Optimal Money Burning: Theory and Application to Corporate Dividend Policy

We explore signaling behavior in settings with a discriminating signal and several costly nondiscriminating ( money burning ) activities. In settings where informed parties have many options for burning money, existing theory provides no basis for selecting one nondiscriminating activity over another. When senders have private information about the costs of these activities, each sender's indifference is resolved, the taxation of a nondiscriminating signal is Pareto improving, and the use of the taxed activity becomes more widespread as the tax rate rises. We apply this analysis to the theory of dividend signaling. The central testable implication of the model is verified empirically.

Control of coherent backscattering by breaking optical reciprocity

Reciprocity is a universal principle that has a profound impact on many areas of physics. A fundamental phenomenon in condensed-matter physics, optical physics and acoustics, arising from reciprocity, is the constructive interference of quantum or classical waves which propagate along time-reversed paths in disordered media, leading to, for example, weak localization and metal-insulator transition. Previous studies have shown that such coherent effects are suppressed when reciprocity is broken. Here we show that by breaking reciprocity in a controlled manner, we can tune, rather than simply suppress, these phenomena. In particular, we manipulate coherent backscattering of light, also known as weak localization. By utilizing a non-reciprocal magneto-optical effect, we control the interference between time-reversed paths inside a multimode fiber with strong mode mixing, and realize a continuous transition from the well-known peak to a dip in the backscattered intensity. Our results may open new possibilities for coherent control of classical and quantum waves in complex systemsComment: Comments are welcom

Comparative Advantage and Heterogeneous Firms

This paper presents a model of international trade that features heterogeneous firms, relativeendowment differences across countries, and consumer taste for variety. The paper demonstrates thatfirm reactions to trade liberalization generate endogenous Ricardian productivity responses at theindustry level that magnify countries' comparative advantage. Focusing on the wide range of firmlevelreactions to falling trade costs, the model also shows that, as trade costs fall, firms incomparative advantage industries are more likely to export, that relative firm size and the relativenumber of firms increases more in comparative advantage industries and that job turnover is higher incomparative advantage industries than in comparative disadvantage industries.Heckscher-Ohlin, international trade, inter-industry trade, intra-industry trade, trade costs,entry and exit

Product Choice and Product Switching

This paper develops a model of endogenous product selection by firms. The theory is motivated by new evidence we present on the importance of product switching by U.S. manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than 40% of firm output and almost half of existing products. The theoretical model incorporates heterogeneous firms, heterogeneous products, and ongoing entry and exit. In equilibrium, firm productivity is correlated with product fixed costs, with the most productive firms choosing to make the products with the highest fixed costs. Changes in market structure result in systematic patterns of firm entry/exit and product switching.

Factor Price Equalization in the UK?

This paper develops a general test of factor price equalization that is robust to unobserved regional productivity differences, unobserved region-industry factor quality differences and variation in production technology across industries. We test relative factor price equalization across regions of the UK. Although the UK is small and densely-populated, we find evidence of statistically significant and economically important departures from relative factor price equalization. Our estimates suggest three distinct relative factor price areas with a clear spatial structure. We explore explanations for these findings, including multiple cones of diversification, region-industry technology differences, agglomeration and increasing returns to scale.relative factor prices, diversification cones, technology, economic geography

Factor Price Equality and the Economies of the United States

We develop a methodology for identifying departures from relative factor price equality across regions that is valid under general assumptions about production, markets and factors. Application of this methodology to the United States reveals substantial and increasing deviations in relative skilled wages across labor markets in both 1972 and 1992. These deviations vary systematically with labor markets industry structure both in cross section and over time.Factor Price Equality, Regional Wages, Neoclassical Trade Theory, Labor Market Areas

Multi-Product Firms and Product Switching

This paper examines the frequency, pervasiveness and determinants of product switching among U.S. manufacturing firms. We find that two-thirds of firms alter their mix of five-digit SIC products every five years, that one-third of the increase in real U.S. manufacturing shipments between 1972 and 1997 is due to the net adding and dropping of products by survivors, and that firms are more likely to drop products which are younger and have smaller production volumes relative to other firms producing the same product. The product-switching behavior we observe is consistent with an extended model of industry dynamics emphasizing firm heterogeneity and self-selection into individual product markets. Our findings suggest that product switching contributes towards a reallocation of economic activity within firms towards more productive uses.Heterogeneous firms, Product differentiation, Product market entry and exit

Products and Productivity

Firms' decisions about which goods to produce are often made at a more disaggregate level than the data observed by empirical researchers. When products differ according to production technique or the way in which they enter demand, this data aggregation problem introduces a bias into standard measures of firm productivity. We develop a theoretical model of heterogeneous firms endogenously self-selecting into heterogeneous products. We characterize the bias introduced by unobserved variation in product mix across firms, and the implications of this bias for identifying firm and industry responses to exogenous policy shocks such as deregulation. More generally, we demonstrate that product switching gives rise to a richer set of industry-level dynamics than models where firm product mix remains fixed.Product choice, Productivity, Deregulation, Industry Evolution

Multi-Product Firms and Trade Liberalization

This paper develops a general equilibrium model of multi-product firms and analyzes their behavior during trade liberalization. Firm productivity in a given product is modeled as a combination of firm-level "ability" and firmproduct- level "expertise", both of which are stochastic and unknown prior to the firm's payment of a sunk cost of entry. Higher firm-level ability raises a firm's productivity across all products, which induces a positive correlation between a firm's intensive (output per product) and extensive (number of products) margins. Trade liberalization fosters productivity growth within and across firms and in aggregate by inducing firms to shed marginally productive products and forcing the lowest-productivity firms to exit. Though exporters produce a smaller range of products after liberalization, they increase the share of products sold abroad as well as exports per product. All of these adjustments are shown to be relatively more pronounced in countries' comparative advantage industries.heterogeneous firms, endogenous product scope, love of variety, core competency