2026年10月17日
What Are Prediction Markets? How Yes and No Prices Work
Prediction markets turn real events into Yes and No prices. How a price becomes a probability, where the margin hides, and what to read before you buy.
A prediction market lets you buy Yes or No on a question about the real world, and the price tells you how likely the market thinks the answer is. Will Toronto hit 11 degrees today? Will Bitcoin finish the year ahead of gold? Every question gets a price, and every price is a probability with a margin attached.
Here's how that pricing works, how to find the margin yourself in about ten seconds, and what to read on a market before you put money on it. The examples come from the Predictions tab in our sportsbook, read on 17 October 2026.
The price is the probability
Everything else hangs on one idea. If the market prices Yes at 35%, it's saying the event happens about 35 times in 100. To turn that into decimal odds, divide 1 by the probability: 1 divided by 0.35 is 2.86, so a fair $10 bet on Yes would return $28.60 if it lands.
No is the other side of the same question. At 65% it converts to 1.54, and $10 on it returns $15.40. A well-run market is right about as often as its prices say across a lot of questions. On any single one, it can be wrong, and often is.
How the Predictions tab works
The tab sits next to Popular, Live and Upcoming at the top of the sportsbook. Markets are grouped into Films, Politics, Weather, Business & Tech, Crypto, Culture, Economy, Elections, Games, Geopolitics, Music, Sport and World.
Each market asks one question. Some have a single outcome, others split into several, and every outcome carries its own Yes and No. "Highest temperature in Toronto on October 17?" was offered as separate Yes and No prices for 10, 11 and 12 degrees Celsius. Questions run from one afternoon to more than a year: the weather board settles the same day, while "Bitcoin vs. Gold vs. S&P 500 in 2026" in the Crypto category closes on 1 January 2027.
Probability view or odds view
A toggle at the top of the board switches between two ways of showing the same market. Probability shows the market's own estimate. Odds shows the price you can actually buy.
On the Toronto market, the 11 degree outcome read Yes 48.5% and No 51.5% in the probability view. Those add up to exactly 100, as an estimate should. Flip to odds and the same outcome reads Yes 1.92 and No 1.81, and that's where the margin lives.
Find the margin in ten seconds
Take each price, divide 1 by it, and add the two results together.
Yes at 1.92 implies 52.1%, a little more than the 48.5% estimate.
No at 1.81 implies 55.2%, again above its 51.5%.
Together they come to 107.3%. Those 7.3 points over 100 are the margin, which is what it costs to use the market at all.
Two more from the same afternoon: Chicago's 56 to 57 Fahrenheit band was 1.48 and 2.51, or 107.4%, and New York's 60 to 61 band was 2.58 and 1.45, or 107.7%. Across the weather board, the margin sat at a little over 7%. The same test works on any sports market, and our guide to the vig walks through it with American odds.
Long shots have a ceiling
Very unlikely outcomes don't get bigger and bigger prices. On our board, Yes stops at 12.50, and the No side shows a dash because it isn't offered. "Will China unban Bitcoin by 2027?" sat at that cap with a probability of 2.65%. At 2.65%, fair odds would be about 37.7, so a long shot at the cap pays well under its own estimate. If you like long shots, this is the place the margin is biggest.
What gets a market
Anything with a clear answer and a date. Daily temperature highs, coin prices, awards, release dates and sports questions a normal book wouldn't carry. On 17 October the Sport category had Formula 1's action of the year, and the Crypto category had Bitcoin against gold against the S&P 500 for 2026.
Election and politics markets are on the board too. They're priced the same way and read the same way, and everything in this guide applies to them unchanged.
Prediction markets against a normal bet
Strip away the format and a Yes price is just odds. The difference is the question. A football match ends at the final whistle; a prediction market ends when its question is answered, which might be a temperature reading at the end of the day or a price on 31 December. So read the wording closely. "Highest temperature in Chicago" offered in two-degree bands isn't one bet on a number, and the 56 to 57 band loses if the high is 58.
Long-dated markets also tie up a stake for months. Bets here are held in dollars, so a $20 position on a 2027 question is still a $20 position when it settles, whatever the coin you funded it with did in the meantime. If you'd rather the rest of your balance didn't move with crypto prices either, our USDT casino guide covers holding a stablecoin.
Before you buy Yes or No
Read the closing time and the exact question, units and ranges included. Most disputes start there.
Run the margin test on the outcome you actually want, because it varies from market to market.
Check whether No is open. A dash means only one side can be bought.
Compare the probability view with your own estimate. If they agree, the margin means you're paying to agree with the crowd.
If you like the idea of setting the probability yourself, our bitcoin dice game is the same maths in miniature: you pick the chance on a slider, and the payout is 98% of the fair price on every roll.
Common questions
What are prediction markets?
Markets where you buy Yes or No on a real-world question. The price of each side is the market's estimate of how likely it is, with a margin added on top.
How do prediction markets work?
Each outcome has a Yes price and a No price. If the side you bought turns out right, you're paid at those odds when the question settles. If it doesn't, the stake is lost.
Are prediction market prices accurate?
They're estimates, and the odds include a margin. On our weather board on 17 October, Yes and No together came to about 107%, so the prices you could buy were a little worse than the estimates in the probability view.
Can you use crypto on prediction markets?
Yes. At Jacks Club the Predictions tab is part of the sportsbook, so a balance funded with Bitcoin, USDT or any other coin we take works there, with stakes shown in dollars.