Prediction Markets' Ad Blitz Escalates Sports Betting Battle as Market Share Hits 16%

Prediction markets Kalshi, Polymarket and Novig are intensifying competition with traditional sportsbooks through celebrity endorsement deals and aggressive advertising, eroding the dominance of DraftKings and FanDuel in the U.S. sports wagering market. Ad spending by prediction markets and major sportsbooks rose 21% in the first seven months of 2026 compared to the same period a year earlier, according to Nielsen data. Traditional sportsbooks' share of legal U.S. sports wagering fell from 76% in 2023 to 64% in the first half of 2026, while prediction markets grew from 1% to 16%, per Sensor Tower. Flutter Entertainment, which owns FanDuel, expects a $270 million hit to adjusted earnings as it invests in its U.S. sportsbook, with CFO Robert Coldrake calling it "an investment in generosity spend." The marketing surge faces legal risk. The U.S. Supreme Court is widely expected to take up whether prediction markets fall under CFTC or state gaming commission jurisdiction.