Broadly Decreasing Risk Aversion
研究存在两个加性风险源时的决策问题，提出“广义递减风险厌恶”条件，推导出效用函数必须为线性加指数形式，并证明该条件对投资组合和风险规避企业的比较静态分析至关重要。
This paper considers decision-making in the presence of two additive risk sources, with no restrictions on the relation between the two risks. A utility function is said to exhibit broad DARA if and only if a rise in wealth always decreases the magnitude of the risk premium for one of the risks vis-a-vis the other. A condition on utility functions giving this property is derived: utility must be of the linear plus exponential form. It is shown that certain problems involving portfolios and risk-averse firms give unambiguous comparative statics if and only if utility exhibits broad DARA.