Kalshi has emerged as the leading prediction market platform, achieving a weekly notional trading volume of $4.134 billion from May 8 to May 15, according to Predictefy data. This volume is approximately 2.13 times greater than that of its closest competitor, Polymarket, which recorded $1.938 billion in the same period. Other notable platforms include Limitless, which ranked third with a weekly volume of $600 million, predict.fun with $232 million, and Opinion with $207 million. These figures highlight Kalshi's dominant position in the prediction market sector.