The increasing popularity of non-dealer security markets that offer automated, computer-based, continuous trading reflects the conventional wisdom that such markets are more efficient for all issues, large and small. This article uses a recent testing methodology to estimate the relative...

Margin requirements are designed to control the default risk inherent to commitments undertaken by traders writing options. Much like similar institutions, the Tel Aviv Stock Exchange first adopted a system based on the Standard Portfolio Analysis of Risk (SPAN), which sets required levels of...