In this article, we examine the effect of the imperfect mobility of goods on international risk sharing and, through that, on the investment in risky projects, welfare and growth. We find that the welfare gain of financial market openness is not monotonic with respect to investors' risk aversion...

Many industries are geographically concentrated. Many mechanisms that could account for such agglomeration have been proposed. We note that these theories make different predictions about which pairs of industries should be coagglomerated. We discuss the measurement of coagglomeration and use...

This paper studies localization of academic and industrial knowledge spillovers. Using data on U.S. Research and Development laboratories, that quantify spatial aspects of learning about universities and firms as well as their locations, I find that academic spillovers are more localized than...

The returns to face-to-face interactions are of central importance to understanding the determinants of agglomeration. However, the existing literature studying patterns of geographic proximity in patent citations or industrial co-location has struggled to disentangle the benefits of...

People continue to live in many big American cities, because in those cities housing costs less than new construction. While cities may lose their productive edge, their houses remain and population falls only when housing depreciates. This paper presents a simple durable housing model of urban...

Crime rates are much higher in big cities than in either small cities or rural areas, and this situation has been relatively pervasive for several centuries. This paper attempts to explain this connection by using victimization data, evidence from the NLSY on criminal behavior and the Uniform...

Should China build mega-cities or a network of linked middle-sized metropolises? Can Europe's mid-sized cities compete with global agglomeration by forging stronger inter-urban links? This paper examines these questions within a model of recombinant growth and endogenous local amenities. Three...

Diversified firms have different values than comparable portfolios of single-segment firms. These value differences must be due to differences in either future cash flows or future returns. Expected security returns on diversified firms vary systematically with relative value. Discount firms...

Investor sophistication has lagged behind the growing complexity of retail financial markets. To explore this, we develop a dynamic model to study the interaction between obfuscation and investor sophistication. Taking into account different learning mechanisms within the investor population, we...