We show that the stock market downturns of 2000–2002 and 2007–2009 have very different proximate causes. The early 2000s saw a large increase in the discount rates applied to profits by rational investors, while the late 2000s saw a decrease in rational expectations of future profits. We reach these conclusions by using a VAR model of aggregate stock returns and valuations, estimated both without restrictions and imposing the cross-sectional restrictions of the intertemporal capital asset pricing model (ICAPM). Our findings imply that the 2007–2009 downturn was particularly serious for rational long-term investors, whose losses were not offset by improving stock return forecasts as in the previous recession. (JEL G12, N22)