Patent Trolls and the Market for Acquisitions
研究了州反专利流氓法对小型企业收购的影响，发现法律实施后收购数量下降、收购价格上升，大企业转而增加内部研发。
Abstract I study the effect of patent-infringement claims by patent trolls on acquisitions of small firms. Exploiting staggered adoption of state anti-patent troll laws, I find that the laws have two effects. First, the number of acquisitions of small firms declines after these laws are adopted. Second, the anti-troll laws increase the acquisition price for acquirers. The market reflects the increased cost of acquisition as measured by lower acquisition announcement returns. Large firms increase R&D after the adoption of state laws, replacing external innovation. Using a sample of acquisitions that are plausibly unaffected by the laws, I disentangle alternative explanations.