Bubbles and Crises
解释银行代理关系如何导致资产泡沫，泡沫破裂后引发违约和金融危机，并指出风险可来自实体或金融部门，金融脆弱性源于信贷扩张不足。
In recent financial crises a bubble, in which asset prices rise, is followed by a collapse and widespread default. Bubbles are caused by agency relationships in the banking sector. Investors use money borrowed from banks to invest in risky assets, which are relatively attractive because investors can avoid losses in low payoff states by defaulting on the loan. This risk shifting leads investors to bid up the asset prices. Risk can originate in both the real and financial sectors. Financial fragility occurs when positive credit expansion is insufficient to prevent a crisis.