This thesis presents the main results of my research in the field of computational finance and portfolios optimization. We focus on pricing Asian basket options and portfolio problems in the presence of inflation with stochastic interest rates.<p><p>In Chapter 2, we concentrate upon the derivation of bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework.We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151–168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3–33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55–57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51–90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1–52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity<p><p>In Chapter 3, we propose some moment matching pricing methods for European-style discrete arithmetic Asian basket options in a Black & Scholes framework. We generalize the approach of Curran M. (1994) [Valuing Asian and portfolio by conditioning on the geometric mean price”, Management science, 40, 1705-1711] and of Deelstra G. Liinev J. and Vanmaele M. (2004) [Pricing of arithmetic basket options by conditioning”, Insurance: Mathematics & Economics] in several ways. We create a framework that allows for a whole class of conditioning random variables which are normally distributed. We moment match not only with a lognormal random variable but also with a log-extended-skew-normal random variable. We also improve the bounds of Deelstra G. Diallo I. and Vanmaele M. (2008). [Bounds for Asian basket options”, Journal of Computational and Applied Mathematics, 218, 215-228]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and<p>time-to-maturity.<p><p>In Chapter 4, we use the stochastic dynamic programming approach in order to extend<p>Brennan and Xia’s unconstrained optimal portfolio strategies by investigating the case in which interest rates and inflation rates follow affine dynamics which combine the model of Cox et al. (1985) [A Theory of the Term Structure of Interest Rates, Econometrica, 53(2), 385-408] and the model of Vasicek (1977) [An equilibrium characterization of the term structure, Journal of Financial Economics, 5, 177-188]. We first derive the nominal price of a zero coupon bond by using the evolution PDE which can be solved by reducing the problem to the solution of three ordinary differential equations (ODE). To solve the corresponding control problems we apply a verification theorem without the usual Lipschitz assumption given in Korn R. and Kraft H.(2001)[A Stochastic control approach to portfolio problems with stochastic interest rates, SIAM Journal on Control and Optimization, 40(4), 1250-1269] or Kraft(2004)[Optimal Portfolio with Stochastic Interest Rates and Defaultable Assets, Springer, Berlin].<p><p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The active use of macroeconomic policies to smooth economic fluctuations and, as a<p>consequence, the stance that policymakers should adopt over the business cycle, remain<p>controversial issues in the economic literature.<p>In the light of the dramatic experience of the early 1930s’ Great Depression, Keynes (1936)<p>argued that the market mechanism could not be relied upon to spontaneously recover from<p>a slump, and advocated counter-cyclical public spending and monetary policy to stimulate<p>demand. Albeit the Keynesian doctrine had largely influenced policymaking during<p>the two decades following World War II, it began to be seriously challenged in several<p>directions since the start of the 1970s. The introduction of rational expectations within<p>macroeconomic models implied that aggregate demand management could not stabilize<p>the economy’s responses to shocks (see in particular Sargent and Wallace (1975)). According<p>to this view, in fact, rational agents foresee the effects of the implemented policies, and<p>wage and price expectations are revised upwards accordingly. Therefore, real wages and<p>money balances remain constant and so does output. Within such a conceptual framework,<p>only unexpected policy interventions would have some short-run effects upon the economy.<p>The "real business cycle (RBC) theory", pioneered by Kydland and Prescott (1982), offered<p>an alternative explanation on the nature of fluctuations in economic activity, viewed<p>as reflecting the efficient responses of optimizing agents to exogenous sources of fluctuations, outside the direct control of policymakers. The normative implication was that<p>there should be no role for economic policy activism: fiscal and monetary policy should be<p>acyclical. The latest generation of New Keynesian dynamic stochastic general equilibrium<p>(DSGE) models builds on rigorous foundations in intertemporal optimizing behavior by<p>consumers and firms inherited from the RBC literature, but incorporates some frictions<p>in the adjustment of nominal and real quantities in response to macroeconomic shocks<p>(see Woodford (2003)). In such a framework, not only policy "surprises" may have an<p>impact on the economic activity, but also the way policymakers "systematically" respond<p>to exogenous sources of fluctuation plays a fundamental role in affecting the economic<p>activity, thereby rekindling interest in the use of counter-cyclical stabilization policies to<p>fine tune the business cycle.<p>Yet, despite impressive advances in the economic theory and econometric techniques, there are no definitive answers on the systematic stance policymakers should follow, and on the<p>effects of macroeconomic policies upon the economy. Against this background, the present thesis attempts to inspect the interrelations between macroeconomic policies and the economic activity from novel angles. Three contributions<p>are proposed. <p><p>In the first Chapter, I show that relying on the information actually available to policymakers when budgetary decisions are taken is of fundamental importance for the assessment of the cyclical stance of governments. In the second, I explore whether the effectiveness of fiscal shocks in spurring the economic activity has declined since the beginning of the 1970s. In the third, the impact of systematic monetary policies over U.S. industrial sectors is investigated. In the existing literature, empirical assessments of the historical stance of policymakers over the economic cycle have been mainly drawn from the estimation of "reduced-form" policy reaction functions (see in particular Taylor (1993) and Galì and Perotti (2003)). Such rules typically relate a policy instrument (a reference short-term interest rate or an indicator of discretionary fiscal policy) to a set of explanatory variables (notably inflation, the output gap and the debt-GDP ratio, as long as fiscal policy is concerned). Although these policy rules can be seen as simple approximations of what derived from an explicit optimization problem solved by social planners (see Kollmann (2007)), they received considerable attention since they proved to track the behavior of central banks and fiscal<p>policymakers relatively well. Typically, revised data, i.e. observations available to the<p>econometrician when the study is carried out, are used in the estimation of such policy<p>reaction functions. However, data available in "real-time" to policymakers may end up<p>to be remarkably different from what it is observed ex-post. Orphanides (2001), in an<p>innovative and thought-provoking paper on the U.S. monetary policy, challenged the way<p>policy evaluation was conducted that far by showing that unrealistic assumptions about<p>the timeliness of data availability may yield misleading descriptions of historical policy.<p>In the spirit of Orphanides (2001), in the first Chapter of this thesis I reconsider how<p>the intentional cyclical stance of fiscal authorities should be assessed. Importantly, in<p>the framework of fiscal policy rules, not only variables such as potential output and the<p>output gap are subject to measurement errors, but also the main discretionary "operating<p>instrument" in the hands of governments: the structural budget balance, i.e. the headline<p>government balance net of the effects due to automatic stabilizers. In fact, the actual<p>realization of planned fiscal measures may depend on several factors (such as the growth<p>rate of GDP, the implementation lags that often follow the adoption of many policy<p>measures, and others more) outside the direct and full control of fiscal authorities. Hence,<p>there might be sizeable differences between discretionary fiscal measures as planned in the<p>past and what it is observed ex-post. To be noted, this does not apply to monetary policy<p>since central bankers can control their operating interest rates with great accuracy.<p>When the historical behavior of fiscal authorities is analyzed from a real-time perspective, it emerges that the intentional stance has been counter-cyclical, especially during expansions, in the main OECD countries throughout the last thirteen years. This is at<p>odds with findings based on revised data, generally pointing to pro-cyclicality (see for example Gavin and Perotti (1997)). It is shown that empirical correlations among revision<p>errors and other second-order moments allow to predict the size and the sign of the bias<p>incurred in estimating the intentional stance of the policy when revised data are (mistakenly)<p>used. It addition, formal tests, based on a refinement of Hansen (1999), do not reject<p>the hypothesis that the intentional reaction of fiscal policy to the cycle is characterized by<p>two regimes: one counter-cyclical, when output is above its potential level, and the other<p>acyclical, in the opposite case. On the contrary, the use of revised data does not allow to identify any threshold effect.<p><p>The second and third Chapters of this thesis are devoted to the exploration of the impact<p>of fiscal and monetary policies upon the economy.<p>Over the last years, two approaches have been mainly followed by practitioners for the<p>estimation of the effects of macroeconomic policies on the real activity. On the one hand,<p>calibrated and estimated DSGE models allow to trace out the economy’s responses to<p>policy disturbances within an analytical framework derived from solid microeconomic<p>foundations. On the other, vector autoregressive (VAR) models continue to be largely<p>used since they have proved to fit macro data particularly well, albeit they cannot fully<p>serve to inspect structural interrelations among economic variables.<p>Yet, the typical DSGE and VAR models are designed to handle a limited number of variables<p>and are not suitable to address economic questions potentially involving a large<p>amount of information. In a DSGE framework, in fact, identifying aggregate shocks and<p>their propagation mechanism under a plausible set of theoretical restrictions becomes a<p>thorny issue when many variables are considered. As for VARs, estimation problems may<p>arise when models are specified in a large number of indicators (although latest contributions suggest that large-scale Bayesian VARs perform surprisingly well in forecasting.<p>See in particular Banbura, Giannone and Reichlin (2007)). As a consequence, the growing<p>popularity of factor models as effective econometric tools allowing to summarize in<p>a parsimonious and flexible manner large amounts of information may be explained not<p>only by their usefulness in deriving business cycle indicators and forecasting (see for example<p>Reichlin (2002) and D’Agostino and Giannone (2006)), but also, due to recent<p>developments, by their ability in evaluating the response of economic systems to identified<p>structural shocks (see Giannone, Reichlin and Sala (2002) and Forni, Giannone, Lippi<p>and Reichlin (2007)). Parallelly, some attempts have been made to combine the rigor of<p>DSGE models and the tractability of VAR ones, with the advantages of factor analysis<p>(see Boivin and Giannoni (2006) and Bernanke, Boivin and Eliasz (2005)).<p><p>The second Chapter of this thesis, based on a joint work with Agnès Bénassy-Quéré, presents an original study combining factor and VAR analysis in an encompassing framework,<p>to investigate how "unexpected" and "unsystematic" variations in taxes and government<p>spending feed through the economy in the home country and abroad. The domestic<p>impact of fiscal shocks in Germany, the U.K. and the U.S. and cross-border fiscal spillovers<p>from Germany to seven European economies is analyzed. In addition, the time evolution of domestic and cross-border tax and spending multipliers is explored. In fact, the way fiscal policy impacts on domestic and foreign economies<p>depends on several factors, possibly changing over time. In particular, the presence of excess<p>capacity, accommodating monetary policy, distortionary taxation and liquidity constrained<p>consumers, plays a prominent role in affecting how fiscal policies stimulate the<p>economic activity in the home country. The impact on foreign output crucially depends<p>on the importance of trade links, on real exchange rates and, in a monetary union, on<p>the sensitiveness of foreign economies to the common interest rate. It is well documented<p>that the last thirty years have witnessed frequent changes in the economic environment.<p>For instance, in most OECD countries, the monetary policy stance became less accommodating<p>in the 1980s compared to the 1970s, and more accommodating again in the<p>late 1990s and early 2000s. Moreover, financial markets have been heavily deregulated.<p>Hence, fiscal policy might have lost (or gained) power as a stimulating tool in the hands<p>of policymakers. Importantly, the issue of cross-border transmission of fiscal policy decisions is of the utmost relevance in the framework of the European Monetary Union and this explains why the debate on fiscal policy coordination has received so much attention since the adoption<p>of the single currency (see Ahearne, Sapir and Véron (2006) and European Commission<p>(2006)). It is found that over the period 1971 to 2004 tax shocks have generally been more effective in spurring domestic output than government spending shocks. Interestingly, the inclusion of common factors representing global economic phenomena yields to smaller multipliers<p>reconciling, at least for the U.K. the evidence from large-scale macroeconomic models,<p>generally finding feeble multipliers (see e.g. European Commission’s QUEST model), with<p>the one from a prototypical structural VAR pointing to stronger effects of fiscal policy.<p>When the estimation is performed recursively over samples of seventeen years of data, it<p>emerges that GDP multipliers have dropped drastically from early 1990s on, especially<p>in Germany (tax shocks) and in the U.S. (both tax and government spending shocks).<p>Moreover, the conduct of fiscal policy seems to have become less erratic, as documented<p>by a lower variance of fiscal shocks over time, and this might contribute to explain why<p>business cycles have shown less volatility in the countries under examination.<p>Expansionary fiscal policies in Germany do not generally have beggar-thy-neighbor effects<p>on other European countries. In particular, our results suggest that tax multipliers have<p>been positive but vanishing for neighboring countries (France, Italy, the Netherlands, Belgium and Austria), weak and mostly not significant for more remote ones (the U.K.<p>and Spain). Cross-border government spending multipliers are found to be monotonically<p>weak for all the subsamples considered.<p>Overall these findings suggest that fiscal "surprises", in the form of unexpected reductions in taxation and expansions in government consumption and investment, have become progressively less successful in stimulating the economic activity at the domestic level, indicating that, in the framework of the European Monetary Union, policymakers can only marginally rely on this discretionary instrument as a substitute for national monetary policies. <p><p>The objective of the third chapter is to inspect the role of monetary policy in the U.S. business cycle. In particular, the effects of "systematic" monetary policies upon several industrial sectors is investigated. The focus is on the systematic, or endogenous, component of monetary policy (i.e. the one which is related to the economic activity in a stable and predictable way), for three main reasons. First, endogenous monetary policies are likely to have sizeable real effects, if agents’ expectations are not perfectly rational and if there are some nominal and real frictions in a market. Second, as widely documented, the variability of the monetary instrument and of the main macro variables is only marginally explained by monetary "shocks", defined as unexpected and exogenous variations in monetary conditions. Third, monetary shocks can be simply interpreted as measurement errors (see Christiano, Eichenbaum<p>and Evans (1998)). Hence, the systematic component of monetary policy is likely to have played a fundamental role in affecting business cycle fluctuations. The strategy to isolate the impact of systematic policies relies on a counterfactual experiment, within a (calibrated or estimated) macroeconomic model. As a first step, a macroeconomic shock to which monetary policy is likely to respond should be selected,<p>and its effects upon the economy simulated. Then, the impact of such shock should be<p>evaluated under a “policy-inactive” scenario, assuming that the central bank does not respond<p>to it. Finally, by comparing the responses of the variables of interest under these<p>two scenarios, some evidence on the sensitivity of the economic system to the endogenous<p>component of the policy can be drawn (see Bernanke, Gertler and Watson (1997)).<p>Such kind of exercise is first proposed within a stylized DSGE model, where the analytical<p>solution of the model can be derived. However, as argued, large-scale multi-sector DSGE<p>models can be solved only numerically, thus implying that the proposed experiment cannot<p>be carried out. Moreover, the estimation of DSGE models becomes a thorny issue when many variables are incorporated (see Canova and Sala (2007)). For these arguments, a less “structural”, but more tractable, approach is followed, where a minimal amount of<p>identifying restrictions is imposed. In particular, a factor model econometric approach<p>is adopted (see in particular Giannone, Reichlin and Sala (2002) and Forni, Giannone,<p>Lippi and Reichlin (2007)). In this framework, I develop a technique to perform the counterfactual experiment needed to assess the impact of systematic monetary policies.<p>It is found that 2 and 3-digit SIC U.S. industries are characterized by very heterogeneous degrees of sensitivity to the endogenous component of the policy. Notably, the industries showing the strongest sensitivities are the ones producing durable goods and metallic<p>materials. Non-durable good producers, food, textile and lumber producing industries are<p>the least affected. In addition, it is highlighted that industrial sectors adjusting prices relatively infrequently are the most "vulnerable" ones. In fact, firms in this group are likely to increase quantities, rather than prices, following a shock positively hitting the economy. Finally, it emerges that sectors characterized by a higher recourse to external sources to finance investments, and sectors investing relatively more in new plants and machineries, are the most affected by endogenous monetary actions. / Doctorat en sciences économiques, Orientation économie / info:eu-repo/semantics/nonPublished

Cette thèse étudie différents mécanismes par lesquels l'immobilier des entreprises influe sur l'investissement, l'emploi et la mobilité des Sociétés Non-Financières (SNFs). L'actif immobilier représente une part très importante de la valeur de l'actif des entreprises et les locaux constituent souvent un des principaux postes de dépenses des SNFs. Les prix de l'immobilier ont un effet sur la valeur de l'actif que les entreprises peuvent déposer en garantie et sur le coût des facteurs de production. Dans le cadre d'un marché du crédit frictionnel, la capacité d'emprunt des entreprises peut être accrue par une hausse de la valeur de marché des actifs. Les deux premiers chapitres de cette thèse étudient cet effet de collatéral et ses conséquences sur l'investissement et l'emploi. Le premier chapitre présente une modélisation dynamique qui met l'accent sur le comportement des variables relatives au marché du travail. Le second chapitre explore les effets hétérogènes entre entreprises en analysant des données microéconomiques. Le dernier chapitre porte sur les conséquences des spécificités des coûts d'ajustement de l'immobilier. En étudiant le comportement de mobilité d'entreprises qui sont soumises à des coûts de déménagement différenciés, nous mettons en évidence un effet notable des coûts associés au changement de la taille des locaux sur la dynamique de l'emploi. / This thesis studies channels through which corporate real-estate affects investment, employment and mobility of Non-Financial Corporations (NFCs). Real-estate assets account for a sizable share of firms' asset value and premises are often one of the main expenditure items of NFCs. Real-estate prices hence have a bearing on the value of firms' pledgeable assets and on the cost of inputs. In a frictional credit market, the firms' borrowing capacity can be enhanced by an increase in asset's value. The first two chapters of this thesis study this collateral channel and its effects on investment and employment. The first chapter proposes a dynamic setting with a focus on labor market variables whereas the second explores heterogeneous effects across firms, based on micro-data. The last chapter examines the consequences of the peculiarities of real-estate adjustment costs. Studying the relocation behaviour of firms facing varying moving costs, we document important effects of the costs associated with a change in the size of the premises on the employment dynamics.

L’objectif de ce travail est d’analyser les implications du choix de régime de change dans les pays émergents et en développement, ainsi que d’apporter des éclaircissements sur les facteurs jouant un rôle important dans le déclenchement des crises (de change, bancaires, financières…) dans ces pays. Pour cela, l’analyse se tourne, dans un premier temps, vers la question du choix de régime de change optimal. Cette partie du travail s’appuie principalement sur un grand nombre de travaux théoriques et empiriques traitant de cette question, pour mettre en lumière les implications de ce choix, tout en tenant compte des particularités du groupe de pays qui font l’objet de cette étude. Dans une deuxième partie nous nous intéressons aux crises et les facteurs qui jouent un rôle majeur dans leur incidence. Ainsi, après une revue des différents modèles de crises afin d’identifier les variables d’intérêt, nous construisons deux modèles de prédiction des crises, ou « d’alarme précoce ». Enfin, la troisième partie du travail rassemble les enseignements tirés des deux parties précédentes pour traiter d’une question qui prend une ampleur croissante dans ces pays : étant donné la logique d’intégration financière mondiale et les avantages présentés par un régime de changes flottants dans un tel contexte, de quelle manière un pays envisageant un sortie vers ce régime de change peut-il la planifier, et à quel moment doit-il l’entreprendre, pour réussir une sortie sans crise majeure, que nous qualifions de sortie « ordonnée » ? Pour répondre à cette question, nous nous appuyons sur des expériences passées qui nous permettent de construire un modèle identifiant les variables susceptibles d’accroître la probabilité d’une sortie ordonnée. Nous complétons ce modèle par quelques considérations supplémentaires qui constituent des conditions importantes à la réussite d’une sortie ordonnée. L’objectif est d’apporter des recommandations susceptibles de faciliter cette transition. / The aim of this work is to analyze the implications of exchange rate regime choice in developing and emerging market economies, as well as highlight the factors that play a major role in the incidence of crises (currency, banking, financial…) in these countries. With this aim in mind, we start our analysis by turning to the question of the choice of the optimal exchange rate regime. This part of our work draws on a large number of both theoretical and empirical works evoking this question in order to determine the implications of this choice, all the while keeping in mind the fact that this particular group of countries present certain characteristics that are usually absent in their industrial counterparts. The second part of our work concentrates more specifically on crises and the factors that play a major role in their occurrence. Therefore, following a brief overview of different crisis models in order to identify the variables of interest, we propose two models for crisis prediction, or “Early Warning Systems”. Finally, the third and final part of our work brings together the conclusions of the earlier parts in order to address an issue that is becoming increasingly important in developing and emerging market economies: given their greater integration in international financial and capital markets, as well as the incontestable advantages of a floating exchange rate regime in such a context, how can a country wishing to exit to a more flexible exchange rate arrangement undertake such a transition, and when, in order to achieve an “orderly” exit, that is, an exit that is not accompanied by a crisis? To answer this question we draw on past experiences to construct a model indentifying the economic variables that might increase the probability of an orderly exit. We complete this model with a number of additional considerations that have recently emerged as important preconditions for an orderly exit, in order to provide some useful policy recommendations facilitating this transition.

No description available.

Les crises financières et les problèmes se formaient mais les indicateurs ne sont pas précis pour permettre une intervention réglementaire. La thèse propose un modèle dynamique pour le système bancaire avec une banque centrale afin de calculer un indicateur de faillite en fonction de la probabilité qu'une banque soit en faillite et les pertes rencontrées dans le réseau financier, une méthodologie qui peut améliorer la mesure, le suivi et la gestion du risque systémique.La thèse propose également des mécanismes de compensation : 1- avec un modèle considérant l'ancienneté du passif et avec un type d'actif liquide dont la vente excessive conduit à un impact sur le marché, 2 - avec un modèle considérant les participations croisées entres les banques dont les engagements interbancaires sont de différentes séniorités et avec un type d'actif liquide dont la vente excessive conduit à un impact sur le marché. / Financial crisis pose important theoretical problems on creating reliable indicator of stability of financial systems on which basis the regulators could intervene. The thesis proposes a dynamic model of banking system were the central bank can calculate an indicator of potential defaults taking into consideration the probability for a bank to default and the losses encountered in the financial network, a methodology that can improve the measurement, monitoring, and the management of the systemic risk. The thesis also suggests a clearing mechanisms : 1- in a model with seniority of liabilities and one type of liquid asset whose fire sale has a market impact, 2 - in a model with crossholdings among the banks whose interbank liabilities may be senior and junior and with one liquid asset whose firing sale has a market impact.

La liberté contractuelle du banquier est une liberté parmi d’autres. Cependant, elle est la plus sensible dans lamesure où elle peut avoir des répercussions sur son activité. A priori sans limites aujourd’hui, cette liberté auraitmême des conséquences indéniables sur la sécurité du système financier en facilitant le phénomène des« bulles ». Le contrat, situé au coeur de l’activité bancaire et financière, serait ainsi la cause de cette réalité. Leschocs récents, telles les crises financières, imposent l´examen détaillé des opérations bancaires nationales maisaussi internationales, notamment celles les plus dangereuses. Encore méconnue, la mesure de la libertécontractuelle du banquier s’avère nécessaire pour en proposer une relecture. L’objectif n’est donc pas d’excluretoute liberté au banquier mais de définir le degré de liberté contractuelle à lui accorder pour chaque opération.L´idée étant de lui octroyer un niveau satisfaisant de liberté tout en assurant la sécurité du système financier.L’enjeu repose finalement sur la conciliation de l’impératif contractuel, résultant de la liberté contractuelle dubanquier, avec l’impératif de sécurité du système financier, nécessaire à la pérennité des banques et del’économie mondiale. / The contractual freedom of the banker is a freedom among the others. However, it is the most sensitive in so faras it can affect on his activity. Apparently unlimited today, this freedom would have even undeniableconsequences on the safety of the financial system by facilitating the phenomenon of “speculative bubbles”. Thecontract, situated in the heart of the banking and financial activity, would be thus the cause of this reality. Therecent shocks, such as financial crises, require the detailed examination of the national but also internationalbank transactions, especially the most dangerous. Still ignored, the measurement of the contractual freedom ofthe banker proves to be necessary to propose a review. The aim is not thus to rule any banker’s freedom out butto define the degree of contractual freedom to grant to him for each transaction. The idea being to grant him asatisfactory level of freedom while ensuring the safety of financial system. The stake rests finally on theconciliation of the contractual requirement, resulting from the contractual freedom of the banker, with the safetyrequirement of the financial system, necessary for the sustainability of banks and worldwide economy.

Le patriotisme économique relève davantage du discours politique que d’un concept juridique. Il fait référence aux comportements des citoyens, des entreprises et des États. Celui des États peut en substance être défini comme la défense par ces derniers de leurs entreprises stratégiques. Ainsi précisée, cette notion se traduit en pratique par l’institution de dispositifs nationaux de contrôle des investissements étrangers, par la stabilisation de l’actionnariat des entreprises stratégiques au travers des prises de participations des fonds stratégiques d’investissement, ou encore, par l’octroi de droits exclusifs ou spéciaux. De tels comportements peuvent contrarier les principes de la libre circulation - capitaux, établissement - et de la libre concurrence. Ces principes souffrent cependant de tempéraments qui laissent une certaine marge de manœuvre aux États, laquelle est cependant étroite. Cette étroitesse conduit ces derniers à être sans cesse inventifs pour défendre leurs entreprises. Le droit des sociétés offre de ce point de vue des outils pertinents pouvant servir ce dessein. Mais, la protection des entreprises stratégiques en dehors des exceptions ou dérogations prévues par le traité, qui traduit la persistance des replis nationaux, n’est pas sans relever les limites de l’opposition systématique aux patriotismes économiques nationaux. De plus, une telle faculté risque de fragiliser l’achèvement du marché intérieur. Pour ces raisons, il importe pour les autorités de l’Union européenne, d’engager une dynamique permettant de mieux prendre en compte les préoccupations patriotiques des États. Agrégée à un concept cohérent, à savoir le patriotisme économique européen, une telle démarche consisterait à instaurer une politique d’investissement commune qui sache conjuguer ouverture aux capitaux étrangers et préservation des secteurs stratégiques. Mais, l’efficacité d’une telle politique est relative. C’est pourquoi, on doit lui adjoindre un cadre autonome de contrôle des investissements en provenance des pays tiers. / Economic patriotism is more a political speech than a legal concept. It refers to behaviors of citizens, companies and governments. Concerning States, this concept can essentially be defined as defense of strategic companies. In practice, this notion is reflected by the institution of national systems of foreign investments control, by stabilizing the shareholding of companies through strategic investment funds, or by granting exclusive or special rights. These behaviors can antagonize the European Union law. However, this law allows exceptions that offer opportunities to States. But the flexibility of States is close. This narrowness leds them to be constantly inventive to defend their strategic companies. Business law allows such an approach. But the protection of strategic companies without the exceptions or derogations permitted by the treaty, which reflects the persistence of domestic markets partitioning, is not without showing the limits of systematic opposition to national economic patriotisms. In addition, such a power may weaken the completion of the internal market. For these reasons, it is important for the authorities of the European Union, to initiate a dynamic that can permit to take better account of the States patriotic concerns. Aggregate to a coherent concept, namely the european economic patriotism, such an approach will permit to establish a common investment policy that can combine openness to foreign investments and preservation of strategic sectors. But, the effectiveness of such a policy is relative. That’s why, it’s crucial to add to it an autonomous control framework for investments coming from non-member countries.

Cette thèse sur la nouvelle gouvernance financière publique dans le système des Nations Unies se présente en deux parties : première partie - La mise en œuvre de la nouvelle gouvernance financière publique dans les organisations du système des Nations Unies ; et deuxième partie - Le renforcement de la nouvelle gouvernance financière publique dans les organisations du système des Nations Unies. Pour notre étude, nous avons appliqué aux organisations du système des Nations Unies les éléments pertinents du cadre de référence établi par certains organes subsidiaires pour la nouvelle gouvernance financière publique, en particulier ceux qui se rapportent au cycle allant de la planification à l'établissement des rapports, dont il est question plus en détail dans les deux parties de la thèse. Ce cadre de référence vaut pour la nouvelle gouvernance financière publique dans son ensemble. Or. pour certaines activités spéciales, seule la budgétisation axée sur les résultats est pratiquée. Certains éléments du cadre de référence ne s'appliquent donc pas dans le contexte de la présente thèse, cependant d'autres aspects jugés importants pour toute démarche de la nouvelle gouvernance financière publique sont pris en compte. / This thesis on the new public financial governance in the United Nations system has two parts : first part - the implementation of the new public financial governance in organizations of the United Nations system ; and second part - the strengthening of the new public financial governance in organizations of the United Nations system. For our study, we applied the relevant elements of the terms of reference established by certain subsidiary bodies for new public financial governance in organizations of the United Nations system, in particular those that relate to the cycle from planning to establish reports being discussed more in detail in the two parts of the thesis. This framework applies to the new public financial governance as a whole. However, for some special activities, only the results-based budgeting is practiced. Some elements of the terms of reference do not therefore apply in the context of the present thesis, however, other aspects considered important for any new public financial governance process are taken into account.

Depuis plus de deux décennies, un nombre d’Etats africains dits du champ de la Conférence Internationale sur la Région des Grands Lacs sont enlisés dans des conflits armés à la fois intra-étatiques et internationalisés. Du génocide rwandais aux guerres civiles au Congo-Brazzaville, en Angola, en Ouganda, au Burundi, ou encore aux violences politiques armées incessantes en Centrafrique, en passant par la Grande Guerre Africaine en RDC, nombreux et importants sont les mécanismes de résolution de conflits qui ont été expérimentés, de nature aussi bien bilatérale, communautaire, régionale, qu’onusienne. Malheureusement, les concepts de sortie de crise et de reconstruction post-conflit demeurent de vains mots, eu égard aux résurgences et aux prolongements des conflits dans cette Région. Ainsi, en mobilisant l’approche néo-élitiste s’inscrivant dans un dépassement de la réalité empirique, après avoir passé en revue toutes les grandes théories philosophico-politico-sociologiques des élites, défendues par les auteurs classiques comme Wilfredo Pareto, Gaetano Mosca etc., d’un côté, et en recourant à la théorie de Johan Galtung de paix négative versus paix positive, d’autre part, cette étude se propose de mettre en évidence le rôle des élites dirigeantes dans la dynamique de pacification de la Région. Et après avoir défini et déterminé celles-ci, le travail démontre la difficulté de résoudre les conflits due à l’hétérogénéité sociologique caractérisant la Région. Puis, il souligne les mécanismes de l’entretien d’une paix négative par les élites dirigeantes, en interaction avec les autres protagonistes. / For more than two decades, a number of African States within the scope of the International Conference on the Great Lakes Region have sunk into both armed intrastate and domestic conflicts. From the Rwandan genocide to civil wars in Congo-Brazzaville, Angola, Uganda, and Burundi, or the constantly armed political violence in the Central African Republic (CAR), through the Great African War in the Democratic Republic of Congo (DRC), numerous and important mechanisms for conflict resolution have been experienced, bilateral, communitarian, regional, as well as Onusian. Unfortunately, the concepts relative to the end of crisis and post-conflict reconstruction still remain empty words, given the revivals and extensions of conflicts in that Region. Thus, by mobilizing the neo-elitist approach which goes the empirical reality, after reviewing all the major elitist philosophical, political and sociological theories defended by the classical authors such as Wilfredo Pareto, Gaetano Mosca, etc. On one hand, and by resorting to Johan Galtung’s theory on negative peace versus positive peace, on the other, this dissertation aims at highlighting the role played by governing Elites in the peace process within the Region. After defining these elites, this monography shows the difficulties of solving conflicts due to the regional sociodemographic heterogeneity. Then, it emphasizes mechanisms for keeping negative peace by the governing Elites, in interaction with other protagonists.