Coinsurance is the percentage of insurance to the property value. Most companies require that a coinsurance rate of 80% or 90% of the property value be in place at the time of a loss. If this percentage is not met, a coinsurance penalty may result in the event of a claim. For example, if your property is worth $100,000 and the coinsurance requirement is 80%, there would need to be at least $80,000 of coverage in place to pay a claim without incurring a penalty. This penalty could be costly. It is determined by taking the amount of coverage you have and dividing it by the amount of coverage you should have according to the coinsurance requirement. Continuing with the above example, if you have $40,000 of coverage instead of $80,000 (50% of the amount required), the insurance company may penalize you by paying only 50% of your loss.
To avoid a coinsurance penalty, ask your agent for an Agreed Value endorsement on your policy, in addition to insuring your property according to its replacement cost. This endorsement waives any potential coinsurance penalty. There is a small additional cost with most insurance carriers to add this endorsement.