Is Polymarket the largest prediction market?

Polymarket is indisputably the largest prediction market by volume. During the 2024 US presidential election alone, over $3.7 billion in contracts traded across its platform—making it one of the most liquid derivative markets for event-based trading.

Volume Metrics

Polymarket's scale is staggering. Average daily volume hovers around $20-50 million during quiet news cycles. During election weeks or major event announcements (Fed decisions, policy changes), volume spikes to $500 million+ in a single day. The 2024 election presidential contract alone processed over $1 billion in daily volume at peak times.

Kalshi, the second-largest US-regulated platform, processed roughly $1 billion total across all markets in 2024. PredictIt, a centralized betting exchange, handled less than $100 million annually. Polymarket's volume exceeded all other prediction markets combined.

Why Polymarket Dominates

Multiple factors created this concentration:

Geographic reach: Polymarket operates globally. While its US operations faced restrictions from 2022-2025, the platform served users worldwide. Kalshi only operates in the US. PredictIt also restricts to US players. Geographic arbitrage matters—international traders often provide liquidity for major events.

Market variety: Polymarket offers 1,000+ active markets across politics, sports, economics, crypto, pop culture, and science. Kalshi focuses on sports and economics. PredictIt limits offerings. More markets attract different trader types.

Liquidity begets liquidity: Markets with $10 million in buy/sell orders attract more traders than markets with $100,000. Polymarket's size meant deeper order books, which attracted serious traders (institutions, hedge funds, betting syndicates) who needed liquidity. Once major players arrived, retail traders followed.

Decentralized structure: Polymarket's blockchain-based design meant no single point of failure, no account freezes due to regulatory pressure, and lower operational costs. This translated to lower fees, which meant traders had no reason to switch to alternatives.

Speed and UX: Polymarket's interface is faster and simpler than competitors. This matters enormously. Traders moving millions need sub-second execution. Polymarket on Polygon delivers that.

Regulatory arbitrage: When the CFTC cracked down on Polymarket in 2022, forbidding US users, the platform didn't collapse. It continued operating globally while accepting that US restrictions were temporary. This contrasts with PredictIt, which was always hamstrung by regulatory caution, and Kalshi, which fought regulators directly and faced injunctions in multiple states.

The Competitive Landscape

Kalshi: CFTC-regulated, operates in the US. Focuses on NFL, soccer, economic data releases, and election betting. Gained regulatory approval after years of litigation. Volume is growing but still trails Polymarket. Kalshi pays 4% annual interest on balances (a fee advantage). State-level battles persist.

PredictIt: