**US sports betting handle reached approximately $166 billion in 2025, an 11% increase from 2024, driven by mobile adoption and state expansions, but 2026 growth has slowed markedly with several months flat or down year-over-year.** Mature markets like New Jersey and Pennsylvania show limited upside, while prediction markets such as Kalshi and Polymarket have captured notable share—especially on NFL and World Cup outcomes—through event contracts that analysts estimate could reach 20%+ of combined volume. The 2026 FIFA World Cup delivered a temporary lift with projected US handle of $2.8–4.3 billion from its expanded 104-match format and home-soil interest. New state launches (Missouri in late 2025) and pending rollouts add incremental volume, but retail betting has collapsed to roughly 1% of total handle. Parlay popularity continues raising blended hold percentages above 10%, though overall handle expansion now hinges on further legalization in large states and sustained operator promotions amid rising competition.