Which of the following is true about coinsurance in property insurance?

Coinsurance is a provision found in many property insurance policies that requires the insured to carry a certain percentage of the property's value as insurance in order to receive full reimbursement for a loss. If the insured fails to maintain the required amount of insurance, they may face a penalty at the time of a claim.

The statement that coinsurance does not apply to stated amounts is accurate. In cases where a property has a stated amount (also known as agreed value), the insured and insurer agree on a specific amount of coverage. Since coinsurance is meant to ensure that the insured carries a certain proportion of the property value, it is not applied to these types of situations. In stated amount policies, the agreed value is what the insurer will pay in the event of a total loss, thus negating the necessity for coinsurance calculations.

The other options do not accurately reflect how coinsurance operates within property insurance. Coinsurance is not mandatory for all policies; only some policies, especially standard ones, incorporate this provision. Furthermore, it is relevant to various types of property, not just certain kinds, and it applies to both residential and commercial properties, not exclusively to commercial ones.