Why Beta is still such a popular measure even though the evidence suggests that CAPM does not work very well to predict security's returns? a. Beta is very easy to apply and investors do not want to spend too much time and effort on security analysis b. Security returns don't matter to the investors, investors only care about risk measures For a large well-diversified portfolio that most investors hold Beta becomes a good approximator of the total risk (and firm specific part of the risk becomes negligible) d. Beta is not a popular measure and most investors don't use it c.