Polymarket, once the leader in prediction market trading volume, has been overtaken by competitor Kalshi, according to Dune Analytics data. Kalshi's recent funding round has boosted its valuation to $22 billion, surpassing Polymarket's $15 billion valuation following a $600 million investment from Intercontinental Exchange. Polymarket faces significant challenges, including delays in its U.S. market launch, technical issues, and user dissatisfaction over fee changes. The platform's U.S. app remains in testing, with March trading volume only a fraction of Kalshi's. Additionally, Polymarket is under scrutiny from Democratic members of Congress, who have urged the CFTC to intervene due to the platform's controversial betting topics. These challenges have contributed to Polymarket's decline in market dominance.