We examine how market power in the run-up to the 2007–2009 crisis affected banks’ systemic risk during the crisis, and whether this effect was influenced by two key factors: securitization and bank capital. Using a sample of the largest listed banks from 15 countries, we find that more market power prior to the crisis is connected to larger levels of realized systemic risk during the crisis. The use of securitization exacerbated the effect of market power on systemic risk, while capitalization partially mitigated it.