中文摘要
私人主体不会将自身投资决策对主权债券价格及违约风险的影响内部化。因此,标准的外部性论证意味着投资不足,且若以非扭曲性方式融资,补贴可以改善福利。我们将这一逻辑与一种反向力量相对照。当主权政府相对于家庭缺乏耐心时——这很可能源于政治经济学因素——其会认为自由放任下的资本积累过度,并可能更倾向于对其征税。我们将这两种机制嵌入一个主权违约模型,该模型包含分散化的资本投资、长期公共债务与随机趋势增长,并根据西班牙经济的显著特征进行校准。我们发现,从数量上看,缺乏耐心渠道占据主导,以致基于家庭福利,自由放任优于政府的理想财政政策。
Abstract
Private agents do not internalize the impact of their investment decisions on the sovereign’s bond prices and default risk. Therefore, a standard externality argument implies that investment is insufficient and that a subsidy can improve welfare, if financed by non-distortionary means. We contrast this logic with a countervailing force. When the sovereign is impatient relative to households, plausibly due to political economy factors, it finds laissez-faire capital accumulation excessive and might prefer instead to tax it. We embed both mechanisms in a sovereign default model with decentralized capital investment, long-term public debt, and stochastic trend growth, calibrated to salient features of the Spanish economy. We find that the impatience channel dominates quantitatively, to such an extent that laissez-faire is preferable to the government’s ideal fiscal policy, based on households’ welfare.