What Are Prediction Markets? Polymarket, Kalshi, and How They Work

Prediction markets let people buy and sell shares in the outcome of a future event — an election, an interest-rate decision, whether a coin hits a price, even who wins an award. The price of each share moves with the crowd's collective opinion, which makes the market itself a live, money-backed forecast. Crypto has turned what used to be a niche academic idea into one of the most talked-about corners of the space. This guide explains how they work, why crypto fits, and what to watch out for.

How a prediction market works

Every market is built around a question with a clear yes-or-no answer, such as "Will the Federal Reserve cut rates at its next meeting?" You can buy Yes shares or No shares.

Prices run from 0 to 100 cents (or 0% to 100%), and they represent the market's implied probability:

• A Yes share trading at 65¢ means the market thinks there's roughly a 65% chance the event happens.
• When the event resolves, the winning side's shares are worth $1 each and the losing side's are worth $0.

So if you buy Yes at 65¢ and the event happens, each share pays out $1 — a 35¢ profit. If it doesn't happen, those shares are worth nothing. You can also sell your shares before the event resolves, locking in a gain or loss as the odds move. That price — set by real people risking real money — is why economists often treat prediction markets as one of the better forecasting tools available.

Why crypto fits prediction markets

Prediction markets existed before crypto, but they were clunky, limited, and often shut down by regulators. Crypto removed much of that friction:

• Stablecoins make settlement easy. Most crypto-native markets are priced in a stablecoin like USDC, so you're betting in dollar terms without needing a bank for every trade.
• They're global and always on. Anyone with a crypto wallet can take part, 24/7, without a broker.
• Smart contracts hold the money. Instead of trusting a company to hold your stake and pay out, the funds sit in code on a blockchain and pay automatically when the result is confirmed.

To decide the actual outcome, crypto markets rely on an oracle — a system that reports real-world results back to the blockchain. The integrity of that oracle is central to whether a market can be trusted.

The main platforms

Two names dominate the conversation, and they take very different approaches:

• Polymarket is the largest crypto-native prediction market. It runs on a low-cost Ethereum network (Polygon), settles in USDC, and lets you keep your funds in your own wallet. Outcomes are resolved through a decentralized oracle. It became a household name during major elections, when its odds were quoted alongside traditional polls.
• Kalshi is a US-based, federally regulated exchange (overseen by the CFTC). It uses ordinary US dollars and bank transfers rather than crypto, which makes it feel more like a brokerage. It's a useful contrast that shows prediction markets are not only a crypto phenomenon.

We compare these two in detail in Polymarket vs Kalshi, and line up the leading platforms side by side on our best prediction markets page.

What people actually trade

Markets cover a huge range of topics:

• Politics — elections, leadership changes, policy votes.
• Economics — interest rates, inflation prints, jobs numbers.
• Crypto — whether Bitcoin or another coin hits a price by a date.
• Culture and sports — awards, sporting results, and one-off events.

The crypto-price markets are popular with people who already follow the market and want a defined-risk way to express a view.

The risks and the rules

Prediction markets are exciting, but they are speculation, and the risks are real:

• You can lose your entire stake. A losing share goes to zero. There is no "it'll bounce back."
• Thin markets move sharply. Niche questions may have few participants, so prices can be volatile and hard to exit at a fair value.
• Resolution can be disputed. If the wording of a question is ambiguous, deciding the outcome can get contentious.
• Eligibility and legality vary by where you live. Access rules change often and differ by country and US state. Some platforms restrict or block users in certain regions. Always check the current rules for your location before signing up.

Treat prediction markets as a small, defined-risk part of how you follow the world — not a way to get rich, and never with money you can't afford to lose.

Key takeaways

• A prediction market lets you buy Yes/No shares in a future event; the price reflects the crowd's implied probability.
• Winning shares pay $1, losing shares pay $0, and you can trade out before resolution.
• Crypto fits because stablecoins, wallets, and smart contracts make global, automatic settlement easy.
• Polymarket is the crypto-native leader; Kalshi is a US-regulated, dollar-based alternative.
• It's real speculation — you can lose everything, markets can be thin, and access rules vary by location.

This article is for education only and is not financial, legal, or investment advice. Prediction markets may not be available or legal where you live.