The Patent Litigation Explosion

This Article provides the first look at patent litigation hazards for public firms during the 1980s and 1990s. Litigation is more likely when prospective plaintiffs acquire more patents, when firms are larger and technologically close and when prospective defendants spend more on research and development (“R&D”). The latter suggests inadvertent infringement may be more important than piracy. Public firms face dramatically increased hazards of litigation as plaintiffs and even more rapidly increasing hazards as defendants, especially for small public firms.

The increase cannot be explained by patenting rates, R&D, firm value or industry composition. Legal changes are the most likely explanation.