Fleet drivers have been warned that car thefts peak on a Monday. In addition, white cars are more likely to be stolen than cars of any other colour.
The figures come from analysis of data from the police national computer.
As black is fast becoming the most popular new car colour, the analysis shows that these cars are now the third most likely to be stolen.
Prior to black, silver was the most popular new car colour. However, silver cars are the third least likely car colour to be stolen.
White cars could be more at risk because white is non-metallic and is easier to disguise through re-spraying, suggests the Royal Automobile Club Foundation and Retainagroup, who carried out the research.
The analysis also revealed that, with car theft peaking on Mondays, motorists can relax a little over the weekend as the risk of having their car stolen is one-third less on a Sunday than a Monday.
However, there is some dispute over whether the Monday peak is simply down to the fact that many motorists do not discover their car has been stolen until they get up for work – and that their car may have been stolen over the weekend.
"In the UK, two cars are stolen every minute," said Mark Jones, a director of Retainagroup.
"Prevention is better than cure and we know that visibly marking cars with a unique, recordable and therefore traceable code reduces the chance of theft by more than 50%.
"We're urging more car owners to adopt this strategy to avoid the traumatic experience of having their car stolen, regardless of the colour."