Two platforms are battling to define the future of prediction markets in America, and they couldn’t be more different. Kalshi operates as a federally regulated exchange under CFTC oversight, housing trade contracts and payments in a centralized model. Polymarket functions as a decentralized platform using USDC cryptocurrency with an on-chain order book. These fundamental differences shape everything from market structure to user access.
The rivalry becomes clear when examining what each platform does best. Kalshi pulls 89% of its revenue from sports betting markets and thrives on high transaction frequency with smaller individual amounts. Its user activity swings dramatically with sports seasons, and open interest surged during the 2025 NFL season to reach all-time highs. Meanwhile, Polymarket demonstrates strength in politics, geopolitics, and crypto categories, prioritizing information density and market depth over transaction volume. The platform’s open interest peaked at $500 million during October 2024 election coverage.
Their growth strategies reveal opposing philosophies. Kalshi builds distribution channels through partnerships like NHL deals and Robinhood access, bringing products directly to users. Polymarket constructs underlying infrastructure and hopes developers will spontaneously create applications on top. One pursues retail channel maturation while the other bets on decentralized ecosystem formation.
Market coverage reflects these different approaches. Kalshi offers 350,000+ active markets spanning sports, politics, economics, crypto, and weather. Polymarket International provides broader coverage including culture, world events, earnings, and real estate, though Polymarket US currently operates sports-only markets with hundreds of thousands on the waitlist.
The numbers tell an interesting story. Kalshi maintains $2.7 billion in weekly volume with 53% market share and deepest liquidity in major US sports contracts. Polymarket International generates $2.1 billion weekly with 47% market share and dominates political and crypto market liquidity. Together they produced $1.63 billion across Super Bowl 60 markets, the largest event window in prediction market history.
Fee structures differ too. Polymarket operates without trading fees but charges commission on winning contracts, often proving cheaper for trades priced between 30¢ and 70¢. Kalshi uses tiered per-contract fee schedules while accepting multiple payment methods including cryptocurrency.
Spot trading offers immediate ownership of assets and typically settles within two business days, which underscores how quickly users on both platforms can take or close positions using spot markets.
