Storms and floods late last year failed to trigger reinsurance programmes because the Lloyd's claims office (LCO) identified the poor weather as two separate events.
The LCO identified the storms lasting from October 29 to November 4 as category OOF and the storms from November 5 to 11 as OOJ. Insurers have already estimated the storms will cost them around £500m.
A Lloyd's spokesman said identifying the storms as one event may have exposed some reinsurers.
“The Lloyd's claims office identified two events and issued category codes at the request of the non-marine market because, at the time, they thought there had been significant losses and they thought reinsurance programmes would be activated,” he said.
However, the spokesman said losses were lower than anticipated and even further storms over the festive period did not trigger reinsurance programmes.
Guy Carpenter's catastrophe services division Instrat UK has released a report into the effects of the flooding on insurers in which it identified a number of issues and possible responses.
It said insurers could find it difficult to increase premiums because they were under competitive and regulatory restraints, and because they did not always have sufficient information on future risk levels in their claims databases.
It said insurers could transfer risk to the wider financial markets and practise limitation by capping payouts or increasing excesses.
The report said using preventative measures for loss control had potential, as had mitigation measures on older properties.
And it suggested a government scheme to cover uninsurable risks.
The Association of British Insurers has already said that its members could not be expected to maintain flood cover under particular conditions, such as that of a floodplain development taken against the advice of the Environment Agency.
It also warned that cover may not be available to new developments without adequate flood defences, properties for which residents declined flood defences on aesthetic grounds and properties bought cheaply because of their increased flooding risks.