Prediction markets vs betting exchanges: what's the difference?

A prediction market and a betting exchange are close cousins. Both are peer-to-peer markets where the price reflects a crowd’s estimate of how likely something is, and both let you trade your position before the event finishes rather than just bet and wait. The main differences are the contract format, the regulator, and what you can legally access from the UK.

Both are real-money gambling. Both carry real financial risk. This article is general information, not financial or legal advice, and it is not tipping.

What a prediction market is

A prediction market lets you buy and sell contracts tied to a future event, usually a binary yes/no question. Think “Will X happen by this date?” The contract is priced somewhere between 0 and 1. On dollar-denominated platforms that means roughly $0 to $1 per share.

Say a “yes” contract trades at $0.60. If the event resolves yes, each share settles at $1, so you gain $0.40. If it resolves no, the share settles at $0 and you lose your $0.60. You do not have to hold to the finish, though. If the price moves up to $0.75 before resolution, you can sell and take the difference. If it drops, you can sell to cut the loss.

That price is the important part. A “yes” at $0.60 is the market saying, in effect, that it puts the chance at about 60 per cent. The number is an implied probability, set by people buying and selling, not a forecast handed down by a bookmaker.

Two names come up most often. Kalshi and Polymarket are both regulated in the United States under the CFTC, the commodities regulator. Polymarket is crypto-native, settled in stablecoins, and it is not legal to use from the UK. We cover that point in more detail in is Polymarket legal in the UK.

What a betting exchange is

A betting exchange does a similar job with a different mechanism. Instead of buying a yes/no share, you back or lay an outcome at decimal odds, and you do it against other users rather than against a bookmaker. There is no house setting a margin on the outcome. The exchange simply matches people who disagree and takes a commission on winnings.

To back is to bet that something will happen. To lay is to bet that it will not, effectively taking the other side, the role a bookmaker usually plays. Because you can do both, you can trade in and out of a position before the event settles. Back at odds of 3.0, watch the odds shorten to 2.5 as the market grows more confident, then lay at 2.5, and you lock in a position regardless of the final result. Do it the other way, lay first and back later, and the same logic applies.

Decimal odds carry an implied probability too. The rough conversion is one divided by the odds. Odds of 4.0 imply about a 25 per cent chance. Odds of 1.25 imply about 80 per cent. So the exchange price is doing the same job as the prediction-market price, just wearing different clothes.

The main UK-facing exchanges are Betfair, Smarkets and Matchbook. All are licensed by the Gambling Commission. If you want to see how the interface actually presents this order flow, our guide to how a Betfair ladder works walks through it.

How they’re actually the same idea

Strip away the packaging and the two are built on the same foundation.

Both are peer-to-peer. You are trading against other participants, not a bookmaker who has baked in a margin and would rather you did not win. The platform matches and charges a commission; the counterparty is another user.

Both turn a probability into a price. A prediction-market share at $0.60 and exchange odds of about 1.67 are saying the same thing: the crowd reckons the chance is roughly 60 per cent. Different notation, identical concept.

Both let you trade before resolution. This is the feature that separates them from a traditional fixed-odds bet. You are not locked in until the event ends. As new information arrives and opinion shifts, the price moves, and you can close, reduce or reverse your position at the new price. A win or a loss can be taken before anyone knows the actual result.

And in both cases, reading the market is really reading order flow. It is money moving a price. When a lot of buyers arrive, the price rises; when sellers dominate, it falls. Whether you are watching contracts change hands on a prediction market or watching money stack up on the back and lay side of an exchange, you are watching the same thing: supply, demand and the price they agree on.

The key differences

The shared foundation is real, but the practical differences matter when you decide what to use.

Feature	Prediction market	Betting exchange
Contract format	Binary yes/no share, priced 0 to 1	Back or lay at decimal odds
Regulator	US CFTC (Kalshi, Polymarket)	UK Gambling Commission (Betfair, Smarkets, Matchbook)
Settlement	Cash; Polymarket uses crypto/stablecoins	Cash in your account currency
Typical coverage	Broad: politics, economics, world events	Weighted towards sport
UK access	Polymarket not UK-legal; check each platform	Licensed and available

A few of these deserve a word. Coverage differs because of where each grew up. Polymarket in particular carries a vast range of global and political questions that UK exchanges simply do not offer. UK exchanges concentrate on sport, where the liquidity and the audience are. Regulation differs because prediction markets in the US sit under a financial regulator that treats the contracts as event derivatives, while UK exchanges sit under gambling law. And access differs as a direct result. A platform being legal and well run somewhere else does not make it legal to use from the UK.

Which one a UK trader can legally use

If you are in the UK, the straightforward answer is the UK-licensed betting exchanges: Betfair, Smarkets and Matchbook. They hold Gambling Commission licences, which means consumer protections, dispute routes and responsible-gambling tools apply.

Polymarket is not legal to use from the UK. We are not going to walk through ways around that, because there is no responsible version of that advice. If a platform is not licensed for the UK market, treat it as off limits and use one that is. Kalshi’s availability is US-focused as well; always check a platform’s own terms for who it accepts rather than assuming.

The honest framing here is simple. Where UK legality is in question, the safe and lawful route is a UKGC-licensed exchange, full stop.

The skill that applies to both

Here is the part that neither format changes: the price already reflects the crowd’s view, and beating it is genuinely hard.

Neither a prediction market nor an exchange hands you an edge. The number on the screen is the aggregate opinion of everyone who has put money down. To profit consistently you have to be right more often than that collective, after commission, which is a high bar. There is no signal to follow blindly, no feed that turns this into easy money. Anyone selling that is selling a story.

What does carry across both is the skill of reading order flow. Learning to see where money is moving, how quickly a price is shifting, and whether a move is backed by real volume or is thin and likely to snap back. That skill is the same whether the screen shows binary contracts or a back-and-lay ladder. The best way to build it is repetition on a market you understand, with small stakes or none at all while you learn.

You can practise reading an exchange market for free in our trainer, and there is more free material to start with on our free page. If you decide you want the full method, the plans are set out on our pricing page.

The honest bottom line

Prediction markets and betting exchanges are two versions of the same idea: peer-to-peer markets where the price is a crowd-estimated probability and you can trade before the result is known. They differ in contract format, regulator and access. For a UK trader, the lawful choice is a Gambling Commission-licensed exchange such as Betfair, Smarkets or Matchbook. Neither format gives you an edge on its own; the price already knows what the crowd knows, and the only durable advantage is skill built slowly.

This is general information, not financial or legal advice, and it is not tipping. Both are real-money gambling with real financial risk. Prices reflect probability, not certainty, and there is no guaranteed, risk-free or income-generating way to bet. You must be 18 or over. If gambling is affecting you or someone you know, free, confidential help is at BeGambleAware.org.