The Private Costs of Patent Litigation

This paper estimates the total cost of patent litigation. We use a large sample of stock market event studies around the date of lawsuit filings for US public firms from 1984-99. Even though most lawsuits settle, we find that the total costs of lawsuits are large compared to estimated legal fees, estimates of patent value, and R&D spending. By the late 1990s, alleged infringers bore expected costs of over $16 billion per year. These estimates support the view that infringement risk should be a major concern of policy.