Asset Price Booms and Macroeconomic Policy: A Risk-Shifting Approach
用风险转移模型分析政策应对资产价格繁荣的效果，发现风险转移导致低效的资产和信贷繁荣，但政策干预无需判断资产是否为泡沫；收紧货币政策和杠杆限制的福利效果模糊，而针对高风险投资的措施更有效。
This paper uses a risk-shifting model to analyze policy responses to asset price booms. We show risk shifting leads to inefficient asset and credit booms in which asset prices can exceed fundamentals. However, the inefficiencies associated with risk shifting arise independently of whether the asset is a bubble. Given evidence of risk shifting, policymakers may not need to determine if assets are bubbles to justify intervention. We then show that some of the main candidate interventions against asset booms have ambiguous welfare implications: tighter monetary policy can mitigate some inefficiencies but at a cost, while leverage restrictions may raise asset prices and lead to more leveraged speculation rather than less. Policy responses are more effective when they disproportionately discourage riskier investments.