Arbitrage Between Prediction Markets: Why One Question Trades at Two Prices

Open the same question on two prediction venues, and the quotes often disagree. One platform might show Yes at 58 cents while another asks 63 cents for what looks like an identical outcome.

Textbook economics says arbitrage should erase that difference within minutes. Real prediction market prices can stay apart for days or weeks, and the reasons say a lot about how these venues work.

Below: what two prices for one question mean, seven forces that keep them apart, the arithmetic once costs enter, and how venue rules treat prediction market arbitrage.

What Two Prices for One Question Mean

Each share pays $1 if the outcome happens and zero if it fails. Its price in cents doubles as an implied probability, so Yes at 58 cents means the crowd puts the chance near 58%.

When two venues quote one event at 58 cents and 63 cents, their crowds disagree by five percentage points. Economists call it a breach of the law of one price.

Arbitrage, in its classic form, means a purchase of the cheap Yes on one venue and the cheap No on the other. If the pair costs under $1, it pays $1 whichever way the event resolves.

Illustrative figures, not live quotes.

On paper, Yes at 58 cents on Venue A plus No at 38 cents on Venue B costs 96 cents for a $1 payout. Four cents of apparent profit rarely survives contact with the real world.

Seven Forces That Keep Prices Apart

Each force below shaves something off that four cents, and several together can erase it.

1. Fees and Spreads

Every venue takes its cut somewhere. Some charge an explicit fee per contract, while others build the cost into a Yes plus No total above $1. Two venues mean two sets of charges against one thin margin.

2. Resolution Language

Markets with similar titles may settle on different rules. One might resolve on an official announcement, another on a named data source or "a consensus of credible sources".

Deadlines can split outcomes too, with one venue in UTC and another in Eastern Time. Our explainer on resolution rules shows how one phrase can flip a payout.

3. Liquidity Depth

Quoted prices cover the first few dollars. In a shallow market, a larger order moves the price, so 58 cents on screen can become 60 or 61 cents after a modest fill.

4. Crowd Composition and Geography

Each platform draws its own user base. Access varies by country and by licence, so a US-regulated exchange and an offshore crypto venue may react to news at different speeds. Users of one venue often cannot reach the other, which shrinks the pool of people able to close the difference.

5. Settlement Currency

Kalshi settles in US dollars, Polymarket in USDC, and other crypto venues in a choice of stablecoins. Value moved between them meets conversion fees, network or bridge fees, and delay.

6. Capital Lock

Money committed to a market stays there until resolution. Four cents on a 96-cent outlay over 18 months works out near 2.8% a year before fees, a thin return for capital tied up that long.

7. News Speed and Withdrawal Friction

News reaches one crowd before the other. By the time a user funds a second account, the price may have moved. Withdrawal reviews, validation windows and network confirmations add further delay.

The Arithmetic Once Costs Enter

Return to the 96-cent pair and subtract what each step costs. The figures below show plausible ranges for a small position, not quotes from any venue.

Illustrative figures, not live quotes.

After those deductions, the four cents falls to somewhere between zero and one cent. Resolution risk then enters the picture.

If the two venues settle the same question differently, both legs can lose. Such a position, built to make four cents, can cost 96 cents. Traders with enough capital to close price differences weigh that lopsided risk, which explains why two prices persist.

Our breakdown of the Yes-No spread covers the cost side within a single venue.

How Venue Rules Treat Arbitrage

Prediction venues and sportsbooks often restrict positions on both sides of one outcome in their terms, and each operator enforces those rules account by account.

Dexsport lists arbitrage betting as prohibited conduct, next to automated betting software. Its prediction markets settle only in stablecoins, price shares between 1 and 99 cents, and pay $1 per correct share.

Last verified: September 2026

Dexsport operates through Dexapp LTD under an Anjouan licence. Read the conduct section of any venue's terms before you hold positions on one question across two platforms.

What a Price Difference Can Tell You

Two prices hold information even for users who never plan an arbitrage. Wide splits often point to unclear resolution language, thin liquidity, or news that one crowd has absorbed first.

Compare the rules first and the prices second. Our platform comparison sets out how three venues differ on settlement and access.

Conclusion

One question trades at two prices because each venue prices its own version of the question. Fees, resolution language, liquidity, user base, settlement currency, locked capital and news speed all push quotes apart, and together they leave little of an apparent four-cent edge.

Resolution mismatch adds a risk far larger than the margin on offer, which keeps many large traders away. Several venues, Dexsport among them, also prohibit arbitrage betting outright.

Treat a price split as a prompt to reread the rules. Check the law where you live, trade only at legal age, and expect that KYC or AML checks may apply. Responsible gambling means stakes you can afford to lose.

Disclaimer: The information here is provided for general purposes only and is not legal, tax, investment, or financial advice. Figures in the worked examples are illustrative, not live quotes. Prediction markets and betting involve risk, platform terms change, and rules vary by country, so check the law where you live. Please trade responsibly, within your means, and only if you are of legal age.