It is commonplace in wage determination models and, in general, in economic models as a whole, to treat the workers' outside option as given. The main purpose of the present work is to remove, in various ways, this assumption. The work is organized as follows. The first chapter is devoted to introducing the thesis topic and the related literature. The second chapter describes an economy in which the workers hired by a firm acquire without cost a firm-specific skill that enables them to potentially become independent producers. Thus, by modelling explicitly the workers' decision to stay or to leave the firm, a stable earning profile for the economy is characterized. Such a stable earning profile can allow for a workers' compensation higher than the basic neoclassical wage and for pay differentials across industries even for initially homogenous workers. The third chapter shows that the existence of a concrete outside option for firms' managers can induce, under specific circumstances, oligopolistic firms to adopt restrictive output practises. In particular, the conditions under which, in a Cournot oligopoly, existing firms behave more collusively than in a standard Cournot model, are carefully defined. The fourth chapter considers the problem of producer co-operatives' (PCs) stability. It shows that PCs' instability argued in the literature can fail to hold in very competitive and low barrier-to-entry markets in which, potentially, dismissed members have a chance to set up new firms. In the fifth and conclusive chapter a new concept of core-stability for n-cooperative games is introduced and applied both to the problem of cartel formation under oligopoly and to an economy with a public good. Such a solution concept, denoted o-core, assumes that when a coalition deviates from an agreement, it possesses a first-mover advantage with respect to all other players.

This research examines the role of the abatement subsidy as a potential environmental policy option under various scenarios. This is achieved through a combination of theoretical and empirical analyses. The main motivation for this work stems from the existing literature on the abatement subsidy where its role seems to be a negative one from a policy standpoint. The reason for this is that in oligopoly models with free-entry the abatement subsidy encourages new firms into the market via higher profits thereby raising the level of total emissions in the industry, even though at the same time it lowers each firm's emissions. The overarching findings indicate that the abatement subsidy might play a role in environmental policy. The theoretical component of the work employs a symmetric free-entry Cournot oligopoly model both in a closed-economy and international settings. The key findings from these are that the subsidy lowers per-firm emissions and total industry emissions, and that the subsidy is welfare-enhancing when implemented multilaterally. As for the empirical component of the work, the analyses suggest that the subsidy is associated to lower per-firm emission levels and that the number of firms variable is not statistically significant.

This paper investigates the role of foreign competition and regional unemployment in influencing privatization policy for domestic firms. With a general model specifying the existence of foreign competition and regional unemployment, we find a negative relationship between presence of foreign competition and state ownership of the domestic firm within the same sector. We also find a positive relationship between unemployment rate in a region and state ownership of the domestic firm in the same region. Econometric analysis for China supports the theoretical findings.

In this thesis, our aim is to study a Cournot tatonnement system which exhibits destabilisation of the Cournot equilibrium as the number of firms increase. Our approach is to first consider the special case of firms behaving identically in a market share attraction model in two different adjustment process: Cournot tatonnement and bounded rationality adjustment. Results from the Cournot tatonnement system shows a superstable equilibrium in two firms model and an unstable equilibrium in a five firms model. In the five firms model, we show that introducing heterogeneity stabilises the Cournot equilibrium. For both two and five firms model, the differences of costs between firms are critical for the convergence of the system to the Cournot equilibrium. Lastly, we study the effect of entries and exits of firms on the number of active firms in the market. We discover that the market can sustain between two to four firms, and the factors are differences of costs and initial outputs between firms, and barriers to entries.

Building an asymmetric differentiated goods quantity competition model, the present paper explores how substitutability of products, one of the factors affecting the unilateral effect, determines horizontal mergers and acquisitions equilibrium and strategies. It seems intuitively obvious that the merger between firms with goods that are sufficiently close substitutes can be more profitable. However, this thesis's counter-intuitive results show that, for some parameter values, a merger is more profitable for the merging firm when the target firm produces a distant substitutes (i.e., when it is not the closest competitor to the acquiring firm in the market).The theoretical analysis shows that to merge with firm with low substitute parameter is more profitable provided that target firms are close enough and the both of them are distant enough from merging firms. The results in Cournot model and Bertrand have some similarities, for example, they both harm to consumer surplus and the optimal strategy harms most. For the difference, for example, in Coumot model, whenever it is profitable to merge with a distant competitor, it is the optimal strategy, while in Bertrand model, it depends. The paper also extends the classical "horizontal merger paradox" to a setting of asymmetric differentiated oligopoly.

The study analyzes the effects of three maize market policies on strategic price volatility, oligopoly/oligopsony market power, distribution of market surplus and total welfare. Policies of interest are privatization, the Current Malawi government policy and a proposed policy. The study first develops a workable theory then tests the various government policies in laboratory market experiments. The laboratory results indicate that the proposed policy was the most effective in reducing strategic volatility, but resulted in high output and low input prices. In terms of welfare distribution, privatization had highest consumer surplus followed by the current policy. The same was the case with producers’ surplus. However, traders’ profits were substantially higher in the proposed policy treatment. Total welfare was highest in the proposed policy followed by the current policy. In all, there appears there can be significant policy tradeoffs between market volatility, market power, surplus distribution and total welfare.

We consider a partial equilibrium Cournot-oligopolistic model in which the domestic market of two differentiated goods is served by a number of identical domestic firms and exports by foreign firms. In chapter 1, we characterize the optimality conditions with an emission standard and lump-sum tax to target the distortions, and we find the optimal instrument that targets the emission or pollution most efficiently. Through our study we find out that the use of right mix of environmental and non-environmental policy instruments could decrease emissions and increase welfare of the economy at the same time, even when there is foreign competition. Next, we introduce cross-border pollution and model pollution content tariff imposed on the imports from foreign country as one of the instruments for the domestic country in chapter 2. We first characterize the optimal values of the policy instruments and then design multilateral piecemeal policy reforms that unambiguously improve the welfare of the countries involved and reduce emissions. In chapter 3, we compare the effectiveness of two policy instruments in reducing pollution: subsidies tied to R&D and tariffs as trade barriers. Our paper shows that multilateral piecemeal policy reforms could be designed where 'carrots' in the form of tied subsidies to R&D would prove to be more beneficial than 'sticks' in the form of tariffs, in reducing the pollution and increasing the welfare for the two countries.

Tout d'abord, nous traitons des jeux d'oligopole de Cournot sous forme caractéristique gamma. Nous montrons que ces jeux sont balancés lorsque les fonctions de profit individuel sont concave. Ensuite, lorsque les fonctions de coût individuel sont linéaires, la «valeur au prorata de Nash» appartient au cœur. Par la suite, nous étudions les jeux d'oligopole de Cournot sous forme d'intervalle gamma. Nous prouvons que le cœur intervalle (standard) est non-vide si et seulement si le jeu d'oligopole de Cournot sous forme caractéristique gamma associé à la meilleure (plus faible) capacité qu'obtient chaque coalition admet un cœur non vide. Ensuite, nous analysons les jeux d'oligopole de Stackelberg sous forme caractéristique gamma. Nous montrons que le cœur est égal à l'ensemble des imputations. Ensuite, nous donnons une condition nécessaire et suffisante, qui dépend de l'hétérogénéité des coûts marginaux, assurant la non-vacuité du cœur. Enfin, nous considérons les jeux d'oligopole de Bertrand. Nous prouvons que les jeux sous les formes caractéristiques alpha ou bêta satisfont à la propriété de convexité. Ensuite, nous prouvons que la valeur de partage égalitaire appartient au cœur des jeux sous forme caractéristique gamma et nous donnons une condition suffisante qui assure que ces jeux satisfont à la propriété de convexité. Nous prolongeons cette analyse en supposant que les coûts marginaux sont distincts. Si la constante de la demande est suffisamment petite, alors les jeux sous forme caractéristique bêta satisfont à la propriété de balancement total. Autrement, ces jeux satisfont à la propriété de convexité. / In the first essay, we study Cournot oligopoly TU-games in gamma-characteristic function form. First, we prove that if any individual profit function is concave, such games are balanced. Then, when the individual cost functions are linear, we provide a solution in the core, called NP(Nash Prorata) value. The second essay considers Cournot oligopoly interval game in gamma-set function form. The first (second) result states that the interval (standard) core is non empty if and only if the Cournot oligopoly TU-game associated with the best (worst) worth of every coalition in its worth interval admits a non-empty core. In the thirdessay, we focus on Stackelberg oligopoly TU-games in gamma-characteristic function form. First, we prove that the core is equal to the set of imputations. Th en, we provide a necessary and sufficient condition, depending on the heterogeneity of firms' marginal costs, under which the core is non-empty. In the fourth essay, we show that Bertrand oligopoly TU-games inalpha and beta-characteristic function forms are convex. Then, we prove that the equal division solution is in the core of Bertrand oligopoly TU-games in gamma-characteristic function form and we give a sufficient condition under which such games are convex. The fifth essay studies the case where the marginal costs are distinct. If the intercept of demand is sufficiently small then games in _beta-characteristic function form are totally balanced. Otherwise, these games are convex.

O principal índice usado para medir concentrações horizontais é o Hirschmann-Herfindahl Index (HHI). Este índice tornou-se popular nos últimos anos devido ao seu apelo teórico e a sua simplicidade computacional, entretanto, apesar desta conveniência, o HHI é inaplicável na análise de mercados em que os compradores possuem poder de mercado. Isso ocorre porque o modelo de Cournot supõe que apenas os vendedores podem influenciar os preços. O erro causado pela aplicação inadequada do HHI é ainda maior quando o mercado considerado apresenta firmas verticalmente integradas. Diante disso, o objetivo deste trabalho é aplicar o MHI, medida de concentração sugerida por Hendricks e Mcafee (2007), na análise da aquisição da Agip pela BR, com vistas a identificar os impactos da operação sobre a concorrência, comparando os resultados com a análise da SEAE e a decisão do CADE. O MHI é capaz de captar a mudança de incentivos de todas as firmas do mercado estudado após o Ato de Concentração, e permite que o efeito líquido da integração seja medido através das variações das margens preço/custo das firmas da indústria. / The main index that is used to measure horizontal concentrations is the Hirschmann-Herfindahl Index (HHI). This index became popular in the last years due to its theoretical appeal and its computational simplicity. However, despite this convenience, the HHI is inapplicable in the analysis of markets where the purchasers have market power. This happens because the Cournot model assumes that only the sellers can influence the prices. The error caused by inadequate application of HHI is even bigger when the considerate market shows vertically integrated firms. In front of this, the objective of this work is apply the MHI, the concentration measure suggested by Hendricks e McAfee (2007), in the analysis of Agip acquisition by BR, with the purpose of identify the operation impacts in the competition, comparing the results with the SEAE analysis and the CADE decision. MHI is capable of catch the incentive change in all firms of the analyzed market after the Concentration Act, and allows that the operations net effect is measured through the price-cost margin variation.

This thesis is a collection of essays on the problem of overfishing in multifirm fisheries with a common property fish stock. We focus on the case of marine industrial fisheries, where the costs of preventing free riding tend to preclude cooperative harvesting. We study the overfishing problem by analysing harvesting incentives that stem from variations in (i) technological (cost, production and biological growth) functions, (ii) institutional factors (access schemes, regulatory agencies' instruments and their monitoring and enforcement powers, harvesting competition), and (iii) objective functions (private firms' planning horizons, welfare functions). Chapter 2 discusses conditions under which a fishing collapse can occur and examines the commonly held argument that fishing collapse is a public bad. Chapter 3 studies Chilean fishing regulations over the last five decades. The regulator's persistent inability to enforce annual quotas is analysed. Distributive disputes and triggered lobbying powers are examined. The late 1980s controversies over a new Chilean fishing law are analysed in-depth from this perspective. Chapter 4 explains the main motivations and key assumptions leading us to the oligopoly harvesting models of chapters 5 (static setting) and 6 (dynamic setting). These models focus on a deterministic single fish species and a single sector harvesting fishery composed of profit maximizing and price taking private firms that compete with each other by following non-cooperative harvesting strategies. These models examine the overfishing rankings that result from comparing Cournot-Nash and Stackelberg equilibria. First best and second best welfare benchmarks are considered. The Cournot-Nash setting is intended to illustrate a large number oligopolistic fishery, while the Stackelberg equilibrium is meant to be a first approximation to analyse the implications of harvesting fisheries subject to industrial concentration. Empirical evidence suggesting the presence of industrial concentration in a series of important marine industrial fisheries is described in chapters 3 and 4.