A founder comparing two prediction markets before planning next year’s borrowing might find different prices for what looks like the same rate-cut question. Contract wording, trading costs and the orders available can all explain the gap.
Compare platforms on eligibility, rules and costs before you consult any ranking. The best fit depends on your purpose and jurisdiction, and this guide is educational rather than financial or legal advice.
The CFTC describes event contracts as often yes-or-no instruments and warns that all speculation involves risk.
Key Takeaways
- Check eligibility first. Your location and each venue’s member terms decide which platforms you can consider.
- Learn before you fund. Watching markets or using play money lets you learn without risking cash.
- Compare complete costs. Fees, spreads, funding charges and exit costs matter more than a headline probability.
- Read the full rules. Contracts with similar titles can ask different questions and settle differently.
- Protect business funds. Keep payroll, tax reserves and other essential money out of speculative trading.
Build a Shortlist You Can Use
A typical binary event contract pays a fixed amount if a defined outcome happens and nothing if it doesn’t, subject to its settlement rules. Decide first whether you want to learn from market prices or commit money, because those goals point to different venues.
| Platform | Type of participation | Cost model | Main qualification |
| Kalshi | Real-money event contracts | Trading fees with market-specific exceptions | Access outside the United States is subject to its member agreement |
| Polymarket US | Real-money event contracts in a separate US app | Standard taker fees, before any rebates | US residents are directed to this separate product |
| Polymarket (international) | Real-money event contracts | Category-based taker fees; makers pay no trading fee | International service with geographic restrictions; VPN bypass prohibited |
| Manifold | Play-money forecasting in mana | Free M1,000 starting balance; mana cannot be converted to cash | Practice and learning, not cash returns |
Inclusion in the table does not establish your eligibility for any venue.
Your location. Check each venue’s current member terms before registering or funding an account. The US app and the international service are separate products with separate support teams, and the international service prohibits using VPNs or similar tools to get around its geographic restrictions.
Your purpose. If you only want to follow prices around an announcement, publicly available market information may be enough. For forecasting practice, Manifold offers noncash mana, so decide whether real-money participation adds anything you need.
How rankings are built. For background reading, the best prediction markets comparison from Prediction Markets Best scores platforms on nine published criteria using operators’ own documents and regulator registers. Funded-account tests appear only where a review includes a dated test record, and unassessed criteria stay unrated.
Use the assessed criteria to narrow your shortlist, then confirm the relevant terms with each venue.
Compare the Full Cost of a Trade
A taker places an order that immediately matches an existing offer. A maker places an order that waits on the order book, the list of buy and sell orders, for someone else to match it, and fee treatment depends on the venue and order type.
Trading fees. For comparison, take 100 contracts at $0.50 each, a $50 position. Kalshi’s standard fee works out to $1.75 on that order, with market-specific exceptions, so the purchase costs $51.75 before any other charge.
Other venues price the same order differently. Polymarket US quotes standard taker fees before any rebates, while Polymarket’s international service sets taker fees by market category and charges makers nothing, so pull each venue’s current fee table for the exact contract you would trade.
These examples exclude funding and exit costs. They also don’t establish that identical contracts or executable quotes exist across venues.
The price you can execute. On the international service, the displayed price normally shows the midpoint of the bid-ask spread, and the last traded price replaces it when the spread exceeds $0.10. That midpoint may differ from the price you can trade at and is not an objective probability.
For a purchase, check the best ask, meaning the lowest offered selling price, and the quantity available at that price. Don’t add the spread again to a price that is already executable, and remember that high platform-wide volume doesn’t guarantee enough orders in a particular contract.
Funding and exit costs. Record any deposit and withdrawal charges, fees on a closing trade and collateral conversion costs. Enter current figures from each venue’s own documents into your own worksheet and check which costs each calculation includes.
Check Contract Rules and Evidence
Read beyond the title. Kalshi warns that a rules summary does not contain the full contract rules. Two hypothetical markets, a rate cut at the next meeting and any cut by year-end, ask different questions despite sharing a theme.
For each contract, identify what is measured, which source settles the outcome, the deadline and its time zone and how an ambiguous result is handled. Check for exceptional settlement clauses as well as the usual win-or-lose outcome.
Check the evidence. When an announcement arrives, read the official release rather than treating the final market price as confirmation. Eligibility also deserves a recheck: on October 9, 2026, the CFTC published a proposal, not a final rule, that would expressly include event contracts in the definition of swap.
State and federal authorities continue to disagree over who regulates these contracts, so US access is not uniformly settled.
Keep a decision log. Picture a café owner weighing a second location. She records the displayed probability of a rate cut beside three budget scenarios (cut, hold and rise) and writes down the assumptions behind each one.
After the announcement, she revisits the entry to see which assumptions held. This tracks her reasoning; it does not show that markets improve business results.
Protect business funds. A real-money position can lose its entire stake, you may not be able to exit when you want and it may fail to offset the business risk you’re trying to manage. Keep payroll, tax reserves and the money that supports your business cash flow out of speculative trading.
Conclusion
For a founder, a prediction market price is most useful as one input to planning, not a forecast to bet the business on. Confirm eligibility, price the full trade and read the complete rules before funding any account.
Save the full contract rules and fee schedule alongside your decision log, so you can see later what you knew when you decided.
FAQ
Can a business use prediction market prices without trading? Yes. Public market prices can inform planning scenarios without any account or money at risk.
Why might two platforms price the same question differently? Contract wording, settlement sources, fees and the orders available can all differ, even when headlines look identical.
Is the displayed probability the price I would pay? Not always. Some venues display the bid-ask midpoint, while an immediate purchase fills at the best ask.
Are prediction markets settled law in the US? No. The CFTC’s October 2026 swap-definition proposal is not yet final, and state and federal authorities still dispute oversight.
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