Crypto Event Contracts: Costs, Odds, and Expected Value Explained
A crypto event contract’s price is its implied probability. A YES share at 40 cents implies a 40 percent chance the event resolves true, and it pays one dollar if it does. Your expected value is simply the true probability times the payout minus what you paid, minus fees. If your honest estimate beats the price after costs, the bet has positive expected value. If not, it doesn’t.
How price maps to odds
Read the price as a percentage. YES at 0.25 means the market prices a 25 percent chance; YES at 0.80 means 80 percent. NO shares cost one dollar minus the YES price, so if YES sits at 0.25, NO sits near 0.75. The payout is fixed at one dollar per winning share, which makes the return easy to compute: buy YES at 0.25, win, and you collect a dollar for a 0.75 profit per share, a return of three times your stake before fees.
The expected-value formula
Expected value, or EV, is the engine behind every rational bet. The plain version: EV per share equals (your estimated probability of YES times the one-dollar payout) minus the price you paid. Suppose you believe an event is genuinely 50 percent likely but the market prices YES at 0.40. Your gross EV is 0.50 minus 0.40, or 0.10 per share, a 10-cent edge before costs. The hard part isn’t the arithmetic. It’s being honest about that 50 percent, because most people overrate their own read.
The fees that eat your edge
Costs come in a few shapes. Many venues charge a trading or settlement fee per contract, sometimes scaled to how far the price sits from the extremes. There may be a withdrawal fee when you cash out, and on crypto-native platforms, network gas costs on top. Subtract every one of these from the gross EV above. A 10-cent edge can shrink to a few cents once a per-contract fee and a settlement charge come out, and a marginal-looking bet can flip to negative.
The spread, the quietest cost
The gap between the best buy price and the best sell price is the spread, and it’s a cost you pay twice if you trade in and out. On a heavily traded contract the spread might be a cent or two. On a thin one it can be a dime, meaning you’re down ten percent the instant you enter. I always check the spread before I check the headline fee, because on illiquid markets the spread usually hurts more. For broader context on how these costs compare across event-based venues, the overview of prediction markets lays out the fee structures side by side.
A worked example
Say a contract asks whether a coin closes above a set level by month-end. You think it’s 55 percent likely. YES trades at 0.48 with a 1-cent spread, and the venue charges a 2-cent settlement fee on winners. Buying at the offer means paying roughly 0.485. Your gross EV is 0.55 minus 0.485, about 0.065 per share. Net of the expected settlement fee, you’re closer to 0.05. Still positive, but thin enough that a small error in your probability estimate erases it entirely. That’s the reality of these markets: edges exist, but they’re narrow.
Where edges actually come from
Positive EV doesn’t appear by accident. It usually comes from one of three places: information the crowd hasn’t priced yet, a structural overreaction to news, or simple mispricing on a thinly watched contract. The first is rare and fleeting in crypto, where information moves fast. The second requires discipline to act against the herd. The third needs you to be in markets too small for sharper traders to bother with, which brings its own liquidity risk. None of these is a reliable paycheck.
Frequently asked questions
How do I convert a contract price to odds?
Read the price directly as a probability. YES at 0.30 implies a 30 percent chance and pays one dollar if correct, giving roughly 2.3-to-1 on your stake before fees. NO costs one dollar minus the YES price.
What’s a realistic edge on these markets?
Small. After spread and fees, even a well-judged bet might carry a few cents of EV per share, and many trades that look favorable are break-even once costs are counted. Treat large claimed edges with suspicion.
Do fees really change the outcome that much?
On thin margins, yes. A 2-cent fee on a 5-cent gross edge cuts your expected value by a large fraction. Always subtract every fee and the spread before deciding a bet is worth taking.
Is positive expected value the same as guaranteed profit?
No. Positive EV means the bet is favorable on average across many repetitions. Any single contract can still lose, and a run of losses is normal even with a real edge. Outcomes are never guaranteed.
Are there age or eligibility rules?
Yes. Regulated venues require users to be 18 or 21 depending on jurisdiction and verify identity. Check the rules where you live, and only commit money you can afford to lose.
What to do next
Before any trade, write down your honest probability, read the price as the market’s probability, and subtract the spread and every fee from the difference. If a real edge survives that, the bet may be worth a small position. If it vanishes, skip it. The math is simple; the discipline to act on it, and to size stakes you can lose, is the part that separates careful traders from hopeful ones.
By Daniel Reyes, prediction-market analyst focused on pricing and expected value. Last updated June 2026.