correlated assets. As investors shift attention from firms towards systematic risk factors, stock prices become less informative …, increasing systematic uncertainty and incentivizing learning about the systematic risk. This learning complementarity leads to … risk concentration …

decision theory to characterize when learning or discriminating among competing probability models is challenging. I also use … choice theory under uncertainty to explore the ramifications of model uncertainty and learning in environments in which … underpinnings of asset pricing models. I illustrate how statistical ambiguity can alter the risk-return tradeoff familiar from asset …

macroeconomic variables. However, the presence of time-varying risk premia requires an adjustment of market prices to obtain the … estimating risk premia and highlights the proliferation of risk pricing factors that result in a wide range of different asset …-price-based expectation measures. It then describes a key methodological innovation to evaluate the empirical plausibility of risk premium …