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Abstract:
Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a general equilibrium theory of economic growth in an urban environment. In our theory, variation in the urban structure through the growth, birth, and death of cities is the margin that eliminates local increasing returns to yield constant returns to scale in the aggregate. We show that, consistent with the data, the theory produces a city size distribution that is well approximated by Zipf's Law, but that also displays the observed systematic under-representation of both very small and very large cities. Using our model, we show that the dispersion of city sizes is consistent with the dispersion of productivity shocks found in the data.

Balanced Growth, Economic Growth, Scale Effects, Size Distribution of Cities, Zip's Law, Gibrat's Law

Abstract:
Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a general equilibrium theory of economic growth in an urban environment. In our theory, variation in the urban structure through the growth, birth, and death of cities is the margin that eliminates local increasing returns to yield constant returns to scale in the aggregate. We show that, consistent with the data, the theory produces a city size distribution that is well approximated by Zipf's law, but that also displays the observed systematic underrepresentation of both very small and very large cities. Using our model, we show that the dispersion of city sizes is consistent with the dispersion of productivity shocks found in the data.

Abstract:
Most economic activity occurs in cities. This creates a tension between local increasing returns, implied by the existence of cities, and aggregate constant returns, implied by balanced growth. To address this tension, we develop a theory of economic growth in an urban environment. We show that the urban structure is the margin that eliminates local increasing returns to yield constant returns to scale in the aggregate, which is sufficient to deliver balanced growth. In a multi-sector economy with specific factors and productivity shocks, the same mechanism leads to a city size distribution that is well described by a power distribution with coefficient one: Zipf's Law. Under certain assumptions our theory produces Zipf's Law exactly. More generally, it produces the systematic deviations from Zipf's Law observed in the data, including the under-representation of small cities and the absence of very large ones. In general, the model identifies the standard deviation of industry productivity shocks as the key parameter determining dispersion in the city size distribution. We present evidence that the relationship between the dispersion of city sizes and the variance of productivity shocks is consistent with the data.

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Abstract:
This paper uses a new dataset to study the relationship between economic output and sovereign default for the period 1820-2004. We find a negative but surprisingly weak relationship between output and default. Throughout history, countries have indeed defaulted during bad times (when output was relatively low), but they have also maintained debt service in the face of severe adverse shocks, and they have defaulted when domestic economic conditions were favorable. We show that this constitutes a puzzle for standard theories, which predict a much tighter negative relationship as default provides partial insurance against declines in output.

Default, Debt

Abstract:
What has been the effect of the shift in emerging market capital flows toward private sector borrowers? Are emerging market capital flows more efficient? If not, can controls on capital flows improve welfare? This paper shows that the answers depend on the form of default risk. When private loans are enforceable, but there is the risk that the government will default on behalf of all residents, private lending is inefficient and capital controls are potentially Pareto-improving. However, when private agents may individually default, capital flow subsidies are potentially Pareto-improving.

Capital flows, default, borrowing constraints, capital controls

Abstract:
Why do firm growth and exit rates decline with size? What determines the size distribution of firms? This paper presents a theory of firm dynamics that simultaneously rationalizes the basic facts on firm growth, exit, and size distributions. The theory emphasizes the accumulation of industry specific human capital in response to industry specific productivity shocks. The theory implies that firm growth and exit rates should decline faster with size, and the size distribution should have thinner tails, in sectors that use human capital less intensively, or correspondingly, physical capital more intensively. In line with the theory, we document substantial sectoral heterogeneity in US firm dynamics and firm size distributions, which is well explained by variation in physical capital intensities.

Abstract:
Negotiations to restructure sovereign debts are protracted, taking on average almost 8 years to complete. In this paper we construct a new database (the most extensive of its kind covering ninety recent sovereign defaults) and use it to document that these negotiations are also ineffective in both repaying creditors and reducing the debt burden countries face. Specifically, we find that creditor losses average roughly 40 per-cent, and that the average debtor exits default more highly indebted than when they entered default. To explain this apparent large inefficiency in negotiations, we present a theory of sovereign debt renegotiation in which delay arises from the same commitment problems that lead to default in the first place. A debt restructuring generates surplus for the parties at both the time of settlement and in the future. However, a creditor's ability to share in the future surplus is limited by the risk that the debtor will default on the settlement agreement. Hence, the debtor and creditor find it privately optimal to delay restructuring until future default risk is low, even though delay means some gains from trade remain unexploited. We show that a quantitative version of our theory can account for a number of stylized facts about sovereign default, as well as the new facts about debt restructurings that we document in this paper. Finally, we argue that our findings shed light on the existence of delays in bargaining in a wider range of contexts.

Sovereign debt, sovereign default, haircuts, recovery rates, bargaining, delays in bargaining

Abstract:
This paper examines two major risks to foreign investors: default on sovereign debt and expropriation of foreign direct investment, which we refer to collectively as "sovereign theft." Using a series of formal models, we analyze how the incentives to engage in sovereign theft vary with the state of the economy, the risk aversion of political leaders, and the nature of punishments for default and expropriation. We then document patterns of sovereign theft and foreign investment across much of the twentieth century. Our research, based on a new data set, reveals a striking asynchronicity: defaults and expropriations have occurred in alternating -- rather than coincident -- waves. Our findings shed new light on cooperation and conflict in the international economy.

sovereign debt, foreign direct investment, sovereign default, expropriation, nationalization

Abstract:
Negotiations between a country in default and its international creditors are modeled as a dynamic game in an environment of weak contractual enforcement. The country cannot borrow internationally until it settles with all creditors. Delay arises in equilibrium as creditors engage in strategic hold-up. The model confirms the conventional wisdom that delay increases with more creditors, and with the advent of "vulture" creditors. Contrary to conventional wisdom, putting collective action clauses into bond contracts may increase delay via free-riding on negotiation costs, even while preventing strategic holdup and reducing total negotiation costs. Secondary debt markets consolidate debt with high -- and disperse debt with low -- creditor bargaining power. Whether secondary markets reduce or increase delay depends on the interaction between strategic holdup and debt consolidation effects. The analysis contributes to the theory of multi-player dynamic timing games through a general treatment of the comparative dynamics used to answer key applied questions about sovereign debt negotiation.

Sovereign debt, sovereign default, bargaining, delays in bargaining, holdout, free riding, vulture creditors, secondary markets

Abstract:
Why do growth and net exit rates of establishments decline with size? What determines the size distribution of establishments? This paper presents a theory of establishment dynamics that simultaneously rationalizes the basic facts on economy-wide establishment growth, net exit, and size distributions. The theory emphasizes the accumulation of industry-specific human capital in response to industry-specific productivity shocks. It predicts that establishment growth and net exit rates should decline faster with size and that the establishment size distribution should have thinner tails in sectors that use human capital less intensively or physical capital more intensively. In line with the theory, the data show substantial sectoral heterogeneity in U.S. establishment size dynamics and distributions, which is well explained by variation in physical capital intensity.

Scale Effects, Establishment Dynamics, Size Distribution of Establishments, Zip's Law, Gibrat's Law