This paper argues that it is impossible to achieve the following objectives simultaneously: (i) portfolio diversification, (ii) shareholder representation, and (iii) competition. In an economy where everyone holds the market portfolio, all the companies have the same shareholders. If, in...

We examine the influence of common ownership on commonalities in the information environment. Specifically, we study commonalities in financial statements and in the actions of key agents such as financial analysts and firm managers who contribute and respond to the information environment....

Some scholars have argued that the phenomenon known as common ownership, which refers to an investor's simultaneous ownership of small stockholdings in several competing companies, is anticompetitive and prohibited by the U.S. antitrust laws. These proponents target in particular large...