Minnesota became the first US state to ban prediction markets, in a move that widens the row over the platforms. The White House is suing to overturn the ban.

The markets were launched with high-minded ambitions of using the wisdom of the crowd to forecast future events, and help business leaders and politicians make better decisions. But they have been hit by insider-trading scandals, notably involving US military action in Venezuela and Iran.

The companies have a major incentive to prevent insider trading, Semafor’s business editor wrote: Polymarket is more valuable as a tool to help big firms hedge investment risk than it is as a bookmaker for “US black-op nighttime raids.”