Patent Portfolio Management of Sequential Inventions: Evidence from US Patent Renewal Data

This paper investigates a firm's decisions regarding renewal and patenting of sequential inventions and tests the implications of a dynamic model of patent portfolio management where a firm makes the decisions taking into account complementarity and substitutability across sequential inventions. We use cross-price effects of renewal fees and filing fees on renewal and patenting decisions to identify complementarity or substitutability. We find that higher filing fees are associated with a lower probability of patent renewal, which supports the idea of complementarity across sequential inventions.