Economics Insights @ CBS

This paper examines the so far unexplored relationship between short selling and news. It starts with a theoretical analysis of short selling's potentially beneficial and harmful effects, a brief history of its regulation and a review of the existing empirical literature. The study that follows uses daily NYSE short sale trading data representing a total of 2.3 million firm days and a measure negativity of firm news based on a content analysis of the Dow Jones Newswires.

We test if cooperation is promoted by rank-order competition between groups in which all groups can be ranked first, i.e., when everyone can be a winner. This type of rank-order competition has the advantage that it can eliminate the negative externality a group's performance imposes on other groups. However, it has the disadvantage that incentives to outperform others are absent, and therefore it does not eliminate equilibria where all groups cooperate at an equal but low level.

Infinitely repeated games is the pre-dominant paradigm within which economists study long-term strategic interaction. The standard framework allows players to condition their strategies on all past actions; that is, assumes that they have unbounded memory. That is clearly a convenient simplification that is at odds with reality. In this paper we restrict attention to one-period memory and characterize all totally mixed equilibria. In particular, we focus on strongly mixed equilibria. We provide conditions that are necessary and sufficient for a game to have such an equilibrium.