Polymarket’s trading volume fell to $10.2 billion in April 2026, down 8.9% from March’s $11.2 billion, marking its first monthly decline since August 2025. The slip comes as rival Kalshi surged 13% to $14.8 billion in the same period, capturing market share in a sector now worth $29.8 billion monthly. The shift reflects mounting regulatory pressure on prediction markets, particularly around insider trading concerns that have drawn scrutiny from Senator Elizabeth Warren and the US Commodity Futures Trading Commission.
Regulatory Pressure Intensifies on Prediction Markets
The CFTC has maintained that event contracts fall under its jurisdiction as a type of swap, requiring federal employee compliance with insider trading restrictions. In March 2026, Senator Warren and 40+ Congressional representatives sent a letter to the CFTC emphasizing that federal employees understand existing prohibitions on prediction market insider trading, especially in geopolitically sensitive markets like wars and energy prices. This regulatory focus has created operational friction for platforms. Polymarket itself faced a CFTC settlement in 2022 that forced it to exit US operations entirely, only returning in December 2025 with a US-dedicated app using siloed liquidity separate from its global platform.
Kalshi Gains Ground Amid Sector Expansion
While Polymarket declined month-to-month, the broader prediction markets sector grew 12.4% from March to April, reaching $29.8 billion in total volume. Kalshi’s 13% surge to $14.8 billion positions it as the volume leader, suggesting market participants are rotating capital toward platforms perceived as more aligned with regulatory expectations. The competitive dynamics reflect growing institutional confidence in prediction markets as price discovery mechanisms, even as legal uncertainty persists. Kalshi has not faced the same regulatory constraints as Polymarket, giving it operational advantages in the US market.
State-Level Actions Compound Compliance Challenges
Beyond federal scrutiny, Wisconsin Attorney General Josh Kaul filed lawsuits in April 2026 against prediction market platforms, alleging violations of state sports betting laws. This multi-jurisdictional enforcement approach signals that regulators view prediction markets as distinct from traditional betting but subject to similar guardrails. Polymarket’s April decline likely reflects both CFTC pressure and uncertainty around state-level actions, which could fracture the platform’s US user base if enforcement spreads across states. The company’s decision to silo US liquidity from global pools may limit its competitive edge against Kalshi, which operates under a different regulatory framework.
What Comes Next for Market Leadership
Polymarket’s volume recovery depends on regulatory clarity from the CFTC and the resolution of state lawsuits. Emerging competitors like Prophet, an AI-native prediction market platform, and tools like MoonPay’s integration options add further competition. If insider trading rules remain ambiguous or enforcement intensifies, Kalshi’s current market lead could solidify. The April data suggests the prediction markets sector is consolidating around platforms with clearer regulatory pathways rather than pure liquidity depth.
