We develop a model of repeated microcredit lending to study how group size affects optimal group-lending contracts with joint liability. In the setting being studied, a benevolent lender provides microcredit to a group of borrowers to invest in projects. The outcome of each risky project is not observable by the lender; therefore, if some of the borrowers default on their loan repayments, the lender cannot identify strategic default. The group will be entitled to a subsequent loan if total loan obligation is met. We characterize the optimal contract and determine the optimal size of the borrowers’ group endogenously. We find that although joint liability contracts are feasible under a smaller set of parameter values than individual liability contracts, joint liability has positive effects on the borrowers’ repayment amount and welfare. Our analysis also suggests that group size should increase with project risk. Furthermore, we analyze the effects of partial joint liability, less severe punishment, and pr...

中文翻译：

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连带责任合同中的最佳团体人数

我们建立了一个重复的小额信贷模型，以研究群体规模如何影响具有连带责任的最优群体贷款合同。在所研究的环境中，仁慈的贷方向一组借款人提供小额信贷，以投资项目。贷方无法观察到每个风险项目的结果；因此，如果某些借款人没有偿还贷款，则贷方无法确定战略性拖欠。如果满足总贷款义务，则该集团将有权获得后续贷款。我们表征最优合同，并内生确定借款人集团的最优规模。我们发现，虽然连带责任合同在参数值集小于单个责任合同的情况下是可行的，但连带责任对借款人的还款额和福利产生积极影响。我们的分析还表明，团队规模应随着项目风险而增加。此外，我们分析了部分连带责任，较轻的处罚和公害的影响。