Kalshi, Polymarket and other prediction market platforms have filed a lawsuit against Kentucky over its 14.25% transaction tax on event contracts, marking the first legal challenge to a state-level tax specifically targeting the prediction market industry. The lawsuit names several major platforms as plaintiffs, including Kalshi, Polymarket and Crypto.com, according to a report from PredictionNews. The platforms are seeking to block enforcement of the tax, which was enacted as part of a broader omnibus bill in the Kentucky legislature.