In this study, we investigate whether "Chonsei," the distinctive type of housing contract system in Korea, has a favorable impact on house prices during a market downturn. We show the mechanism in which Chonsei prevents a sharp drop in house prices based on sellers' loss aversion behavior. Moreover, using data on the Seoul condominium (i.e., apartment) market during the 2006-2017 period, we find that Chonsei prices have a negative impact on the housing trade volume in a market recession. This finding is consistent with our argument that loss aversion behavior appears with regard to the rise in Chonsei prices and thereby Chonsei functions as a price protector in the Korean housing market.