Long-Run Risk Is the Worst-Case Scenario
研究投资者对经济动态不确定时的资产定价，用非参数方法估计消费过程，并采用悲观模型定价，发现长期风险始终存在，且模型能匹配资产价格、消费和股息的主要事实。
We study an investor who is unsure of the dynamics of the economy. Not only are parameters unknown, but the investor does not even know what order model to estimate. She estimates her consumption process nonparametrically—allowing potentially infinite-order dynamics—and prices assets using a pessimistic model that minimizes lifetime utility subject to a constraint on statistical plausibility. The equilibrium is exactly solvable and the pricing model always includes long-run risks. With risk aversion of 4.7, the model matches major facts about asset prices, consumption, and dividends. The paper provides a novel link between ambiguity aversion and nonparametric estimation.