Underinsurance is the quiet defect in commercial insurance. Nothing goes wrong until a claim, and then the policy pays a proportion rather than the loss, because the sums insured said the business was smaller than it is.
How average actually works
Commercial property sections carry a condition of average. If the sum insured is two thirds of the true value, the insurer treats two thirds of the risk as insured and pays two thirds of the claim. The important part is that it applies to partial losses as well as total ones: a business underinsured by a third takes a third off a small escape of water claim too. It is not a penalty for a big loss; it is a permanent discount on every settlement.
The four figures most often wrong
Buildings reinstatement, because it is the cost of rebuilding today including demolition, professional fees and compliance with current regulations rather than the market value or the purchase price. Contents and equipment, because they are insured at replacement as new rather than depreciated book value. Stock, because it moves and peaks. And business interruption gross profit, projected across the indemnity period, which is usually larger than the accounts figure and is where the largest shortfalls sit.
Why it drifts even when nothing changes
Construction cost inflation, longer lead times for materials and plant, higher professional fees, and regulatory requirements that did not apply when a building went up all raise a reinstatement figure without the business doing anything. Index linking on a policy helps and rarely keeps pace on its own. A figure that was right three years ago is usually low now, which is why a periodic professional assessment is worth the cost.
Fixing it, and what to do at renewal
The practical steps are unglamorous: a reinstatement cost assessment for the building, an inventory with current replacement prices for contents and equipment, a stock figure set to the peak or with a seasonal clause, and a gross profit calculation done on the insurance definition over the full indemnity period. Doing that at renewal costs an afternoon and a modest premium increase, which is the cheapest insurance decision available to most businesses.
Questions people ask about underinsurance
What is the condition of average?
Where the sum insured is below the true value, the insurer reduces the claim in the same proportion, and it applies to partial losses as well as total ones.
Should buildings be insured for market value?
No. For the cost of rebuilding today including demolition, professional fees and compliance with current regulations, which is frequently higher than market value.
Does index linking solve underinsurance?
It helps and rarely keeps pace alone. A periodic professional reinstatement assessment is what keeps the figure honest.