with bank accounts. Polymarket has already had its run-ins with the CFTC, paying fines and agreeing to block U.S. users. But as anyone with a VPN knows, those blocks are often more like speed bumps than walls.

The city is capitalizing on this. They are pointing to the fact that these markets are still widely accessible to their residents despite supposed restrictions. They are arguing that the companies aren't doing enough to stop it, or worse, that they are quietly profiting from the loophole. From a founder's perspective, this means your compliance budget might soon need to be as big as your engineering budget. You can't just build a cool tool and walk away; you have to police how it’s used, or at least be prepared to prove in court that you tried.

The Impact on Innovation

If every city in America starts suing every platform that lists a prediction market token or provides a wallet connection, the industry will stall. Innovation requires a certain level of permissionless experimentation. But when you move into the territory of "event contracts"—which is just a fancy way of saying betting on the future—you are stepping into a regulated minefield that has existed since long before Bitcoin was a whitepaper.

The irony is that prediction markets are actually one of the most useful applications of blockchain technology. They provide transparent, tamper-proof ledgers for outcomes. They eliminate the "house" in many cases, offering better odds to the user. But regulators and city officials don't care about the tech stack. They care about the social impact. They see the rise in gambling addiction and the loss of local tax revenue, and they want someone to pay.

• Liability is expanding: The inclusion of Coinbase and Robinhood shows that regulators are going after the entire supply chain of a transaction.
• State vs. Federal: Even if a platform gets a green light from a federal agency like the CFTC, local municipalities can still cause legal nightmares using state-level consumer laws.
• The "Data" Defense: The argument that these are purely information tools is being tested, and it’s not looking strong in the eyes of local prosecutors.

What This Means for You

If you’re building in the prediction space or the on-ramp space, you need to stop assuming that the "it's just code" defense will save you. The legal system moves slowly, but it moves with a lot of weight. Baltimore’s lawsuit is a template. If they win, or even if they get a lucrative settlement, expect dozens of other cities to follow suit. It becomes a new revenue stream for local governments.

The goal here isn't just to stop the betting; it's to force these massive tech and crypto companies to integrate with the existing regulatory framework of the legacy gambling industry.

We are entering a phase where the "move fast and break things" era of crypto is hitting a brick wall of local governance. For builders, the takeaway is clear: focus on robust geofencing, actual KYC that works, and maybe stop calling your platform a "prediction market" if you're letting people bet on the Knicks game.

This isn't just a legal spat in Maryland. It's a fundamental challenge to the idea that crypto-native markets can bypass the rules of the physical world. Baltimore just fired a shot across the bow, and the target isn't just a few apps—it's the entire infrastructure of how we trade on the future.

Read the original at The Block →