Stochastic House Appreciation and Optimal Mortgage Lending
在房价和收入随机增长、违约成本高昂且借款人需要激励才能还款的连续时间模型中，刻画了最优抵押贷款合同，发现次贷的许多特征与最优合同一致，且房价下跌时贷款修改对借贷双方都有价值。
We characterize the optimal mortgage contract in a continuous-time setting with stochastic growth in house price and income, costly foreclosure, and a risky borrower who requires incentives to repay his debt. We show that many features of subprime loans can be consistent with properties of the optimal contract and that, when house prices decline, mortgage modification can create value for borrowers and lenders. Our model provides a number of empirical predictions that relate the features of mortgage contracts originated in a housing boom and the extent of their modification in a slump to location and borrowers' characteristics. The Author 2011. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com., Oxford University Press.