Allocative and Informational Externalities in Auctions and Related Mechanisms

We study the effects of allocative and informational externalities in (multi-object) auctions and related mechanisms. Such externalities naturally arise in models that embed auctions in larger economic contexts. In particular, they appear when there is downstream interaction among bidders after the auction has closed. The endogeneity of valuations is the main driving force behind many new, specific phenomena with allocative externalities: even in complete information settings, traditional auction formats need not be efficient, and they may give rise to multiple equilibria and strategic non-participation. But, in the absence of informational externalities, welfare maximization can be achieved by Vickrey-Clarke- Groves mechanisms. Welfare-maximizing Bayes-Nash implementation is, however, impossible in multi-object settings with informational externalities, unless the allocation problem is separable across objects (e.g. there are no allocative externalities nor complementarities) or signals are one-dimensional. Moreover, implementation of any choice function via ex-post equilibrium is generically impossible with informational externalities and multidimensional types. A theory of information constraints with multidimensional signals is rather complex, but indispensable for our study

Auctions with Financial Externalities

We study sealed-bid auctions with financial externalities, i.e., auctions in which losers’ utilities depend on how much the winner pays. In the unique symmetric equilibrium of the first-price sealed-bid auction (FPSB), larger financial externalities result in lower bids and in a lower expected revenue. The unique symmetric equilibrium of the second-price sealed-bid auction (SPSB) reveals ambiguous effects. We further show that a resale market does not have an effect on the equilibrium bids and that FPSB yields a lower expected revenue than SPSB. With a reserve price, we find an equilibrium for FPSB that involves pooling at the reserve price. For SPSB we derive a necessary and sufficient condition for the existence of a weakly separating equilibrium, and give an expression for the equilibrium.Auctions, financial externalities, reserve price, resale market

Land, Environmental Externalities and Tourism Development

In a two sectors dynamic model we analyze the process of tourism development based on the accumulation of capital (building of tourism facilities) and the reallocation of land from traditional activities to the tourism sector. The model incorporates the conflict between occupation of the territory by the tourism facilities, other productive activities and availability of cultural, natural and environmental assets that are valued by residents and visitors. We characterize the process of tourism development in two settings: the socially optimal solution and a situation where the costs of tourism expansion are external to the decision makers, where externalities on residents as well as intraindustry externalities are considered. Regarding the optimal solution, we show that it is optimal to limit tourism expansion before it reaches its maximum capacity even in a context where the economic attractiveness of tourism relative to other productive sectors rise continuously. However, in this context and when all the costs of tourism development are externalities the only limit to tourism quantitative expansion is its maximum capacity determined by the availability of land. Finally, we show that excessive environmental degradation from the future generations’ point of view is not a problem of discounting the future but rather a problem of externalities that affects negatively the current and future generations.Intertemporal land allocation, Structural economic change, Tourism industry

Optimal Soil Management and Environmental Policy

This paper studies the effects of environmental policy on the farmer’s soil optimal management. We consider a dynamic economic model of soil erosion where the intensity use of inputs allows the farmer to control soil losses. Therefore, inputs use induces a pollution which is accentuated by the soil fragility. We show, at the steady state, that the environmental tax induces a more conservative farmer behavior for soil, but in some cases it can exacerbate pollution. These effects can be moderated when farmers introduce abatement activity.Soil erosion, Pollution, Environmental policy, Optimal soil conservation, Abatement activities

Allocative and Informational Externalities in Auctions and Related Mechanisms

We study the effects of allocative and informational externalities in (multi-object) auctions and related mechanisms. Such externalities naturally arise in models that embed auctions in larger economic contexts. In particular, they appear when there is downstream interaction among bidders after the auction has closed. The endogeneity of valuations is the main driving force behind many new, specific phenomena with allocative externalities: even in complete information settings, traditional auction formats need not be efficient, and they may give rise to multiple equilibria and strategic non-participation. But, in the absence of informational externalities, welfare maximization can be achieved by Vickrey-Clarke- Groves mechanisms. Welfare-maximizing Bayes-Nash implementation is, however, impossible in multi-object settings with informational externalities, unless the allocation problem is separable across objects (e.g. there are no allocative externalities nor complementarities) or signals are one-dimensional. Moreover, implementation of any choice function via ex-post equilibrium is generically impossible with informational externalities and multidimensional types. A theory of information constraints with multidimensional signals is rather complex, but indispensable for our study.

Migration Dynamics

This paper tries to explain why most migration flows show some observable jumps in their processes, a phenomenon that seems to be sympathetic with the characteristic of irreversibility of migration. We present a real option model where the choice to migrate depends on both the differential wage between the host country and the country of origin, and on the probability of being fully integrated into the host country. The theoretical results show that the optimal migration decision of a single individual consists of waiting before migrating in a (coordinate) mass of individuals. The dimension of the migration flow depends on the behavioural characteristics of the ethnic groups: the more "sociable" they are, the larger the size of the wave and the lower the differential wage required. A second part of the paper is devoted to calibrating the model and simulating some migration flows to Italy in the last decade. The calibration is able to replicate the observable migration jumps in the short term. In particular, the calibrated model is able to conjecture the induced labour demand elasticity level of the host country and the behavioural rationale of the migrants.Migration, Real Option, Labour Market, Network Effect

Optimal Transfers and Participation Decisions in International Environmental Agreements

The literature on international environmental agreements has recognized the role transfers play in encouraging participation in international environmental agreements (IEAs), but the few results achieved so far are overly specific and do not exploit the full potential of transfers for successful treaty-making. Therefore, in this paper, we develop a framework that enables us to study the role of transfers in a more systematic way. We propose a design for transfers using both internal and external financial resources and making “welfare optimal agreements” self-enforcing. To illustrate the relevance of our transfer scheme for actual treaty-making, we use a well-known integrated assessment model of climate change to show how appropriate transfers may be able to induce almost all countries into signing a self-enforcing climate treaty.Self-enforcing international environmental agreements, Climate policy, Transfers