Sixteen bets made $100,000 accurately predicting the timing of the US airstrikes against Iran on 27 February. Later, a single user would make over $550,000 after betting that Ayatollah Ali Khamenei would topple, just moments before his assassination by Israeli forces. On 7 April, right before Donald Trump announced a temporary ceasefire with Iran, traders bet $950m that oil prices would come down. They did.

These bets and other well-timed wagers accurately predicted the precise timing of major developments in the US-Israel war with Iran, creating huge windfalls and raising concerns among lawmakers and experts over potential insider trading.

Betting – once largely siloed to sporting events – has now spread to include contracts on news events where insider information could give some traders an advantage.

The proliferation of online betting markets like Polymarket and Kalshi has allowed bets on virtually any news event. It’s also easier than ever to buy commodity derivatives like oil futures, where traders gamble on what the price of oil will be in the future.

Leaders of some US federal agencies and some members of Congress said they want to crack down on suspicious trading taking place across different marketplaces, but it’s unclear how much leeway regulators will make.

“Is the problem that we don’t have legislation or that we don’t have enforcement capabilities?” said Joshua Mitts, a law professor at Columbia University. “To have a law that can’t really be enforced effectively given the technological limitations, it’s sort of putting the cart before the horse.”