© 2020, © 2020 Taylor & Francis Group, LLC. This article assesses the influence of Private Security Companies¿ (PSCs¿) violence against insurgents and noncombatants on the frequency of insurgent attacks against PSCs during the 2004 to 2009 period of the Iraq War. It finds that PSC violence may have exerted fairly weak influence on short-term variations in the frequency with which insurgents attacked the firms. It also finds that variations in the frequency of insurgent attacks against PSCs may have been at least partly a side-effect of variations in the overall frequency of insurgent violence in Iraq that were, in turn, driven by events that were beyond the firms¿ control.