I propose a theoretical model of a debt contract between a sovereign and its international lenders that determines the optimal debt maturity structure and related costs. It is shaped by two financial frictions: limited liability (the country cannot guarantee that it will not dilute its obligations or default on them) and market incompleteness. In equilibrium, debt dilution constrains the amount of long-term debt issuance. I use this framework to evaluate the impact of two policy interventions: the possibility of sovereign debt restructuring with private creditors and international official lending in the event of exclusion from the international capital markets. The possibility of restructuring after default stimulates long-term debt issuance; however, in equilibrium, those tools are unable to loosen the constraint on long-term debt issuance. Consistently with the empirical literature, I find that even when these policy options are available, the country tends to issue mainly short-term debt.

我提出了一个主权国家与其国际贷款人之间的债务合同理论模型，该模型确定了最佳债务期限结构和相关成本。它是由两种金融摩擦造成的：有限责任（国家不能保证不会稀释其义务或不违约）和市场不完整性。在均衡状态下，债务稀释限制了长期债务的发行量。我使用这个框架来评估两种政策干预的影响：与私人债权人进行主权债务重组的可能性以及在被排除在国际资本市场之外的情况下国际官方贷款的可能性。违约后重组的可能性刺激长期债务发行；然而，在均衡状态下，这些工具无法放松对长期债务发行的限制。与实证文献一致，我发现即使有这些政策选择，该国也倾向于主要发行短期债务。