Predictions marketplace KalshiEX LLC sued the U.S. Commodity Futures Trading Commission on Wednesday, saying the regulator overstepped its bounds when it rejected a proposal to use derivatives contracts to bet on congressional control. In June, Kalshi sought to list contracts that would let users bet on whether a particular party will control the House of Representatives and Senate in a given term. The CFTC banned Kalshi from listing and clearing its cash-settled political event contracts in September, concerned that they would involve unlawful gaming and other activities not in the public's interest.