We show analytically and empirically that the positive abnormal returns from Betting-Against-Beta (BAB) – a beta-neutral portfolio long in low beta stocks and short in high beta stocks – are consistent with market segmentation due to costly information acquisition, as in Merton (1987)....

This paper proposes a model of how biased individuals update beliefs in the presence of informational ambiguity. Individuals are ambiguous about the actual signal-generating process and interpret signals according to the model that can best support their biases. This paper provides a complete...