LAUSR

Compulsory licensing allows governments to license patented inventions without the consent of patent owners. Intended to mitigate the potential welfare losses from enforcing foreign-owned patents, many developing countries use this policy to improve access to drugs that are covered by foreign-owned patents. The effects of compulsory licensing on access to new drugs, however, are theoretically ambiguous: Compulsory licensing may encourage innovation by increasing competition or discourage innovation by reducing expected returns to R&D. Empirical evidence is rare, primarily because contemporary settings offer little exogenous variation in compulsory licensing. We address this empirical challenge by exploiting an event of compulsory licensing as a result of World War I when the US Trading with the Enemy Act made all German-owned patents available for licensing to US firms. Firm-level data on German patents indicate that compulsory licensing was associated with a 30 percent increase in invention by German firms whose inventions were licensed.