Equilibrium Size in Network with Indirect Network Externalities: a Comment

This commentary critically reviews a recent paper by Baraldi (2004). It shows that results obtained there are not robust, and may mot hold after the introduction of minor changes in the model structure. It is claimed that this is not a technical point, but relates to the fundamental nature of markets with indirect externalities.Network Externalities, Two-Sided Networks

Platform Competition with Endogenous Multihoming

A model of two-sided market (for credit cards) is introduced and discussed. In this model, agents can join none, one, or more than one platform (multihoming), depending on access prices and the choices made by agents on the opposite market side. Although emerging multihoming patterns are, clearly, one aspect of equilibrium in a two-sided market, this issue has not yet been thoroughly addressed in the literature. This paper provides a general theoretical framework, in which homing partitions are conceived as one aspect of market equilibrium, rather than being set ex-ante, through ad-hoc assumptions. The emergence of a specific equilibrium partition is a consequence of: (1) the structure of costs and benefits, (2) the degree and type of heterogeneity among agents, (3) the intensity of platform competition.Two-sided markets, Network externalities, Standards, Platforms, Multihoming

Water Scarcity and Virtual Water Trade in the Mediterranean

Virtual water trade refers to the implicit content of water in the production of goods and services. When trade is undertaken, there is an implicit exchange of water. Furthermore, when water gets scarce, water intensive goods become more expensive to produce and the economy compensates through higher water imports.This paper is about applying the concept of virtual water to the problem of future water scarcity in the Mediterranean area, also induced by the climate change. The aim is assessing to what extent water trade is a viable adaptation option to the problem of water scarcity. To this end, a computable general equilibrium model is extended with satellite data on sectoral water consumption, and used to assess future scenarios of water availability.It is found that virtual trade may curb the negative effect of water scarcity, yet the consequences in terms of income and welfare remain quite significant, especially for some regions.Computable General Equilibrium Models, Water, Virtual Water, Water Scarcity, Climate Change

Platform competition in two-sided markets: the case of payment networks

In this article, we construct a model to study competing payment networks, where networks offer differentiated products in terms of benefits to consumers and merchants. We study market equilibria for a variety of market structures: duopolistic competition and cartel, symmetric and asymmetric networks, and alternative assumptions about multihoming and consumer preferences. We find that competition unambiguously increases consumer and merchant welfare. We extend this analysis to competition among payment networks providing different payment instruments and find similar results.Payment systems ; Competition

Price Discrimination and Audience Composition in Advertising-Based Broadcasting

Traditionally, media like TV and radio, but also the Internet, have been characterized by free access (by consumers having the necessary hardware), with services supported through advertising revenues. Profitability in these markets depends on the capability of attracting audience. Strategic choices, however, also depend on the relationship with the dual market for advertising services. In this paper, a model is introduced, which has two distinguishing features. First, the multidimensional nature of competition in media markets is acknowledged, through explicit modeling of vertical and horizontal differentiation. Second, the price of advertising depends on the expected audience composition, not simply on its magnitude. It also depends on the broadcasters' capability of effectively price-discriminate among advertising customers. It is found that market equilibria depend on a number of critical factors: the amount and type of price discrimination in advertising, the correlation between formats and audience composition, the relative profitability of the different market segments, and diseconomies of scale in program quality.Advertising, Media Industries, Broadcasting, Price Discrimination, Television, Radio, Differentiation.

AN INTEGRATED ASSESSMENT MODEL OF ECONOMY-ENERGY-CLIMATE – THE MODEL WIAGEM: A COMMENT

climate change, integrated assessment, computable general equilibrium

Introducing Imperfect Competition in CGE Models: Technical Aspects and Implications

This paper considers the technical aspects and the consequences, in terms of simulation results and policy assessment, of introducing imperfect competition in a CGE model. The modifications to the standard CGE framework needed to model imperfect competition in some industries are briefly discussed. Next, the paper discusses whether, how much and why, those changes may affect the qualitative output of a typical simulation experiment. It is argued that technical choices made in designing the model structure may have a significant impact on the model behavior. This is especially evident when the output of the model, under an imperfect competition closure, is compared with that obtained under a standard closure, assuming perfect competition. As an illustration, a scenario of agricultural trade liberalization under alternative market structures is analyzed.Computable general equilibrium models, Imperfect competition, Oligopolistic models, Economies of scale, Empirical industrial organization, Agriculture, Trade liberalization, Trade policy

Climate Change and Extreme Events: an Assessment of Economic Implications

We use a general equilibrium model of the world economy, and a regional economic growth model, to assess the economic implications of vulnerability from extreme meteorological events, induced by the climate change. In particular, we first consider the impact of climate change on ENSO and NAO oceanic oscillations and, subsequently, the implied variation on regional expected damages. We found that expected damages from extreme events are increasing in the United States, Europe and Russia, and decreasing in energy exporting countries. Two economic implications are taken into account: (1) short-term impacts, due to changes in the demand structure, generated by higher/lower precautionary saving, and (2) variations in regional economic growth paths. We found that indirect stort-term effects(variations in savings due to higher or lower likelihood of natural disasters) can have an impact on regional economies, whose order of magnitude is comparable to the one of direct damages. On the other hand, we highlight that higher vulnerability from extreme events translates into higher volatility in the economic growth path, and vice versa.Climate Change, Extreme Events, Computable General Equilibrium Models, Precautionary Savings, Economic Growth

Social cost pricing when public transport is an option value

A well-known principle of welfare economics states that an efficient resources allocation can be achieved in a competitive economy when market prices are in line with social marginal costs. When applied to the transport sector, this implies that the price of the various transport modes should be made equal to the sum of marginal production and external costs, like congestion, accidents, pollution, and road maintenance. It is sometimes argued that the internalisation of external costs would bring about a change in demand patterns with a shift towards public transport and cleaner modes. But, public transport is already favoured by a discriminatory fiscal treatment. Whereas public services are normally (heavily) subsidised, private transport is taxed in several ways and, in some countries, quite substantially so. The application of the ìoptimal pricingî principle, therefore, critically depends on how the subsidisation of public services is interpreted. This paper addresses the issue of optimal pricing of urban transport, using different hypotheses about the treatment of public services. After reviewing some traditional arguments in favour of public transport subsidisation, a new approach, based on uncertainty and option values, is discussed. The implications of this approach are investigated by means of an applied model, where optimal prices for urban transport services in the city of Bologna are computed under alternative assumptions

Carbon leakage in a small open economy with capital mobility

The carbon emissions abatement, undertaken by some countries, may induce other countries to increase their own emissions. This effect, known as "carbon leakage", may be due to rather different mechanisms. The simplest case is when outside countries do not change their environmental policies and world prices are fixed. Unilateral policies may then induce a substitution of domestic production, generating emissions, with imports.This paper analyses the carbon leakage generated under the "small open economy" assumption, illustrating some findings through a numerical, dynamic, general equilibrium model of the Italian economy. The analysis highlights two main points. First, in a general equilibrium setting, the carbon leakage depends on both the substitution and income effects. Income effects, in turn, crucially depend on how carbon tax revenues are recycled, or pollution rights rents are assigned. Different recycling schemes have rather different impacts on the national income and on the trade-induced leakage. Second, carbon leakage may be significantly affected by the degree of capital mobility in international markets, because capital services enter the balance of trade. Capital outflows amount to exports of capital services, possibly financing the import of carbon-intensive goods. This result suggests that, in a world of increasingly integrated financial markets, unilateral environmental policies are becoming less effective, because of the existence of policy spill-overs