EVIDENCE FOR RELATIONAL CONTRACTS IN SOVEREIGN BANK LENDING
用工具变量法区分过去还款问题对当前利差的直接影响（价格惩罚）和间接影响（声誉损失），发现惩罚渠道是主要作用机制，为关系合同理论提供了直接证据。
This paper presents direct evidence for relational contracts in sovereign bank lending. Unlike the existing empirical literature, its instrumental variables method allows for distinguishing a direct influence of past repayment problems on current spreads (a “punishment” effect in prices) from an indirect effect through higher expected future default probabilities (“loss of reputation”). Such a punishment provides positive surplus to lenders after a default and decreases the borrower's present discounted value of the net benefits of future borrowing, which create dynamic incentives. Using data on bank loans to developing countries for 1973–1981 and constructing continuous variables for credit history, we find evidence that most of the influence of past repayment problems is through the direct, punishment channel.