This survey examines recent developments in economic research relating to antitrust, paying specific attention to research in the areas of collusion and merger enforcement. Research relating to both collusion and mergers has made significant advances in the last twenty years. With respect to...

Concentration-based screens for horizontal mergers, such as those employed in the US DOJ and FTC Horizontal Merger Guidelines, play a central role in merger analysis. However, the basis for these screens, in both form and level, remains unclear. We show that there is both a theoretical and an...

Overconfident CEOs over-estimate their ability to generate returns. Thus, on the margin, they undertake mergers that destroy value. They also perceive outside finance to be over-priced. We classify CEOs as overconfident when, despite their under-diversification, they hold options on company...

We analyze private fixed investment in the U.S. over the past 30 years. We show that investment is weak relative to measures of profitability and valuation - particularly Tobin's Q, and that this weakness starts in the early 2000's. There are two broad categories of explanations: theories that...

Using patents as indicators of inventive activity, this article characterizes the concentration of origins of invention from 1976 to 2010, and how these changed over time. The analysis finds pervasive deconcentration in virtually every area related to ICT, but it can explain only a small part of...

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...

Both individual experiences and community characteristics influence how much people trust each other. Using data drawn from US localities we find that the strongest factors that reduce trust are: i) a recent history of traumatic experiences, even though the passage of time reduces this effect...

Using a sample of Harvard undergraduates, we analyze trust and social capital in two experiments. Trusting behavior and trustworthiness rise with social connection; differences in race and nationality reduce the level of trustworthiness. Certain individuals appear to be persistently more...

We provide a new explanation to the limited stock market participation puzzle. In deciding whether to buy stocks, investors factor in the risk of being cheated. The perception of this risk is a function not only of the objective characteristics of the stock, but also of the subjective...

Are individuals who trust others better off than those who do not? Do trustworthy people prosper more than untrustworthy ones? We first pose these questions in a search model where individuals face repeated choices between trusting (initiating an investment transaction) and not trusting, and...