Prediction markets US iGaming 2026 — Kalshi, Polymarket and the threat to sportsbooks

Kalshi and Polymarket turned the 2026 World Cup into a stress test for a new category boldly competing with the entire sportsbook and casino brand market. By that point, Kalshi was already offering sports contracts to US users, while Polymarket had resumed operating in the US market shortly before the tournament, foll…