The legal answer
Under US federal law, CFTC-regulated prediction markets like Kalshi and Polymarket are classified as commodity derivative exchanges, not gambling operators. They operate as Designated Contract Markets (DCMs) under the Commodity Exchange Act — the same regulatory framework as CME futures.
A federal appeals court reaffirmed this distinction in 2024 when it upheld Kalshi's right to list congressional election contracts over CFTC objections.