Chonsei, an exceptional but prevalent housing rental system in the Republic of Korea, functions as private loans between individuals, and its implicit interest rate is called the “chonsei to monthly rent conversion rate”. Although the chonsei to monthly rent conversion rate is much higher than the interest rate of savings accounts or mortgage loans, making chonsei a more expensive channel of financing, chonsei remains a dominant type of rent in Korea. This study provides a novel theoretical model in a continuous-time portfolio selection framework that allows a lessor, given borrowing constraints, to optimally choose between chonsei and monthly rent contracts to show a possible solution to this situation. We investigate the optimal choice between chonsei and the monthly rent of lessors using a rigorous theoretical model and find a closed-form solution to the model. We analyze how credit availability in the banking sector affects the choice problem, showing that the lessor may prefer the chonsei contract over the monthly rent contract, given the borrowing limit from a bank. In addition, we analyze the impact of other major factors, such as the market price of risk, the amount of chonsei deposit, the monthly rental rate, and the income rate, on the lessor’s optimal decision between chonsei and monthly rent.

Chonsei是韩国一种特殊但普遍的住房租赁制度，充当个人之间的私人贷款，其隐含利率称为“Chonsei 到月租金的转换率”。尽管 chonsei 与月租金的转换率远高于储蓄账户或抵押贷款的利率，使得 chonsei 成为更昂贵的融资渠道，但 chonsei 仍然是韩国的主要租金类型。这项研究在连续时间投资组合选择框架中提供了一种新颖的理论模型，允许出租人在给定借款约束的情况下，在 chonsei 和月租合同之间进行最佳选择，以展示针对这种情况的可能解决方案。我们使用严格的理论模型研究了 chonsei 和出租人月租金之间的最优选择，并找到了该模型的封闭式解决方案。我们分析了银行部门的信贷可用性如何影响选择问题，表明考虑到银行的借款限额，出租人可能更喜欢 chonsei 合同而不是月租合同。此外，我们还分析了风险市场价格、房租押金金额、月租率、收入率等其他主要因素对出租人房租与月租最优决策的影响。