How prediction market odds work
Updated
A prediction market asks a yes-or-no question about a future event. You buy Yes or No shares. The price of a share is the market's estimate of how likely that answer is. Syndicate's prediction markets come from Polymarket.
The price is a probability
A share always costs between $0 and $1. Read the price as a chance. A Yes price of $0.62 means the market puts the chance of Yes at about 62%. Discover shows it that way, as a whole percent.
Yes and No trade in one order book. The No price is roughly one minus the Yes price. The price you pay when you buy is the best price someone is selling at right now, which can sit a little above the middle of the book.
What a share pays
When the market resolves, each winning share pays $1. Each losing share pays nothing. So the number of shares you hold is the amount you receive if you are right.
The ticket works this out for you. It divides your amount by the price, rounds down to the cent, and shows the price, the share count and what you get if you are right.
Decimal odds
Decimal odds are one divided by the price. They tell you how much a winning bet returns for each dollar staked, stake included. Syndicate shows them as a multiplier, such as ×1.61.
Here is a worked example.
- Yes costs $0.40. That reads as a 40% chance.
- The decimal odds are 1 ÷ 0.40 = ×2.50.
- You put in $20 and get 50 shares, because 20 ÷ 0.40 = 50.
- If Yes wins, the 50 shares pay $50. That is $20 × 2.50, a profit of $30.
- If No wins, the shares pay nothing and you lose the $20.
Some markets charge a fee on buys. Fees come out of the amount you enter, so you may get slightly fewer shares than the simple sum shows.
Placing an order
The smallest market buy is $1. A market buy fills in full straight away or not at all, so you never end up with half an order. You can also place a limit order at your own price. It waits on the book until someone takes it.
Combos
A combo joins several picks into one bet. It pays only if every pick wins. You need at least 2 picks, and you can add up to 50.
While you build a combo, the slip shows estimated odds, marked as approximate. The estimate multiplies the odds of each pick. Two picks at ×2.00 each come to about ×4.00. The real price comes from a live quote, which is good for about five seconds.
How markets resolve
Syndicate does not decide outcomes. Polymarket markets resolve through UMA's optimistic oracle. Someone proposes an answer, and it can be disputed before it becomes final. Once a market resolves, winning shares are redeemed for $1 each and losing shares are burned.