A trader opens Kalshi, looks at a contract asking whether the Federal Reserve will cut rates at its next meeting, and sees two numbers staring back. Yes is trading at 68 cents. No is trading at 32 cents. They add to a dollar, and that is not a coincidence. It is the whole mechanic.
Most people who arrive at prediction markets think of them as a kind of betting. You pick a side, you put money down, you win or you lose. That intuition is half right and half misleading. The reality is closer to a two-sided share market where every contract has a buyer and a seller, and the price of the yes share and the price of the no share are locked together by a piece of arithmetic that never breaks. Once you see that arithmetic, the rest of the platform stops feeling strange.
The dollar that does not move
Here is the rule that does all the work. On a binary market, one yes share plus one no share always settles at exactly one dollar (or one pound, or whatever the unit is). One side pays out the full unit, the other pays out zero. Which side wins depends on how the question resolves.
That single fact forces the prices to behave. If yes is trading at 68 cents, no has to be trading at roughly 32 cents, because anyone who could buy both sides for less than a dollar would be locking in free money at settlement. The market participants who hunt for those tiny gaps keep the two prices glued together. The technical name for this is no-arbitrage pricing, and our guide to prediction market arbitrage walks through what happens when the glue slips.
So when you see yes at 68 and no at 32, you are not looking at two separate bets. You are looking at one market priced from two angles.
Where the probability comes from
Why 68 cents and not 70? Because traders, collectively, think the underlying event has roughly a 68 percent chance of happening. The price is the probability. Multiply a yes share's price by 100, drop the decimal, and you have the market's implied probability in percentage terms.
This is not a forecast handed down by an analyst. It is the price at which buyers and sellers are willing to transact right now. If new information arrives, the price moves. If a hurricane forms, a Fed governor speaks, or a candidate drops out, you watch the yes price climb or fall in real time, and the no price moves in the opposite direction by the same amount. Our explainer on implied probability goes deeper into the maths, but the headline is simple: price is probability, and the two share prices are the two faces of the same forecast.
Buying yes is not the same as betting yes
This is where the share-versus-bet distinction matters. When you buy a yes share at 68 cents, you are not placing a 68-cent stake to win a dollar. You own a contract that is currently worth 68 cents and will eventually be worth either one dollar or zero. Until resolution, you can sell that share to someone else at whatever the market price happens to be.
So if the underlying event becomes more likely and the yes price climbs from 68 to 82, you can sell out at 82 cents and pocket the 14-cent gain without ever waiting for the question to settle. That is the part that catches new users off guard. You do not need to be right at the end. You only need the price to move your way at some point in between.
The same logic runs in reverse on the no side. Buying no at 32 cents is a position that profits if the event becomes less likely. If the no price climbs from 32 to 50, you sell out and bank 18 cents per share. The cap on your downside is the price you paid; the cap on your upside is what is left of the dollar after your entry.
Why buying no is different from selling yes (sort of)
A reasonable question. If yes plus no always equals a dollar, why does any platform bother offering both sides? Why not just let users buy yes or sell yes?
The short answer is that for most retail users, the two routes feel different even when they are mathematically equivalent. Buying a no share at 32 cents is a clean, capital-defined trade. You put down 32 cents per share, and the worst case is that you lose 32 cents. Selling a yes share short, on platforms that allow it, often requires a collateral posting closer to the full dollar to cover the worst-case payout. The economics resolve to the same place, but the cash flow shape and the user experience differ.
On Kalshi, a CFTC-regulated US venue, both sides of every binary market are offered as standard yes and no orders, and the platform handles the collateral mechanics behind the scenes. The same logic applies on Polymarket, whether you are on the CFTC-regulated Polymarket US product or the international platform that frames the contracts as outcome tokens rather than yes and no shares. Our comparison of Polymarket and Kalshi digs into the interface differences; for the purposes of this piece, treat them as the same underlying mechanic.
What happens at settlement
The moment of truth. When the market closes, the contract resolves yes or no, and one of the two share types pays a full dollar while the other pays zero. If you held yes shares on a market that resolved yes, every share in your account is now worth a dollar regardless of what you paid for it. If you paid 40 cents, you made 60. If you paid 95 cents, you made 5. If you held no shares on the same market, your shares are now worth nothing.
Resolution is meant to be mechanical. Each contract specifies a source of truth in advance, often a government data release, an official announcement, or a recognised news outlet's reporting, and the platform settles against that source. In practice, edge cases happen, and disputed settlements are the single most fraught corner of the industry. Our walkthrough of market resolution covers the corner cases. The simple version: when the answer is unambiguous, settlement is instant, and the dollar gets paid out to the winning side automatically.
What yes and no shares are not
A few quick clarifications, because the share framing carries some baggage from equity markets that does not apply here.
A yes share is not equity in anything. It does not give you voting rights, dividends, or any claim on a business. It is a contract that will be worth one dollar if a specific question resolves yes and zero otherwise. The word share is used because it trades like one, with bids and offers and a price that moves, not because it represents ownership of an underlying asset.
A yes share is also not a fixed-odds bet. With a bookmaker, your odds are locked in when you place the bet. With a yes share, your entry price is locked in, but the share's market value keeps moving until the question resolves, and you can exit at any point in between. That is the structural difference that makes prediction markets feel more like a securities market than a sportsbook, even when the underlying question is something like which team wins the Super Bowl.
And the legal wrapper around a yes share can differ by venue. Kalshi and the Polymarket US product both structure their contracts as CFTC-regulated event contracts settled in US dollars. Polymarket's international platform structures its as crypto-settled outcome tokens on Polygon and is geoblocked for US users. The economics rhyme across all of them; the legal wrapper depends on which venue, and which Polymarket, you are using. If that distinction matters to you, the event contract explainer sets out the regulated US version in detail.
Why the mechanic matters when you trade
Knowing that yes plus no equals a dollar changes how you read a market. Wide spreads between bid and ask on one side usually mean wide spreads on the other; thin liquidity is a property of the contract, not the side. If you see a yes share trading at 68 and no quoted at 35 cents, something is off, and either the order book is stale or you are looking at a fee-adjusted display. Either way, that is information.
It also changes how you size a position. A yes share at 5 cents is a long-shot, but it is a long-shot with capped downside, because the most you can lose is the 5 cents you paid. A yes share at 95 cents looks like a sure thing, but the upside is only 5 cents and the downside is 95. The price tells you both the probability and the payoff geometry in one number, which is a feature most other markets do not give you for free.
iPredicta tracks contracts across Polymarket, Kalshi and the regulated UK venues, and a lot of the discovery work boils down to spotting where the yes and no prices are sending a clearer signal than the headlines are. The mechanic underneath every market on the platform is the same one this piece just walked through: two prices, one dollar, one outcome.
Frequently asked questions
Why do yes and no prices always add up to a dollar?
Because one side of a binary contract pays out one dollar at settlement and the other pays zero, so the combined cost of holding both sides must equal the eventual payout. If yes and no together cost less than a dollar, traders would buy both, lock in the difference, and collect a risk-free profit at resolution. If they cost more than a dollar, traders would sell both. Those arbitrage flows pull the two prices back into line within seconds on liquid markets. The arithmetic is structural, not a platform rule. It holds on Kalshi, on Polymarket, and on any regulated venue running binary event contracts.
Can I lose more than I paid for a yes share?
No. Your maximum loss on a yes share is the price you paid for it, because the share can only settle at zero or one dollar. If you bought a yes share at 40 cents and the market resolves no, the share is worth zero and you have lost 40 cents per share. You cannot owe more than that. This is a meaningful structural difference from leveraged products or short positions, where losses can exceed the initial stake. It is also the reason capped-downside framing appears so often in prediction market explainers: the geometry of binary contracts genuinely limits how badly a single position can hurt you.
What is the difference between buying a no share and selling a yes share?
Economically they are equivalent, but the cash flow and collateral mechanics often differ. Buying a no share at 32 cents requires 32 cents of capital and caps your loss at that amount. Selling a yes share short typically requires posting collateral closer to the full dollar payout, because the platform needs to cover the worst case if the market resolves yes. On Kalshi and Polymarket, retail users almost always buy no rather than sell yes, because the capital efficiency is better and the interface is cleaner. Institutional and market-making accounts may use shorting tools that look different, but the resolution payoff is the same.
Does the price of a yes share mean the event will probably happen?
It means the market currently prices the event at that probability, which is not the same as a guarantee. A yes share trading at 68 cents implies a 68 percent chance, but markets can be wrong, especially in thin or new contracts where a handful of traders set the price. Over many markets and long time horizons, prediction market prices tend to track outcomes better than most alternatives, but any single price is a snapshot of consensus rather than a forecast from on high. Our comparison of markets and polls covers when prices are likely to be sharp and when they are likely to be noisy.
Can I sell a yes share before the market resolves?
Yes, as long as there is a buyer at a price you are willing to accept. Prediction markets are continuous, so you can exit a position any time the order book has liquidity. If you bought yes at 40 cents and the price climbs to 75 cents because new information made the event more likely, you can sell into that bid and bank the 35-cent gain without waiting for settlement. The risk is that thinly traded contracts may not have buyers at the price you want, and you may have to accept a worse fill to exit quickly. Our liquidity explainer covers that trade-off.