Ozcan, YasinGreenstein, Shane2020-06-262020-04Ozcan, Yasin, and Shane Greenstein. "Technological Leadership (de)Concentration: Causes in Information and Communication Technology Equipment." Industrial and Corporate Change 29, no. 2 (April 2020): 241–263.0960-6491http://nrs.harvard.edu/urn-3:HUL.InstRepos:42675342Using patent data from 1976 to 2010 as indicators of inventive activity, we determine the concentration level of where inventive ideas originate and then examine how and why those concentrations change over time. The analysis finds pervasive deconcentration in every area related to the Information and Communication Technology equipment market. We find that booms and busts play an important role in deconcentration trends. In comparison, new entry explains surprisingly little and merger and acquisition activity does not revert the trend.en-USEconomics and EconometricsJournal Article2020-06-2610.1093/icc/dtz056