Say stocks of firms which change their logo in a given year tend to outperform (have higher abnormal returns the stocks of firms which don't change their logos for the following year. If markets are efficient and you used the correct model for expected returns in your analysis, what must be true about firms that change their logos relative to firms that don't change their logos? Firms that change their logos are more exposed to risk than firms that don't change their logos. Firms that change their logos are equally exposed to risk as firms that don't change their logos. Firms that change their logos are less exposed to risk than firms that don't change their logos. We can't make any of the above statements