Pastor, LubosStambaugh, Robert F2023-05-222023-05-2219992016-06-15https://repository.upenn.edu/handle/20.500.14332/34380Costs of equity for individual firms are estimated in a Bayesian framework using several factor-based pricing models. Substantial prior uncertainty about mispricing often produces an estimated cost of equity close to that obtained with mispricing precluded, even for a stock whose average return departs significantly from the pricing model's prediction. Uncertainty about which pricing model to use is less important, on average, than within-model parameter uncertainty. In the absence of mispricing uncertainty, uncertainty about factor premiums is generally the largest source of overall uncertainty about a firm's cost of equity, although uncertainty about betas is nearly as important.This is the peer reviewed version of the following article, which has been published in final form at http://dx.doi.org/10.1111/0022-1082.00099. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.FinanceFinance and Financial ManagementArticle