We study how to design an optimal government loan program for risky R&D projects with positive externalities. With adverse selection, the optimal government contract involves a high interest rate but nearly zero cofinancing by the entrepreneur. This contrasts sharply with observed loan schemes. With adverse selection and moral hazard, allowing for two levels of effort by the entrepreneur, the optimal policy consists of a menu of at most two contracts, one with high interest and zero self-financing and a second with a lower interest plus cofinancing. Calibrated simulations assess welfare gains from the optimal policy, observed loan programs, and a direct subsidy to private venture capital firms. The gains vary with the size of the externalities, the cost of public funds, and the effectiveness of the private venture capital industry. (JEL D82, D86, G24, L26, O31, G32, H81)

中文翻译：

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政府资助研发：一种机制设计方法

我们研究如何为具有正外部性的高风险研发项目设计最优的政府贷款计划。通过逆向选择，最优的政府合同涉及高利率，但企业家的联合融资几乎为零。这与观察到的贷款计划形成鲜明对比。由于逆向选择和道德风险，允许企业家进行两个级别的努力，最优政策由最多两个合同组成的菜单，一个具有高利率和零自筹资金，另一个具有较低利率和联合融资。校准后的模拟评估了最优政策、观察到的贷款计划以及对私人风险投资公司的直接补贴带来的福利收益。收益随外部性的大小、公共资金的成本和私人风险投资行业的有效性而变化。（JEL D82，