Factors contributing to underinsurance
The property in question had been left vacant and the owner failed to adjust its insured value over the years. At the time of the storm damage, the property was insured for just $1 million, a fraction of its current estimated replacement cost of $4,460,000, as confirmed by a quantity surveyor in an independent valuation report.
The owner commissioned a reinstatement valuation to determine the cost of repairing their damaged property. The report established the repair cost at $461,000, with $21,500 of that amount allocated to removal of debris, which was covered as a benefit under the insurance policy and immediately paid in full by the insurer.
After subtracting the removal of debris cost, the repair bill amounted to $439,500. However, because the property owner was underinsured, their claim payment was subject to the co-insurance clause under the terms of their insurance policy. The insured value of the property was only a quarter of its estimated replacement cost, leaving the property owner with a significant underinsurance gap.
How the incremental effect of underinsurance cascades in a claim
The co-insurance clause in property insurance policies stipulates that the insured party must carry insurance coverage that meets a specified percentage of the property's total current value. Failure to meet this requirement results in t he insurer only paying out a percentage of the claim, proportional to the percentage of the property's value that was insured.
In this case, the property owner's insurance policy allowed for a variation of insured value to actual property value of 80%, but the insured property value was only about 25% of its actual current value.
The insurer will use the following formula under the co-insurance clause to reduce the amount it will pay for a loss. They do this to protect themselves against clients who intentionally devalue their property or assets in order to pay less premium.

Using this formula, the property owners insurance claim payment was calculated as follows:
Insured Value of the property |
$1,000,000 |
Current Value of the property |
$4,460,000 |
Co-insurance Provision: |
80% |
Loss Amount |
$439,500 |
The application of the co-insurance clause effectively reduced the claim payment to just $123,178 from repair costs of $439,500.