Using combinations of weekdays and times of day (before, during, and after trading hours) of earnings announcements, we examine whether managers attempt to strategically time these announcements. We document that the worst earnings news is announced on Friday evening and find robust evidence that only Friday evening announcements represent managers’ rational opportunistic behavior. Friday evening announcements are followed by insider trading in the direction of earnings news and the largest post-earnings announcement drift. Managers also attempt to reduce interaction with investors and hide more than just earnings news by announcing on Friday evening. We find that Friday evening announcements occur later in the evening than announcements on other evenings, firms have a reduced propensity to hold conference calls, and major firm restructuring events are relatively more likely to occur after Friday evening announcements.

We report reduced market response to Friday announcements of dividend changes, seasoned equity offerings, share repurchases, earnings, and mergers, which is seemingly consistent with the notion of investor inattention on Fridays. However, we show that these findings are an outcome of selection bias. Firms that make announcements on Fridays experience reduced market response on any weekday and have common unobserved characteristics across announcement types. After correcting for selection bias, there is no evidence that investors pay less attention to announcements made on Fridays. The method introduced here is applicable to other studies in which an exogenous factor influencing firm performance can actually be associated with firm characteristics.