Dynamics of Markups, Concentration, and Product Spant

• 成果类型: Article
• 署名作者: Helpman, Elhanan; Niswonger, Benjamin
• 署名单位: Harvard University; National Bureau of Economic Research; Centre for Economic Policy Research - UK
• 刊物名称: AMERICAN ECONOMIC JOURNAL-MACROECONOMICS
• ISSN/ISSBN: 1945-7707
• DOI: 10.1257/mac.20200378
• 发表日期: 2022
• 页码: 42-81
• 关键词: market; FIRMS; rise

摘要

We develop a model with a finite number of multiproduct firms together with a continuum of single-product firms and study the dynamics that arise from product innovation. Consistent with the available evidence, the model predicts rising markups and concentration and a declining labor share. Our dynamics predict the possibility of an inverted-U relationship between labor productivity and product span, for which we provide suggestive evidence. In the optimal allocation, product span and labor productivity are strictly positively related. We also characterize optimal policies for these types of sectors.