According to Predictefy data, from May 8 to May 15, Kalshi's weekly notional trading volume reached $4.134 billion, ranking first among prediction markets, approximately 2.13 times the trading volume of Polymarket during the same period. Polymarket's weekly notional trading volume was $1.938 billion, ranking second.
Additionally, Limitless recorded a weekly notional trading volume of $600 million, ranking third; predict.fun had a weekly notional trading volume of $232 million, ranking fourth; and Opinion had a weekly notional trading volume of $207 million, ranking fifth.