This dissertation extends previous research on bubbles by investigating whether changes in the financial asset prices of the S&P500 reflect changes in fundamentals. We propose that if this is not the case the volatility is due to a bubble. Hence, this is the general hypothesis from which several...

Replaced with revised version of paper 08/06/10.

This dissertation studies the roles of comparative advantage, monopolistic competition, and firm-level heterogeneity in international trade.The first essay investigates cross-country and cross-industry variation in the fractions of exporters among domestic firms. The paper presents a model of an...

Consumers voluntarily pay significant price premiums to acquire unobservable environmental attributes in green markets. This paper considers the performance of eco-certification policy under circumstances where consumers cannot discern environmental attributes in goods, but are able to form...

Estudiamos la política monetaria óptima desde una perspectiva atemporal en un modelo general de fijación de precios dependiente del estado (state-dependent pricing). Las empresas tienen poder monopolístico y están sujetas a perturbaciones idiosincráticas a sus costes de menú. Encontramos...