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Prediction markets have stopped being a curiosity and become sports betting's most serious structural rival, and a single federal rule now in draft will decide how far they are allowed to go. Combined monthly trading volume on Kalshi and Polymarket rose from under 5 billion dollars in September 2025 to 24 billion dollars by April 2026, and sports trades, not politics, drove the surge.
That is not a parallel market. On Kalshi, sports-related event contracts have accounted for around 80% of volume since July 2024. The product sold to regulators as a tool for forecasting elections and economic data is, in practice, a sportsbook in everything but name, and the people running licensed sportsbooks know it.
Why prediction markets threaten the sportsbook model
A state-licensed sportsbook operates inside a cage. It pays a state licence fee and state tax on gross gaming revenue, geofences its product to legal states, and accepts the marketing and responsible-gambling rules a gambling licence carries. A federally regulated prediction market, supervised by the Commodity Futures Trading Commission rather than 38 separate state gambling regulators, sits outside most of that cage: it offers what looks like a wager on a game outcome, nationwide, under commodities law, without a state sports-betting licence and without state betting tax.
That regulatory arbitrage is the whole game. If a bettor in a state with a 51% tax rate, or with no legal sportsbook, can take the same economic position through an event contract, the licensed operator's cost advantage inverts, and the cage meant to protect incumbents makes them uncompetitive. This is the same fault line we traced in Kalshi's lawsuit against Illinois over a prediction-market betting tax, and the question underneath it has now reached Washington.
The CFTC's rule: what survives, what gets cut
On 10 June 2026, the CFTC proposed its first dedicated rule for prediction markets, best read as a partial blessing rather than a crackdown. According to ESPN's account of the proposal, the agency would permit most sports-related contracts tied to game outcomes and team performance, on the reasoning that they aid price discovery, while barring a defined set it considers contrary to the public interest: those on player injuries, refereeing decisions, in-game actions involving specific participants, youth sporting events, and war, assassinations or terrorism.
The comment period runs 45 days. CFTC chairman Michael Selig framed the rule as an attempt to build a durable, transparent framework for which contracts are allowed. Read commercially, the proposal validates the core of the prediction-market sports business, the moneyline-style "who wins" contract, while trimming the prop-style edges that most resembled a traditional sportsbook. That is closer to a green light than a roadblock.
A federalism fight headed for the Supreme Court
The harder battle is the constitutional question of who gets to regulate this at all. States argue these contracts are sports betting under their gambling authority; the CFTC and the platforms argue they are federally regulated derivatives state law cannot touch. That preemption clash is already in the courts, with Arizona, Minnesota and New York among the states in legal disputes, and CNBC has reported the CFTC moving against a broader group of states. Legal observers expect the question to reach the Supreme Court, possibly within a year.
The stakes for state treasuries are real. Sports-betting tax has become a meaningful budget line in dozens of states. If volume migrates to federally regulated venues that pay no state betting tax, that revenue does not move, it disappears, which is why states are fighting this as hard as the licensed operators are. A ruling affirming federal preemption would redraw the financial map of US betting, stripping states of a revenue stream they rely on and handing a structural cost advantage to whichever venues hold a CFTC registration.
Polymarket and Kalshi are not the same business
Treating prediction markets as a single bloc obscures an important split. On Kalshi, sports contracts drive around 80% of volume, making it a sports-trading venue with a forecasting veneer. Polymarket's mix is different, with sports closer to 39% of activity over the comparable period, leaving a larger share in politics, economics and culture. That matters: the CFTC's proposed carve-outs for injury, refereeing and youth contracts bite hardest on the platform most committed to sports, while a more diversified venue has other revenue to fall back on if the sports rules tighten.
It also shapes how the licensed industry should read the threat. The danger is not abstract event-contract trading, which has existed for years, but the specific, high-volume, sports-outcome contract that behaves like a moneyline bet and clears at scale. That is the product the CFTC's draft would largely permit, and the one competing for the same recreational bettor a sportsbook spends heavily to acquire.
The responsible-gambling gap
A quieter consequence sits underneath the tax and competition story. State sports-betting licences come bundled with consumer protections: deposit limits, self-exclusion registers, problem-gambling helplines, advertising restrictions and age verification. Federally regulated event contracts were not built around that framework, because they were conceived as financial instruments. As sports contracts pull in mainstream bettors, the question of who is responsible for player protection on a venue that looks like a sportsbook but is regulated like a commodities exchange becomes harder to wave away.
That gap is part of why state regulators are fighting so hard, and a credible basis for future federal conditions. If prediction markets keep absorbing sports-betting demand, expect responsible-gambling obligations to follow the volume, through CFTC rulemaking or the litigation now working its way upward. The Congressional Research Service has already flagged the unresolved questions for Congress, a sign the issue has moved beyond a niche.
The incumbents' dilemma
For the major sportsbook operators, the strategic bind is acute. Ignore prediction markets and risk watching price-sensitive handle leak to a cheaper, nationwide channel. Embrace them by acquiring or launching a CFTC-regulated venue, and risk cannibalising the state-licensed business that still generates the bulk of revenue while inviting scrutiny over what critics call unlicensed betting. This is no longer a two-horse race between Kalshi and Polymarket: on 16 June 2026, Novig won CFTC approval as a sports prediction market, CNBC reported, a sign the regulatory door is open wide enough for new entrants. Every quarter an incumbent waits, a competitor builds share.
The most probable outcome is hedging. Expect at least some established operators and exchanges to take positions in prediction markets, treating a federal registration as insurance against the erosion of their state-licensed economics. That fits the structural reading we set out in iGaming regulation in 2026 as a new operating system, where the licence, not the product, decides who can compete. The contract is almost identical to a bet, but the regulatory wrapper changes the entire economics.
Three likely outcomes
Three things are now likely. The CFTC will finalise a rule that legitimises core sports event contracts while pruning the most sportsbook-like props. The federalism question will grind toward the Supreme Court, and until it resolves, operators and states will keep litigating state by state. And the licensed industry will stop treating prediction markets as someone else's problem and start building or buying positions inside them.
The open question is whether prediction markets end up complementing the regulated sportsbook or hollowing it out. If the federal framework holds and state tax cannot reach event contracts, the pressure on the licensed model becomes structural, not cyclical, and the most valuable asset in US betting may turn out to be a CFTC registration rather than a state gaming licence.
Related on SparkNews: Kalshi Sues Illinois to Block Prediction Market Betting Tax | iGaming Regulation in 2026: The New Operating System