A new study of Polymarket’s five-minute Bitcoin contracts identified concentrated spot orders during the final seconds before settlement, followed by rapid price reversals once the contracts expired. David Dai and Ruizhe Jia of Stanford University and Shihao Yu of Singapore Management University analyzed more than 60 million Polymarket fills alongside tick-level Bitcoin trades and order-book data from Binance. Their sample ran from July 1, 2025, through April 8, 2026, covering the periods before and after the five-minute contracts began trading on February 12.