Implications of a reduction in tick size on short-sell order execution

The U.S. Securities and Exchange Commission is committed to having exchanges fully implement decimal pricing by April 9, 2001, and is also considering revising the Uptick Rule. We consider the likely impact of the pending smaller tick size associated with decimalization on the efficacy of this rule by examining the execution quality of NYSE short-sell orders immediately before and after the tick size was reduced from 1/8th to 1/16th in 1997. We conclude that, in general, short market orders will receive better execution after decimalization, but at-the-quote limit orders will receive worse execution, and suggest revisions to the Rule.