The US Commodity Futures Trading Commission (CFTC) is investigating Polymarket, a prominent crypto prediction market, over allegations of insider trading involving $800 million in oil-related bets. The inquiry focuses on whether traders with advance knowledge of US military actions exploited this information to make profitable bets on oil price movements. This investigation could have significant implications for the legality of onchain prediction markets, particularly if they are deemed to resemble event-based swaps or binary options, which fall under CFTC jurisdiction. Polymarket has faced regulatory scrutiny before, having been fined $1.4 million by the CFTC in January 2022 for operating an unregistered event-based swap facility. Despite efforts to geofence US users, the substantial volume of oil-market activity suggests potential breaches. The outcome of this investigation could lead to stricter compliance requirements, including enhanced KYC protocols and more robust geo-fencing measures. The broader prediction market sector may face reclassification challenges if geopolitical event markets are deemed illegal derivatives.