technology markets and increased rents for small inventors. Is this also true for today's NPEs? Or are they “patent trolls” who … opportunistically litigate over software patents with unpredictable boundaries? Using stock market event studies around patent lawsuit …

The emergence of nonpracticing entities (NPEs) — firms that purchase and hold patent rights but neither innovate … — often disparagingly called “patent trolls” — discourage productive firms from innovating for fear that they will then be … subject to a patent troll suit. Thus, NPEs may discourage innovation, resulting in a social loss …