The Swede was driving a Mercedes SLS AMG - which has a top speed of 317km/h
A Swedish motorist caught driving at 290km/h (180mph) in Switzerland could be given a world-record speeding fine of SFr1.08m ($1m; £656,000), prosecutors say.
The 37-year-old, who has not been named, was clocked driving his Mercedes sports car at 170km/h over the limit.
Under Swiss law, the level of fine is determined by the wealth of the driver and the speed recorded.
In January, a Swiss driver was fined $290,000 - the current world record.
Local police spokesman Benoit Dumas said of the latest case that "nothing can justify a speed of 290km/h".
"It is not controllable. It must have taken 500m to stop," he said.
The Swede's car - a Mercedes SLS AMG - has been impounded and in principle he could be forced to pay a daily fine of SFr3,600 for 300 days.