Many believe intellectual property has overreached, and that policymakers must respond. In this Essay, I argue that the critique may have merit, but private parties are in some cases taking matters into their own hands. Firms and individuals are increasingly injecting information into the public domain with the explicit goal of preempting or undermining the potential property rights of economic adversaries. Biotechnology firms invest millions of dollars in public domain gene sequence databases, to prevent hold-ups by firms with patents on short gene sequences. Major software firms fight entrenched rivals by investing millions of dollars, contributing to open source operating systems. In both cases, property-preempting investments (PPIs) are...