Le premier chapitre questionne l'intuition conventionnelle selon laquelle une forte concentration au plus haut de la distribution des revenus devrait favoriser l'émergence de bulles d'actifs rationnelles. J'utilise un modèle OLG avec des fictions financières et des agents hétérogènes qui diffèrent en termes de taux d'épargne, portefeuilles d'actifs et talents. Je montre qu'une forte concentration promeut l'émergence de bulles si et seulement si ces bulles sont illiquides ou si tous les actifs offrent les mêmes rendements. A l'inverse, lorsque les bulles sont liquides et les actifs liquides paient une prime de liquidité, une faible concentration promeut l'émergence de bulles. Le deuxième papier étudie les conditions sous lesquelles une bulle d'actif augmente le PIB dans un modèle OLG-Nouveau Keynesien incluant le capital. Je montre que la stagnation séculaire est une condition nécessaire mais non suffisante. En effet, les bulles ne stimulent le PIB que si la demande agrégée est très fortement déficiente. Le troisième papier démontre que les modèle Nouveaux Keynesiens (NK) font des prédictions paradoxales lorsque la demande agrégée est chroniquement déficiente - un boom séculaire plutôt qu'une stagnation séculaire, et analyse comment ajuster ces modèles pour qu'ils deviennent viables dans l'environnement actuel. Je souligne l'importance cruciale des élasticités de l'offre et de la demande d'actifs par rapport au PIB à long terme ; j'effectue également une connexion entre le boom séculaire et d'autres prévisions paradoxales du modèle NK. / The first chapter questions the conventional intuition that a high concentration of income at the top of the distribution should promote the emergence of rational asset bubbles. I use an OLG model with financial fictions and heterogeneous agents that differ in terms of savings rate, portfolio choices and skills. I show that a high concentration at the top promotes the emergence of asset bubbles if and only if those asset bubbles are illiquid or financial markets are arbitrage-free. Instead, if asset bubbles are liquid and liquid assets pay a premium under illiquid assets, a low concentration promotes the emergence of asset bubbles. The second chapter studies the circumstances under which asset bubbles are expansionary in an OLG-New Keynesian that includes capital. I show that secular stagnation is a necessary but not sufficient condition. Indeed, asset bubbles stimulate investment, consumption and output if and only if there's a strong shortage of aggregate demand. Finally, the third paper shows that "standard" New Keynesian models make puzzling predictions when aggregate demand is chronically deficient they predict a secular boom, and seeks to understand how those models must be adjusted to analyze secular stagnation. I emphasize the crucial role of the long run elasticities of asset demand and supply with respect to the output gap in general equilibrium; and I also connect the secular boom to other puzzling predictions of the New Keynesian model.

Orientador: Eduardo Strachman / Resumo: Em um ambiente de globalização financeira, a taxa de câmbio se coloca como uma variável de relativa importância para uma economia. A justificativa para isso está centrada no fato de que ela representa um dos principais preços relativos de uma economia e, portanto, estudos que buscam descobri a sua determinação, os seus movimentos e a sua dinâmica estão constantemente presentes na literatura econômica. A emergência sobre essa temática surgiu após o fim do acordo de Bretton Woods em 1973, no qual o seu fim resultou em mudanças na arquitetura do sistema monetário e financeiro internacional, modificando, entre várias coisas, o relacionamento dos países com as suas respectivas taxas de câmbio. Em alguns países o regime de câmbio flutuante foi adotado em detrimento do regime de câmbio fixo, e com isso as taxas de câmbio passaram a apresentar um comportamento altamente volátil, o que despertou a curiosidade sobre este fato. O comportamento volátil das taxas de câmbio somado a propagação da globalização financeira, ocasionou o processo de “financeirização” das taxas. Este processo estreitava a relação do câmbio com os fluxos de capitais de curto prazo, além de permitir ganhos especulativos com a variação cambial. Com essa nova realidade, alguns estudos emergiram com o objetivo de explicar a nova dinâmica cambial. É neste contexto que surgiu a abordagem pós-keynesiana de determinação cambial, que traz como um dos fundamentos a criação do Modelo Mental. O modelo mental seria um esquema... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The following study aims to verify the applicability of the mental model to explain the dynamics of the exchange rate in Brazil from 2001 to 2018. The end of Bretton Woods agreement in 1973 led to changes in the international financial architecture, such as the ones observed in the relationship between a country with its exchange rate. As some countries chose the floating Exchange rate regime instead of the fixed one. the exchange rates of the following years presented a highly volatile behavior. This behavior added to financial globalization, growing demand for liquid assets, and deep markets, caused a financialization of the Exchange rate. This process strengthened the relation of the Exchange rate to short-term capital flows. In addition, it permitted speculation profits from the exchange variation. In this same period, lots of theories and models were formulated trying to explain this new outline. Among them, there is the post Keynesian approach of exchange rate determination. According to it, agents’ expectations and short-term capital flows are the driving force of currency movements. Thus, this approach created a mental model which delineates the development of those expectations. The complete mental model has three phases; indicators, base factors, and processes, and it will be used as part of this paper methodology. As this study is a descriptive and explanatory, its methodological procedures were divided in two parts. First, there is a descriptive statistical analys... (Complete abstract click electronic access below) / Mestre

A thesis submitted to the Faculty of Commerce, Law and Management, University of the Witwatersrand, Johannesburg, in fullment of the requirements for the Doctor of Philosophy in Economics Degree, June 2017 / This thesis contains three main chapters. The rst chapter employs wageprice spirals to generate ination forecasts for Australia, Canada, France, South Korea, South Africa, United Kingdom and the United States. We use three competing specications of the wage-price spirals, and test which specication provides the best forecasts of price ination. For each specication we provide one quarter, four quarter and eight quarter ahead dynamic forecasts of price ination. The rst two wage-price spirals in the rst chapter are from the Keynesian tradition from te standpoint of expectations formation. The chapter also considers the New Keynesian wage-price spiral. We use the Root Means Square Error and the Clark and West statistic to compare the performance of ination forecasts from the three competing wage-price spirals that we consider in the rst chapter of the thesis. We nd that the New Keynesian wage and price specication su⁄ers from the wrong sign problem, and its forecasts of price ination generally outperform those from the old Keynesian wage price spiral for the eight quarter ahead time horizon. The usefulness of this nding to the conduct of monetary policy is limited due to the wrong sign problem of the forcing variable in the New Keynesian wageprice spiral. We also nd that the Flaschel type specication of price and wage ination produce four and eight quarter head ination forecasts that are better than those from the Fair type specication. We further nd that the Fair type specication price and wage equation produce the best forecasts of ination for the one quarter ahead time horizon. In the second chapter, we estimate natural variables and test their ability to explain the ination process for the eight countries that we consider. We use the traditional Keynesian wage-price spiral and the triangle system approaches to estimate the NAIRU and potential output. In the case of the traditional Keynesian wage-price spiral, the price Phillips curve, which can be specied as a triangle Phillips curve, features backward looking ination expectations and nominal wage ination, the output gap and supply shocks. The nominal wage Phillips curve features ination expectations and price ination and the unemployment gap. The presence of price ination in the nominal wage Phillips curve and the presence of nominal wage ination in the price Phillips curve leads to the interaction between the two Phillips curves. The separate demand pressure terms allows for their identication since, as someauthorsintheliteraturearguethatthegoodsandlabourmarketsdonot move in line with each other. To compute the NAIRU and potential output using the Keynesian approach, we rstly exploit the information contained in vector of unobservable by estimating the wage-price spiral in di⁄erence form using the Seemingly Unrelated Regression method. We use this regression method in order to control for any correlation that may exist between errors in the price and wage Phillips curves. This allows us to solve for the vector of potential output and the NAIRU. We then the moving average technique in order to avoid problems associated with the HP lter for smoothing. Due to data availability, use the MA (20) approximation of the low pass lter after padding the endpoints with forecasts from an AR(4) process. We follow a similar procedure in the estimation of the estimation of the NAIRU and potential output for the triangle system approach. To test which method produces the best natural variables, we t the gaps that are computed from the NAIRU and potential output in a simple single equation price Phillips curve. To test which specication produces the best natural varibles we use a simple single equation triangle price Phillips curve. We nd that the output gaps computed from the two competing approaches are signicantly correlated, the same applies to the unemployment gaps computed from the two approaches. We nd that the quality of unemployment rate gaps computed from the Keynesian and triangle system approach to produce similar quality of results when tted to a single equation triangle price Phillips curve. The Keynesian approach slightly outperforms the triangle systems approach in the when considering the output gap as a proxy for the demand pressure. These results indicate that the wage-price spiral still remains an important tool in the determination of the dynamics ination. In the third chapter, we analyze the relationship between monetary policy and natural variables for Australia, Canada, France, South Korea, South Africa, United Kingdom and the United States. We do this by specifying a relationship between natural rates and the real interest rate. The theoretical relationship between the two variables is positive in the case of the NAIRU and negative through Okuns law in the case of potential output. We regress the natural variable against a constant and the MA(8) of the real interest rate. We nd that the parameter of the real interest rate generally has a correct sign when considering the Keynesian approach computed NAIRUs, with only four being signicant. In the case of the triangle system approach NAIRU, we nd that the real interest rate parameter has a correct sign and signicant four countries. We nd that NAIRUs computed using di⁄erent methodologies can produce a di⁄erent reference point for policy makers. We then introduce hysteresis in the relationship between monetary policy and the NAIRU. We then nd that the interest rate parameter generally has a incorrect sign across the three approaches. The HP ltering approach which we include in our study for comparison purposes produces incorrect correlation for all the countries, while the Keynesian approach negative correlation for seven countries, and the triangle system approach in six countries. In the case of the relationship between monetary policy and potential output, we nd that the real interest rate parameter has an incorrect sign. When introducing hysteresis in the relationship between monetary policy and potential we nd that, unlike in the case of the NAIRU this plays signicant role in the relationship. / XL2018

The phenomenal financial expansion of the last decades has been characterised by an exacerbation of systemic instability and an increase in the frequency of financial crises, culminating in the recent meltdown in the US financial sector. The literature on financial crises has developed concomitantly, but despite a large number of papers written on this subject, economists are still struggling to understand the underlying determinants of these phenomena. In this dissertation, I argue that one of the reasons for this apparent failure is the way agents, as well as the environment in which they evolve, are modelled in this literature. After reviewing the existing literature on international financial crises, I outline an alternative framework, drawing from Post-Keynesian and Behavioural insights. In this framework, international financial crises are seen as being a direct consequence of the way agents formulate expectations in an environment of fundamental uncertainty and the investment and financial decisions they subsequently take. I argue that the psychological heuristics agents use in formulating expectations under fundamental uncertainty can lead to decisions which fragilise the economy and can thus be conducive to financial crises. I then apply this framework to the study of the 2000-2001 financial crisis in Turkey, which is notorious for not lending itself easily to explanations based on the existing theoretical literature on international financial crises. After outlining the crisis and reviewing the main existing accounts, I identify two moments prior to the crisis: A phase of increasing financial fragility, lasting from a previous crisis in 1994 to 1999, and a financial bubble in 2000 during the implementation of an IMF stabilisation program, partly predicated on the previous increase in financial fragility. My framework can account for both periods; it fits particularly well the first one and enhances the explanatory content of existing stories about the events that took place in 2000.

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<p>The aim of this thesis is to provide mathematical tools for an alternative to the mainstream study of macroeconomics with a focus on debt-driven dynamics.</p> <p>We start with a survey of the literature on formalizations of Minsky's Financial Instability Hypothesis in the context of stock-flow consistent models.</p> <p>We then study a family of macro-economical models that date back to the Goodwin model. In particular, we propose a stochastic extension where noise is introduced in the productivity. Besides proving existence and uniqueness of solutions, we show that orbits must loop around a specific point indefinitely.</p> <p>Subsequently, we analyze the Keen model, where private debt is introduced. We demonstrate that there are two key equilibrium points, intuitively denoted good and bad equilibria. Analytical stability analysis is followed by numerical study of the basin of attraction of the good equilibrium.</p> <p>Assuming low interest rate levels, we derive an approximate solution through perturbation techniques, which can be solved analytically. The zero order solution, in particular, is shown to converge to a limit cycle. The first order solution, on the other hand, is shown to explode, rendering its use dubious for long term assessments.</p> <p>Alternatively, we propose an extension of the Keen model that addresses the immediate completion time of investment projects. Using distributed time delays, we verify the existence of the key equilibrium points, good and bad, followed by their stability analysis. Through bifurcation theory, we verify the existence of limit cycles for certain mean completion times, which are absent in the original Keen model.</p> <p>Finally, we examine the Keen model under government intervention, where we introduce a general form for the government policy. Besides performing stability analysis, we prove several results concerning the persistence of both profits and employment. In economical terms, we demonstrate that when the government is responsive enough, total economic meltdowns are avoidable.</p> / Doctor of Philosophy (PhD)

It will be a part of the purpose of this paper to show that Keynesian economics treats a closed economy in a static condition while American and British society in actuality exist in open economies in a dynamic condition. In scope this paper is limited to an appraisal of the first of the main concepts of John Maynard Keynes' General Theory. That is, this paper will be concerned only with the "Theory of the Propensity to Consume" and its ramifications.

No / Using a two-stage quantile regression framework, we uncover significant asymmetries across quantiles for all coefficients in an otherwise standard New Keynesian Phillips Curve (NKPC) for the euro area. A pure NKPC specification accurately captures inflation dynamics at high inflation quantiles.