Prediction markets like Polymarket and Kalshi, which processed $28 billion in trading volume by 2025, are under fire after revelations that 84% of users lose money. These platforms, designed to aggregate crowd wisdom on future events, have drawn comparisons to casinos from critics.

Arizona Congresswoman Yassamin Ansari recently lambasted the industry, stating "99.96% of users lose everything" while a tiny fraction profit. Her claims reference a December 2025 blockchain analysis showing 0.04% of Polymarket wallets captured 70% of all profits - totaling $3.7 billion.

The controversy has sparked legislative action, with Ansari co-sponsoring the BETS OFF Act to regulate these markets. While proponents argue prediction markets provide valuable forecasting data, the extreme wealth concentration among winners raises questions about their fairness and utility.