Short-Sale Restrictions and Price Clustering: Evidence from SEC Rule 201

We provide a novel test of information-based theories of price clustering by examining trade, order, and the National Best Bid and Offer (NBBO) quote price clustering during periods when information is removed from the market. We use a natural experiment of short-sale restrictions resulting from Securities and Exchange Commission (SEC) Rule 201 to more effectively determine the impact of information on price clustering. We find evidence of increased price clustering for trades, orders, and NBBO prices during short-sale restrictions. Overall, our findings indicate that short-sale restrictions harm the price discovery process and lead to a reduction in market efficiency.     

Balancing dominance: Diagnosing the buyer-supplier relationship

There is often more than meets the eye in any relationship—especially business relationships. Using the author's “stability matrix” can help you find out just where you stand with your customers or suppliers and where things might be headed.     

Debreu-like properties of utility representations

Traditionally the codomain of a utility function is the set of real numbers. This choice has the advantage of ensuring the existence of a continuous representation but does not allow to represent many preference structures that are relevant to utility theory. Recently, some authors have started a systematic study of utility representations that are not real-valued, introducing the notion of a Debreu chain. We continue their analysis defining two Debreu-like properties, which are connected to a local continuity of a utility representation. The classes of locally Debreu and pointwise Debreu chains here introduced enlarge the class of Debreu chains. We give several examples and analyze some properties of these two classes of chains, with particular attention to lexicographic products.     

Managing disabilities in an integrated health environment: the experience of Aetna

Disability-related outlays are increasing at a rate well above the medical inflation rate. This article discusses the experience of one company in its attempt to manage these skyrocketing costs, by developing a new program that integrates health and related benefits by combining the medical and human resources interventions into a unified program. The authors discuss the initiation, development and progress of the program, concluding with measured results revealing reduced lost work time, improved employee health and productivity, and reduced disability costs.