A failed US insider trading case against Mark Cuban, the billionaire entrepreneur, could open up a division in the way the US and UK authorities enforce the rules against market abuse, leaving the rules much stricter in the UK.
The US Securities and Exchange Commission last week raised the stakes by taking it up on appeal. If the SEC loses again and the case becomes a guiding precedent, US authorities could find it much harder to prevent a form of trading on non-public information that is punished routinely in the UK.
