A New Look at the Monday Effect

It is well documented that expected stock returns vary with the day-of-the-week (the Monday or weekend effect). In this article we show that the well-known Monday effect occurs primarily in the last two weeks (fourth and fifth weeks) of the month. In addition, the mean Monday return of the first three weeks of the month is not significantly different from zero. This result holds for most of the subperiods during the 1962–1993 sampling period and for various stock return indexes. The monthly effect reported by Ariel (1987) and Lakonishok and Smidt (1988) cannot fully explain this phenomenon.     

The Effects of Regulating Hidden Add‐On Costs

We examine the welfare effects of price and disclosure regulation in a model where firms can shroud add‐on costs, such as penalty fees for consumer financial products. Such regulation can increase or decrease welfare even when there are no direct costs. There are, however, strong complementarities between price controls and disclosure mandates: conditional on disclosure being mandated, price controls always (weakly) increase welfare, and conditional on prices being sufficiently constrained, disclosure mandates always (weakly) increase welfare.     

THE EXPECTED NUMBER OF COOPERATORS IN THE N‐PERSON PRISONERS’ DILEMMA WITH RANDOM ORDER MOVES*

The present paper examines the possibility of cooperation occurring in the N‐person prisoners’ dilemma, played with randomly ordered moves and imperfect information. To take into account imperfect cooperation, the degree of cooperation is evaluated in terms of the expected number of cooperators. It is shown that: (i) the expected number of cooperators is maximized at an equilibrium, a combination of strategies each of which is a type of trigger strategy; (ii) the maximum expected number of cooperators is attained in a state of imperfect cooperation for a range of payoff functions; and (iii) the maximum expected number of cooperators is non‐decreasing when the size of players’ group increases.