Prediction markets often quote different prices for the same event. A question can show Yes at 58 cents on one venue and 63 cents on another, a five-point gap that violates the textbook law of one price. In theory, buying the cheap Yes on one platform and the cheap No on another would create a risk-free $1 payout for less than $1. In practice, that edge rarely survives real-world costs.
Seven forces keep prices apart. Fees and spreads reduce thin margins; resolution language may settle on different official sources, deadlines, or time zones; shallow liquidity causes slippage; different user bases and geographic access slow information flow; settlement currency adds conversion and bridge costs, with Kalshi settling in US dollars and Polymarket in USDC; capital remains locked until resolution; and news speed plus withdrawal friction delay arbitrage. Once illustrative costs are subtracted, a four-cent apparent profit can shrink to between zero and one cent, while resolution mismatch can turn a supposed 96-cent position into a loss.
Venue rules matter too. Dexsport, for example, lists arbitrage betting as prohibited conduct alongside automated betting software. Its prediction markets settle only in stablecoins, price shares between 1c and 99c, and in sampled markets display a Yes plus No total of 101c to 102c. The platform operates through Dexapp LTD under an Anjouan licence and validates outcomes within 24 hours.
For investors tracking interest rates, inflation, growth and crypto regulation, several venues stand out in 2026. Kalshi is a CFTC-approved event contract exchange with deep markets on CPI, GDP, unemployment, and Fed decisions, reporting more than $80 million in trading volume on its September FOMC market. ForecastEx, a CFTC-registered designated contract market and clearinghouse, offers FOMC, CPI, GDP, and Treasury yield contracts settled to official BLS, BEA, and Federal Reserve releases, with deeper order books and tighter spreads on core macro variables.
Polymarket is the largest crypto-native venue, settling in USDC on-chain and focusing on crypto regulation, stablecoins, ETFs, and enforcement. As of October 6, 2026, it listed about 500 active crypto policy markets with more than $26.3 million in cumulative trading volume in that category. Other platforms add specialized signals: Metaculus offers free reputation-based long-horizon forecasts; PredictIt focuses on political outcomes under a CFTC no-action letter with $3,500 position limits and a 10% fee on profits; Manifold Markets provides play-money social sentiment, with one Fed rate-hike contract moving from 46% in late August to 94% by mid-September; and Robinhood operates as a CFTC-registered futures commission merchant, trading 13.6 billion event contracts in Q2 2026 and earning about $156 million in revenue.
Persistent price gaps are not just trading opportunities. They can signal unclear resolution rules, thin liquidity, or information that one crowd has already absorbed. The practical conclusion is to compare rules first and prices second, and to cross-check major signals against official Fed, BLS, BEA, and regulatory releases.
