Recent theories of economic growth, including Romer (1986), Porter (1989) and Jacobs (1969), have stressed the role of technological spillovers in generating growth. Because such knowledge spillovers are particularly effective in cities, where communication between people is more extensive, data...

This paper studies foundational issues in securities markets models with fixed costs of trading, i.e. transactions costs that are bounded regardless of the transaction size, such as: fixed brokerage fees, investment taxes, operational and processing costs, or opportunity costs. We show that the...

This paper studies foundational issues in securities markets models with fixed costs of trading, i.e. transaction costs that are bounded regardless of the transaction size, such as fixed brokerage fees, investment taxes, operational and processing costs, or opportunity costs. We show that the...

This paper studies foundational issues in securities markets models with fixed costs of trading, i.e. transaction costs that are bounded regardless of the transaction size, such as : fixed brokerage fees, investment taxes, operational and processing costs, or opportunity costs. We show that the...

In this paper we study some foundational issues in the theory of asset pricing with market frictions. We model market frictions by letting the set of marketed contingent claims (the opportunity set) be a convex set, and the pricing rule at which these claims are available be convex. This is the...

This paper studies foundational issues in securities markets models with fixed costs of trading, i.e. transactions costs that are bounded regardless of the transaction size, such as fixed brokerage fees, investment taxes, operational, and processing costs or opportunity costs. We show that the...

In this paper we provide a price characterization of efficient consumption bundles in multiperiod economies with market frictions. Efficient consumption bundles are those that are chosen by at least one rational agent with monotonic state-independent and risk-averse preferences and a given...

Assesses the theories of knowledge spillover and growth proposed by Romer, Porter, and Jacobs by focusing on the largest industries in 170 U.S. cities. While the theories of Romer and Porter both emphasize spillovers within an industry, Romer predicts that a local monopoly is better for growth...