For the first four decades of its existence the U.S. nuclear power industry was run by regulated utilities, with most companies owning only one or two reactors. Beginning in the late 1990s electricity markets in many states were deregulated and almost half of the nation's 103 reactors were sold...

We examine whether and to what extent consolidation in the U.S. health insurance industry is leading to higher employer-sponsored insurance premiums. We make use of a proprietary, panel dataset of employer-sponsored healthplans enrolling over 10 million Americans annually between 1998 and 2006...

We thank Lakshmi Aiyar, Shawn Cole, Stijn Claessens, Oded Galor, Adair Morse, Mark Rosenzweig, Jeremy Stein, as well as participants in seminars at the IMF, the NBER Political Economy, Corporate Finance, and Growth Workshops, M.I.T., Northwestern University, the University of Chicago, the WFA...

We study the evolution of profits, investment and market shares in US industries over the past 40 years. During the 1990's, and at low levels of initial concentration, we find evidence of efficient concentration driven by tougher price competition, intangible investment, and increasing...

To what extent do immigrants and the native-born work in separate workplaces? Do worker and firm characteristics explain the degree of workplace concentration? We explore these questions using a matched employer-employee database that extensively covers employers in selected MSAs. We find that...

The 1998 Master Settlement Agreement resolved the unprecedented litigation in which the states sought to recoup the cigarette-related Medicaid costs. The litigation was settled through a combination of negotiated regulatory requirements and financial payments of about $250 billion over 25 years....

Does the mere presence of big banks affect macroeconomic outcomes? In this paper, we develop a theory of granularity (Gabaix, 2011) for the banking sector, introducing Bertrand competition and heterogeneous banks charging variable markups. Using this framework, we show conditions under which...

The recent fall of labor's share of GDP in numerous countries is well-documented, but its causes are poorly understood. We sketch a “superstar firm” model where industries are increasingly characterized by “winner take most” competition, leading a small number of highly profitable (and...

The heavy-tailed distribution of firm sizes first discovered by Zipf (1949) is one of the best established empirical facts in economics. We show that it has strong implications for asset pricing. Due to the concentration of the market portfolio when the distribution of the capitalization of...

Big data on job-vacancy postings reveal several dimensions of the impact of COVID-19 on the U.S. job market. Firms have cut back on postings for high-skill jobs more than for low-skill jobs, with small firms nearly halting their new hiring altogether. New-hiring cuts and downskilling are most...