Patent quality, firm value, and investor underreaction: Evidence from patent examiner busyness

This paper attempts to study the causal effect of examiner busyness on patent quality and firm value. Using a broad set of patent quality measures, we find strong evidence that patents allowed by busy examiners exhibit significantly lower quality. Further, examiner busyness of firms’ patents negatively predicts the firms’ future stock returns, which is consistent with investor underreaction to examiner busyness. Examiners’ experience helps attenuate the negative effect of examiner busyness.