CRIME against small businesses cost firms at least £721m last year.
New research shows the scale of crimes that include theft, damage, arson and other attacks.
The number of crime- related business insurance claims rose 27% in the last three months of 2005 compared with the previous quarter, says the study by AXA insurers.
AXA said it thought the true cost of business crime was much higher, because companies did not claim for many offences.
One in five of all insurance claims by small and medium-sized firms last year was crime-related.
An AXA spokesman said: "These findings demonstrate just how much of a problem crime is for small and medium- sized businesses.
"Crime accounts for one-fifth of our entire claim book.
"While most are low- level, inexpensive crimes, such as petty theft and malicious damage, some claims run into tens of thousands of pounds and can put enterprises out of business."
Derby topped the business crime league, followed by Bradford, Nottingham, Cardiff, Middlesbrough and Liverpool, said the report.