When Is an Outcome Decided? Pricing Near-Certain Bets in Live Sports Markets

Abstract

Prediction markets let people trade on the result of a sports game while it is being played. Late in a game, the contract on the team with a big lead, which pays one dollar if that team wins, often trades a few cents below a dollar. A 2026 study of 23 million in-game trades found that in the final ten minutes, contracts near one dollar paid off more often than their prices implied. We present a system that tests whether that discount can be collected safely. Drawing on thousands of games and many different strategies, we found that our best rules, traded live, earned 4.15% per position after fees. Finally, we discuss where the research goes next.