Weekly trading volume on Polymarket and Kalshi has fallen as demand cooled in the absence of major sports and political events. Dune Analytics data cited by Bloomberg showed combined volume across Polymarket's global and U.S.-only platforms was down 56% by the end of last month from the record high reached in June, while Kalshi's weekly volume declined about 25% over the same period after the World Cup ended. Polymarket had previously drawn heavy activity from World Cup-related wagers, underscoring how prediction markets tend to expand around headline events and then soften when catalysts fade.