The principle which prevents an insured from receiving a claim that is more than the value of the loss, if the property is insured by more than one company ...

The principle that prevents an insured from receiving a claim that is more than the value of the loss if the property is insured by more than one company is called "contribution". Essentially, this principle ensures that the insured is not overcompensated for their loss by multiple insurers. Under this principle, each insurer will pay a proportionate amount of the loss based on the value of the policy they issued compared to the total value of all policies covering the property. For example, if a property is insured for $100,000 by two different insurance companies, and it sustains a loss of $50,000, each company will pay $25,000 towards the loss.