Competition across space can be fundamentally altered by changes in market institutions. We propose a framework that integrates market-altering policy changes in the spatial analysis of competitive behavior and incorporates endogenous breaks in explanatory variables for spatial panel datasets. This paper fills a gap in the literature between work focusing on spatial price responsiveness of agents and work on changes in market regulations that affect competition. We apply the framework to an important current fishery management policy to explore how a change from aggregate to individual fishing quotas affects the spatial price responsiveness of fish processors. Copyright © 2012 John Wiley & Sons, Ltd.