We study how political factors shape competition in the mobile telecommunication sector. We show that the way a government designs the rules of the game has an impact on concentration, competition, and prices. Pro-competition regulation reduces prices, but does not hurt quality of services or...

Using new data for the universe of firms covered in Amadeus, we reconstruct the portfolios of shareholders who hold equity stakes in private and publicly-traded European firms. We find great heterogeneity in the degree of portfolio diversification across large shareholders. Exploiting this...

Firm specific information has a damped effect on business group firms' stock prices. Business group affiliated firms' idiosyncratic stock returns are less responsive to idiosyncratic commodity price shocks than are the idiosyncratic returns of otherwise similar unaffiliated firms in the same...

We develop the first comprehensive mapping of the revolving door phenomenon in the U.S. by examining the work experience in executive branch agencies of 1,910,150 individuals covering top corporate positions in 373,011 unique firms. We document that the phenomenon is prevalent, with one out of...