Over a single weekend in October, trading across prediction market platforms passed $10 billion. TickerTracker put the figure at $10.4 billion, an 11% rise on the previous weekend, while DefiRate counted roughly $10.5 billion, according to Gambling Insider’s reporting. Here is prediction markets explained in one line: they are exchanges where you buy and sell contracts on whether a specific event happens, and the contract price is the market’s estimate of the probability. This piece puts them next to sportsbooks on the three things that actually matter: who sets the price, who regulates it, and why the public reacts so differently to the two.
First, the $10 billion figure is not what most people assume
That $10 billion was weekend notional trading volume across tracked platforms, not money staked on one election. Notional volume counts the face value of contracts changing hands, including the same position being bought and sold repeatedly by traders who never intend to hold to settlement. It is closer to a stock exchange’s turnover number than to a sportsbook’s handle on a single game.
The reporting also attributes much of the surge to combos, the multi-leg combination contracts that bundle several outcomes together. If that sounds familiar, it should. It is the prediction market’s answer to the parlay, and parlays are the highest-margin product traditional sportsbooks sell. Hold that thought, because it matters later.
So when you see “$10 billion bet on the election” in a headline, you are reading a real number wrapped in a wrong description. Kalshi alone surpassed $10 billion in volume over the two days of that weekend, about $10 billion of a $14 billion weekend total on that count. Enormous. Also not the same thing as $10 billion of election wagers.
What a prediction market actually is
A prediction market is a venue for trading binary contracts on real-world events, where each contract pays out a fixed amount if the stated outcome occurs and nothing if it does not. Kalshi and Polymarket are the two names driving most of the current volume. Kalshi runs as a regulated exchange for event contracts in the US; Polymarket built its following on crypto rails.
Mechanically, you are buying a yes or a no. A contract that settles at $1 trades somewhere between 1 cent and 99 cents, and that price is its implied probability. Yes at 62 cents means the market collectively prices the event at about a 62% chance. Because yes and no must sum to $1, the no side in that example sits at 38 cents. Buy 100 yes contracts at 62 cents and you have committed $62; if the event resolves yes, you receive $100.
The part that genuinely has no sportsbook equivalent is what happens in between. You can sell your contracts at any point before resolution at whatever the market will pay. If that 62-cent position drifts to 80 cents after a debate, a poll, a result, you can take 80 cents and walk. You are not waiting for an outcome; you are trading a probability. Sportsbooks offer cash-out, but the book decides the cash-out price. Here, the next trader does.
Who sets the price: the market or the house
This is the real dividing line, and it is a structural one rather than a moral one. A sportsbook sets its own prices and takes the other side of your bet. Its revenue comes from the margin baked into those prices. Two sides of a market priced at -110 each imply about 52.4% probability, summing to roughly 104.8%, which is where the book’s theoretical hold of around 4.5% lives. You never see a fee. You pay it in the odds.
A prediction market matches you against another trader through an order book. Yes at 62 and no at 38 add to exactly 100%, so there is no overround in the price itself. The exchange earns from trading fees and relies on market makers to keep the book tight. That does not make it free: you pay the bid-ask spread, you pay the fees, and in thin markets you pay a lot of both.
| Mechanic | Prediction market | Sportsbook |
|---|---|---|
| Who sets the price | Traders via an order book | The operator’s trading team and models |
| Your counterparty | Another user | The house |
| Built-in margin | No overround; fees and spread instead | Overround priced into the odds |
| Payout basis | Contract resolves to $1 or $0 | Stake multiplied by fixed odds at bet time |
| Exiting early | Sell into the order book at market price | Cash-out at a price the book quotes |
| Price after you commit | Keeps moving; your position is marked to it | Locked at the odds you accepted |
| Liquidity ceiling | However much the other side will trade | Operator’s own limits |
One honest consequence of the no-overround structure: on a liquid, heavily traded market, a prediction market can offer a better effective price than a sportsbook on the same question. On an illiquid one, the spread can be wider than any bookmaker’s vig. The averages that get quoted in the marketing conceal that gap entirely.
The regulatory split, and why it ended up in court
Prediction markets in the US are regulated by the Commodity Futures Trading Commission as derivatives venues, but that position is contested: a federal appeals court has ruled that states can regulate prediction markets as gambling, so the state-by-state gambling framework is not simply excluded. Sportsbooks need a licence from each state’s gaming commission, pay state gaming taxes, and follow that state’s rules on advertising, self-exclusion and player protection. An event contract exchange answers to a federal financial regulator under a framework built for commodities and derivatives, and, on that appeals court’s reading, potentially to state gambling regulators as well.
That is the entire fight in one sentence. States argue that selling a yes-or-no contract on who wins an election is gambling and therefore theirs to license or ban. The platforms argue these are federally regulated financial instruments and that state gambling law does not reach them. Kalshi and Polymarket have both cited the CFTC’s latest regulatory proposals in their court battles with states, which tells you how unsettled the position still is. Anyone writing with confidence about how this ends is guessing; check a current legal filing or the regulator’s own notices rather than a summary, because the picture is moving.
The pressure is showing up in commercial decisions too, not only courtrooms. Google has restricted prediction market advertising in Connecticut. Advertising restrictions tend to follow regulatory doubt, and platforms feel them long before a ruling lands.
Why the volume keeps climbing
Growth is being driven by a stack of factors rather than any single one: high-profile elections and political events that generate continuous news flow, media coverage that treats contract prices as forecasts, new platforms and new entrants competing for the same flow, and crossover from sports bettors who already understand odds. Macquarie, cited in the same reporting, sees considerably more room for the industry to grow this year.
The combos point deserves more weight than it usually gets. Multi-leg products boost volume because each leg counts toward the notional total, and they appeal to the same instinct that makes parlays dominate sportsbook revenue: small stake, large advertised return, worse expected value. A record set largely on combos is a record about product design as much as about public appetite for forecasting.
Innovation or gambling with a cleaner interface?
The popular verdict is that election betting markets are gambling. That verdict is correct, and the reason usually given for it is weak.
The weak reason is “you are risking money on an uncertain outcome, so it is gambling.” By that test, every insurance policy and every commodity hedge is gambling, and the people who use event contracts to hedge genuine exposure, a farmer on weather, a business on a policy decision, have a fair answer to it.
The stronger reason is behavioural and structural. The overwhelming majority of retail users on these platforms are not hedging anything. They hold a directional position on an outcome they cannot influence, on an app built around the same loop as a betting app, increasingly through parlay-shaped products. Call it a derivative if the statute says so. It functions, for that user, exactly like a bet, and the consumer protections attached to it come from a financial regulator that was never designed to think about problem gambling.
Public opinion has arrived at the same place without the technical argument. A Reuters/Ipsos poll cited in the same reporting found widespread opposition to betting on elections, military actions and government decisions. Critics raise election integrity, the optics of a financial incentive attached to a vote, and exposure for vulnerable users. Proponents point to forecasting value, price discovery and the fact that these markets often read the room better than polls.
If you trade these markets, treat the money as money you can lose. Set a deposit and loss limit before you open a position, keep a session clock, and if the political news cycle is driving your clicks, step back. The tools you would use at a licensed sportsbook are not uniformly available on a derivatives exchange, which puts more of the discipline on you.
What changes if this sticks
The competitive threat to sportsbooks is not better odds. It is scope. An exchange with federal registration can quote markets a state-licensed book cannot touch, in states where that book has no licence at all, and it can do it on politics, economics, awards and weather alongside sport. Expect sportsbooks to push for parity rather than to compete on price, and expect that fight to be fought in legislatures and courts rather than on promotions.
What stays genuinely open is which regulator ends up in charge of the retail user, and whether the rules that follow look like financial rules or gambling rules. That distinction decides advertising limits, age verification, self-exclusion, tax treatment and who you complain to when something goes wrong. Before you use either product, the question worth answering is not which has the better price on a given weekend. It is which one, when the market closes against you, you actually have recourse under.