How Prediction-Market Prices Work: What a 62¢ Contract Tells You

Open a prediction market and every contract shows a price between 1¢ and 99¢. It’s tempting to read that number the way you’d read a stock quote — as what the thing is “worth” right now — but a prediction-market price is doing something different. It’s the market’s running estimate of how likely an outcome is, expressed in cents instead of a percentage. A 62¢ contract isn’t saying “this costs 62 cents.” It’s saying “enough traders are willing to back this at a price implying roughly 62% odds that it happens.”

That distinction matters because it decides what you can and can’t conclude from the number on the screen.

The payout is binary: $1 or $0

Every contract on a market like Polymarket US settles one of two ways once the underlying event resolves: it pays $1 per contract if the outcome happens, and $0 if it doesn’t. There’s no partial credit and no sliding scale — the settlement value is fixed regardless of how close or lopsided the actual result turns out to be. The CFTC’s own consumer guidance on this contract structure describes exactly this mechanic: a payout that depends entirely on the outcome of a yes/no proposition, with nothing in between (CFTC/SEC Investor Alert on binary options).

Because the only two possible endpoints are $1 and $0, the price you see before settlement has to sit somewhere on that line — and where it sits is the market’s collective bet on how the coin is likely to land. If a contract trades at 62¢, that price only makes sense as an estimate of probability: buyers are willing to pay up to 62¢ for a shot at $1, and sellers are willing to accept 62¢ to give up that shot, which is exactly the equilibrium you’d expect if the crowd believes the event is roughly 62% likely to happen.

Why “implied probability” is the right way to read it

Treat the price as the market’s probability estimate, not as a fact about the world. A few consequences follow directly from that:

• The price moves as new information arrives, the same way odds shift before a game. A contract at 30¢ this morning can sit at 55¢ by evening if something changes the crowd’s read on the outcome — nothing about the underlying event has to have happened yet for the price to move, only the market’s belief about it.
• A high price is not a promise. A contract at 90¢ is pricing in roughly nine-in-ten odds, which also means roughly one time in ten, a 90¢ contract should lose. If you only ever traded 90¢ contracts and lost once in nine tries, that’s not a broken market — that’s the market working as designed. The price tells you the odds it’s pricing in, not which side is “correct.”
• A contract can be mispriced relative to the true probability, and markets don’t self-correct instantly. Low-liquidity markets, markets dominated by a handful of traders, and markets on unusual or hard-to-research topics are all more prone to prices that drift away from what careful research would suggest the real odds are. The price is a crowd estimate, and crowds can be wrong, slow to update, or thin enough that one large trade moves the number without moving the underlying reality at all.
• Long-shot contracts have their own known bias. Research on prediction markets and betting markets more broadly has documented a persistent pattern — long-shot outcomes (contracts priced low, in the 5–15¢ range) tend to be priced slightly higher than their eventual win rate actually justifies, while heavy favorites tend to be priced slightly lower than they should be. It’s a small effect, not something you can reliably trade around, but it’s a reason a 10¢ price shouldn’t be read as a precise 10% probability — more like “roughly 10%, with a documented tendency for prices in this range to run a bit rich.”

None of this means the price is useless — it’s usually a reasonable, continuously updated aggregate of what a lot of people with money on the line currently think. It just isn’t a certainty, and a contract’s price tells you what the market believes, not what will happen.

Spread and fees quietly cost more on small trades

A price you see quoted is almost never the exact price you’ll pay and the exact price you’d receive if you sold back a moment later. The gap between what a buyer pays and what a seller receives — the spread — exists because market makers and other liquidity providers need some margin to be willing to stand ready on both sides of a trade. On a liquid, heavily traded contract, that spread might be a fraction of a cent. On a thin, low-volume market, it can be several cents wide, which is itself a real cost: buying at 63¢ and immediately being able to sell only at 60¢ is a 3¢ loss with the underlying probability having moved nowhere.

Trading fees add a second, separate drag. Polymarket US, for example, charges takers a fee calculated from the contract’s price rather than a flat percentage — we’ve run through the exact formula and what it costs at different prices elsewhere on this site. The short version that matters here: that fee is close to proportional to trade size, so it doesn’t shrink much as a fraction of your trade just because the trade itself is small. A $5 position and a $500 position pay roughly the same fee rate, which means the $5 trade’s fee is a much bigger bite out of its already-small potential return. Spread works the same way — a fixed number of cents lost to the spread is a far bigger percentage hit on a $5 trade than on a $500 one.

Put together, spread and fees mean a contract’s displayed price is the start of the math, not the end of it. A 62¢ contract that looks like a clean 62%-implied bet can, after the spread you actually pay to get in and the fee charged on the fill, behave more like a 64¢ or 65¢ entry once the full cost is counted — which matters most on the smallest trades, where those fixed-ish costs are hardest to absorb.

What this means in practice

A prediction-market price is a real, continuously updated number worth paying attention to — it’s generally a better-informed estimate than a guess pulled out of thin air, because it reflects money actually at risk rather than just an opinion. But it’s an estimate, built by an imperfect, sometimes thin, sometimes biased crowd, settling to one of exactly two outcomes with nothing in between. Reading 62¢ as “the market thinks roughly 62%,” rather than as “this is worth 62 cents” or “this is 62% likely to be true,” is the difference between using the number correctly and over-trusting it.

If you’re putting real money — or a referral credit — behind a contract, the price is the best public estimate of the odds you’re accepting, the fee schedule tells you what that trade actually costs on top of the quoted price, and neither one tells you how the event will actually turn out.

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