coinsurance

noun | \ ˌkō-in-ˈshu̇r-əns, kō-ˈin-ˌshu̇r- \ | co·in·sur·ance

1. : joint assumption of risk (as by two underwriters) with another

2. : insurance (as fire insurance) in which the insured is obligated to maintain coverage on a risk at a stipulated percentage of its total value or in the event of loss to suffer a penalty in proportion to the deficiency