Optimal vs. Traditional Securities under Moral Hazard
解释了为何成熟企业广泛使用传统证券（如股权、债务、认股权证），尽管标准模型认为它们几乎不是最优融资工具，但实际中这些证券能接近最优效果。
This paper provides an explanation for the widespread use of traditional securities by wellestablished firms. Standard moral hazard models predict that equity, debt, and warrants are almost never optimal financing instruments. I show that issuing these securities is, nevertheless, nearly optimal: the issuer would gain very little by using non-traditional securities instead. Combined with equity, one debt issue (without multiple layers of seniority) and one warrant issue (without multiple exercise prices) suffice to achieve near optimality. The near optimality of traditional financing depends crucially on the issuer's ability to use war? rants in addition to debt and equity.