Effects of Corporate Diversification on Productivity
利用工厂级数据发现，多元化企业在某一时点生产率更高，但动态来看，企业多元化后净生产率下降，且股票价格与生产率的关系在多元化和单一企业间同样紧密。
Using plant‐level observations from the Longitudinal Research Database I show that conglomerates are more productive than stand‐alone firms at a given point in time. Dynamically, however, firms that diversify experience a net reduction in productivity. While the acquired plants increase productivity, incumbent plants suffer. Moreover, stock prices track firm productivity and this tracking is equally strong for diversified and stand‐alone firms. Therefore, lower transparency of conglomerates is unlikely to explain the discrepancy between productivity and stock prices on average. Finally, I offer some evidence that this discrepancy may arise because conglomerates dissipate rents in the form of higher wages.