What should be the role of a public development bank (PDB)? Which projects/firms should the PDB target? What can theory say about the types of loans and ways of delivering them that PDBs around the world use? We analyze these questions in the context of a model where screening is costly to banks. Underprovision of credit results from the inability of banks to (i) appropriate the full benefits of projects they finance, more pronounced for high value projects; and (ii) internalize the benefits of screening in terms of aggregate lending. PDB intervention naturally addresses inefficiencies originating in failures in the private provision of credit. Though lending to commercial banks at subsidized rates or providing credit guarantees are valid alternatives, guarantees are less effective than subsidies at equivalent cost. PDB lending is particularly important in recessions, when liquidity/capital shortages are likely, and risk profiles deteriorate potentially leading to further credit underprovision. Subsidized lending is further preferred to guarantees when banks are facing a liquidity shortage, while a credit guarantees program has additional benefits when banks are undercapitalized.

中文翻译：

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公共开发银行和信贷市场的缺陷

公共开发银行 (PDB) 应该扮演什么角色？PDB 应该针对哪些项目/公司？关于世界各地的 PDB 使用的贷款类型和提供贷款的方式，理论上可以说些什么？我们在一个模型的背景下分析这些问题，其中筛选对银行来说是昂贵的。信贷供应不足是由于银行无法 (i) 挪用其融资项目的全部收益，对于高价值项目更为明显；(ii) 在总贷款方面内化筛选的好处。PDB 干预自然解决了因私人提供信贷失败而导致的低效率问题。尽管以补贴利率向商业银行提供贷款或提供信用担保是有效的替代方案，但担保不如同等成本的补贴有效。PDB 贷款在经济衰退期间尤为重要，此时流动性/资本可能短缺，风险状况恶化可能导致进一步的信贷拨备不足。当银行面临流动性短缺时，补贴贷款比担保更受欢迎，而当银行资本不足时，信用担保计划有额外的好处。