This D.Phil. dissertation investigates the areas in financial stability. The three comprising essays have a common ground: money, default and collateral in the theory of finance. Chapter Two (co-authored with Prof. Dimitrios Tsomocos), which is titled “A Dynamic General Equilibrium Model to Analyse Financial Stability”, aims to refine and improve existing DSGE models in two ways. First, it incorporates hitherto neglected components such as endogenous default, money via cash-in-advance constraints and heterogeneous banking sectors. Thus, in contrast to the New Keynesian approach, here it is liquidity and default that are the driving forces behind our results. Second, in focusing on both monetary policy and fiscal policy, it elucidates how interactions between the two policy arenas affect macroeconomic fluctuations, particularly in regard to financial stability. Through these refinements, we put forward the policy response necessary to achieve a stable financial system using a calibrated DSGE model. Chapter Three, entitled “Monetary Policy in a Time of Natural Disaster”, investigates the appropriate monetary policy response to natural disasters in the DSGE framework. I develop a realistic model for financial turmoil by evaluating the impact of natural disasters on credit markets by including financial frictions such as endogenous default and liquidity constraints. I show that the standard Taylor rule (1993) response in models with money and default is to increase the nominal interest rate after a disaster shock. However, in fact an inflation-targeting policy (i.e. monetary contraction) is not compatible with mitigating financial fragility in the highly indebted economy with near-zero interest rate, and arguably the `Taylor Principle' does not hold in such as economy (e.g. Japan in 2011). Nevertheless, expansionary monetary policy induces a debt overhang even further. Chapter Four, “Collateral, Default and Asset Prices”, uses a DSGE framework to put forward a model of how agents adjust their asset holdings in response to deflationary shocks. By introducing collateral constraints in the default decision, I capture some original features of the early debt-deflation literature, such as distress selling and instability. The estimated model successfully delivers a procyclical feedback loop for the default channel, which consists of foreclosure, high borrowing costs, inefficient capital allocation, and a further decrease in the output level. I investigated recessionary shocks inducing deflation in commodity and/or asset prices for monetary policy experiments. This, therefore, underlines the importance of monetary policy in restoring financial stability during a deflationary period.

We introduce the tractable buffer stock savings setup of Carroll (2009 NBER Working Paper) into an otherwise conventional New-Keynesian dynamic stochastic general equilibrium model with financial frictions. The introduction of a precautionary saving motive arising from an uninsurable risk of permanent income loss, affects the model's properties in a number of interesting ways: it produces a more hump-shaped reaction of consumption in response to both supply (technology) and demand (monetary) shocks, and more pronounced reactions in response to demand shocks. Adoption of the buffer stock savings setup thus offers a more microfounded way, compared to, e.g., habit preferences in consumption, to introduce Keynesian features into the model, serving as a device to curbing excessive consumption smoothing, and to attributing a higher role to demand driven fluctuations. We also discuss steady state effects, determinacy properties as well as other practical issues. (authors' abstract) / Series: Department of Economics Working Paper Series

This thesis aims at contributing to the existing studies in the dynamic stochastic general equilibrium model, particularly in the new Keynesian models, on three aspects. It consists of three chapters. Chapter 2 is on “Dynamic new Keynesian Life-Cycle Model.” Chapter 3 is on “Re-thinking Price Stability in an Economy with Endogenous Firm Entry: Real Imperfections under Product Variety.” Chapter 4 is on “Growth Expectation.” Abstracts of each Chapter are as follows. In Chapter 2, we first construct a dynamic new Keynesian model that incorporates life-cycle behavior a la Gertler (1999), in order to study whether structural shocks to the economy have asymmetric effects on heterogeneous agents, namely workers and retirees. We also examine whether considerations of life-cycle and demographic structure alter the dynamic properties of the monetary business cycle model, specifically the degree of amplification in impulse responses. According to our simulation results, shocks indeed have asymmetric impacts on different households and the demographic structure does alter the size of responses against shocks by changing the trade-off between substitution and income effects. In Chapter 3, we re-think price stability in an economy with endogenous firm entry under possible distortions. We first demonstrate that endogenous entry causes real imperfections. Reflecting fluctuations in the number of varieties, the gap between the natural and the efficient level of output is no longer constant and variant to shocks. As a result, the central bank faces a trade-off between stabilizing inflation and welfare-relevant output gap. Then, we show that this results in the non-zero optimal rate of inflation. We further check whether welfare can be enhanced by targeting welfare-based inflation instead of cross-sectional average inflation contrary to the previous findings. Simulations even with such distortions as unknown natural interest rate or no fiscal remedy for efficient non-stochastic steady states, however, support cross-sectional average inflation targeting although there may exist some small gains by referring also to welfare-based inflation rates. Incomplete stabilization may enhance welfare in an economy when agents cannot internalize the externality on the love for variety. Chapter 4 is about the difficulty in producing reasonable business cycles for the expectation shock about higher future technology. For a long time, changes in expectations about the future have been thought to be significant sources of economic fluctuations, as argued by Pigou (1926). Although creating such an expectation-driven cycle (the Pigou cycle) in equilibrium business cycle models was considered to be a difficult challenge, as pointed out by Barro and King (1984), recently, several researchers have succeeded in producing the Pigou cycle by balancing the tension between the wealth effect and the substitution effect stemming from the higher expected future productivity. Seminal research by Christiano et al. (2007a) explains the “stock market boom-bust cycles,” characterized by increases in consumption, labor inputs, investment and the stock prices relating to high expected future technology levels, by introducing investment growth adjustment costs, habit formation in consumption, sticky prices and an inflation-targeting central bank. We, however, show that such a cycle is difficult to generate based on “growth expectation,” which reflect expectations of higher productivity growth rates. Thus, Barro and King’s (1984) prediction still applies.

The thesis sheds light on key policy issues emerging from the recent Global Financial Crisis. The first chapter studies whether expansionary monetary policy contributes to bank risk-taking, in the case of Asia. I rely on panel data analysis covering 432 banks in 9 Asian countries over the year 2000-2011. The ratio of risky assets to total assets serves as a risk-taking indicator. The results support the existence of the bank risk-taking channel, which is more pronounced for banks listed on the stock market. I also report new findings with respect to how banks take more risk following monetary expansion. Importantly, evidence of excessive leverage is not found. The second chapter constructs a model for analyzing bank risk-taking. I embed firm heterogeneity, endogenous default risk and capital adequacy regulation into both RBC and NK DSGE models. A subset of the firms can partially default on their loans obligation but subject to non-pecuniary default penalty. With those financial frictions in place, I find that standard macroeconomic shocks can induce banks to engage in higher risk-taking. The chapter then explores the effectiveness of several macro-prudential tools in mitigating risk-taking. I find countercyclical capital buffers and risky to total asset ratio targeting to be effective. The third chapter emphasises the spillover effects of shocks originating in the housing and financial market on the real economy. I embed endogenous mortgage default into a New Keynesian model that features housing and the banking sector. The latter faces capital regulation. We study two key shocks, namely shocks to the variance of idiosyncratic housing shock and shocks to the penalty on capital regulation. Both are instrumental in causing a surge in mortgage default and loans risk premium, which constrains bank lending activity. The chapter later introduces three macroprudential measures to explore whether they improve economic stability and welfare.

Tese (doutorado)—Universidade de Brasília, Faculdade de Economia, Administração e Contabilidade, Programa de Pós-Graduação, 2015. / Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2015-12-21T12:31:38Z No. of bitstreams: 1 2015_MárcioFranciscodaSilva.pdf: 7139934 bytes, checksum: ac253c51aadacb24ce372e5f5ae78f54 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2016-01-12T15:22:12Z (GMT) No. of bitstreams: 1 2015_MárcioFranciscodaSilva.pdf: 7139934 bytes, checksum: ac253c51aadacb24ce372e5f5ae78f54 (MD5) / Made available in DSpace on 2016-01-12T15:22:12Z (GMT). No. of bitstreams: 1 2015_MárcioFranciscodaSilva.pdf: 7139934 bytes, checksum: ac253c51aadacb24ce372e5f5ae78f54 (MD5) / Neste trabalho foram analisadas duas extensões do modelo proposto por (2010). Na primeira versão são introduzidos um setor produtor de imóveis e uma modalidade de empréstimos às famílias impacientes com base no salário esperado. Estas mudanças têm como objetivo mimetizar duas características importantes da economia brasileira: a importância do setor de construção civil e do empréstimo consignado para o ciclo de negócios brasileiro. Na segunda versão do modelo foram incluidas as transações da economia doméstica com o exterior nos setores de bens (importando insumos e exportando bens finais) e financeiro (captação de poupança externa por meio dos bancos). Isto possibilita analisar a importância dos choques externos -a- os choques originados do setor financeiro para a economia brasileira. / This study analyzes two extensions of the model proposed by (2010). In the first one, a housing producing sector was introduced. In addition to that a different form of loans to impatient households is considered that is based on the expected wage of households. When the family takes new loans, her ability of borrowing depends on their expected wage. These changes are intended to mimic two important characteristics of the Brazilian economy: the role of housing sector in the business cycle and the supply of payroll loans. In the second extension of the model, the environment was changed to a small open economy where the transactions of goods (importing raw materials and exporting finished goods) and financial sector (foreign savings funding through banks) to the rest of the world is taken into account. This makes it possible to analyze the importance of external shocks -- the shocks arising from the financial sector to the Brazilian economy.

The objective of this thesis is to develop alternative forms of Dynamic Stochastic General Equilibrium (DSGE) models for forecasting the South African economy and, in turn, compare them with the forecasts generated by the Classical and Bayesian variants of the Vector Autoregression Models (VARs). Such a comparative analysis is aimed at developing a small-scale micro-founded framework that will help in forecasting the key macroeconomic variables of the economy. The thesis consists of three independent papers. The first paper develops a small-scale DSGE model based on Hansen's (1985) indivisible labor Real Business Cycle (RBC) model. The results suggest that, compared to the VARs and the Bayesian VARs, the DSGE model produces large out-of-sample forecast errors. In the basic RBC framework, business cycle fluctuations are purely driven by real technology shocks. This one-shock assumption makes the RBC models stochastically singular. In order to overcome the singularity problem in the RBC model developed in the first paper, the second paper develops a hybrid model (DSGE-VAR), in which the theoretical model is augmented with unobservable errors having a VAR representation. The model is estimated via maximum likelihood technique. The results suggest DSGE-VAR model outperforms the Classical VAR, but not the Bayesian VARs. However, it does indicate that the forecast accuracy can be improved alarmingly by using the estimated version of the DSGE model. The third paper develops a micro-founded New-Keynesian DSGE (NKDSGE) model. The model consists of three equations, an expectational IS curve, a forward-looking version of the Phillips curve, and a Taylor-type monetary policy rule. The results indicate that, besides the usual usage for policy analysis, a small-scale NKDSGE model has a future for forecasting. The NKDSGE model outperforms both the Classical and Bayesian variants of the VARs in forecasting inflation, but not for output growth and the nominal short-term interest rate. However, the differences of the forecast errors are minor. The indicated success of the NKDSGE model for predicting inflation is important, especially in the context of South Africa - an economy targeting inflation. / Thesis (PhD (Economics))--University of Pretoria, 2008. / Economics / unrestricted

In this thesis, I take a theoretical dynamic stochastic general equilibrium (DSGE) approach to investigate optimal aggregate dividend policy. I make the following contribution: 1. I extend the standard DSGE model to incorporate a residual dividend policy, external financing and default and find that simulated optimal aggregate payouts are much more volatile than the observed data when other variables are close to the values observed in the data. 2. I examine the sensitivity of optimal aggregate dividend policy to the level of the representative agent¿s habit motive. My results show that, when the habit motive gets stronger, the volatility of optimal aggregate payouts increases while the volatility of aggregate consumption decreases. This is consistent with the hypothesis that investors use cash payouts from well diversified portfolios to help smooth consumption. 3. I demonstrate that the variability of optimal aggregate payouts is sensitive to capital adjustment costs. My simulated results show that costly frictions from changing the capital base of the firm cause optimal aggregate dividends and real investments to be smooth and share prices to be volatile. This finding is consistent with prior empirical observations. 4. I run simulations that support the hypothesis that optimal aggregate dividend policy is similar when the representative firm is risk averse to when it has capital adjustment costs. In both cases, optimal aggregate dividends volatility is very low. 5. In all calibrated DSGE models, apart from case 4, optimal aggregate payouts are found to be countercyclical. This supports the hypothesis that corporations prefer to hold more free cash flows for potential investment opportunities instead of paying dividends when the economy is booming, but is inconsistent with observed data. Keywords: Dynamic Stochastic General Equilibrium (DSGE), real business cycle, utility function, habits, dividends

The thesis examines the ability of DSGE models with financial elements to explain financial asset prices. A neoclassical macroeconomic model is used, in- cluding a financial constraint in the form of a restriction on external financing. Moreover, the strictness of the restriction is affected by an external financial shock. It is shown, that the combination of the financial constraint and the fi- nancial shock contributes to understanding of the macroeconomic fluctuations, asset price dynamics and their mutual impact. The calibration for the United States demonstrates that the financial shock is an important source of the as- set price volatility. Contrary, when calibrated to the Czech data, the financial shock generates only moderate asset price volatility, as a consequence of a posi- tive correlation with the productivity shock. To address the issue, the model is further extended by a sector of financial intermediaries and a preference shock related to the risk-aversion of economic subjects, and the extension is shown to improve the result.

This work presents a systematic investigation of two topics. One is in stochastic dynamic general equilibrium. It incorporates private information into dynamic general equilibrium framework. An existence of competitive equilibrium is established. Quantitative analysis is provided for health insurance problem. The other topic is in decision problems under ambiguity. Lack of precise information regarding a decision problem is represented by a set of probabilities. Descriptive richness of the set of probabilities is defi ned. It is used to generalize Skorohod's theorem to sets of probabilities. The latter is used to show the constancy of the coefficient in alpha-maximin multiple prior preferences. Examples illustrate: the implications of this representation; and the restrictions arising from the failure of descriptive richness. / text

In this thesis, I take a theoretical dynamic stochastic general equilibrium (DSGE) approach to investigate optimal aggregate dividend policy. I make the following contribution: 1. I extend the standard DSGE model to incorporate a residual dividend policy, external financing and default and find that simulated optimal aggregate payouts are much more volatile than the observed data when other variables are close to the values observed in the data. 2. I examine the sensitivity of optimal aggregate dividend policy to the level of the representative agent's habit motive. My results show that, when the habit motive gets stronger, the volatility of optimal aggregate payouts increases while the volatility of aggregate consumption decreases. This is consistent with the hypothesis that investors use cash payouts from well diversified portfolios to help smooth consumption. 3. I demonstrate that the variability of optimal aggregate payouts is sensitive to capital adjustment costs. My simulated results show that costly frictions from changing the capital base of the firm cause optimal aggregate dividends and real investments to be smooth and share prices to be volatile. This finding is consistent with prior empirical observations. 4. I run simulations that support the hypothesis that optimal aggregate dividend policy is similar when the representative firm is risk averse to when it has capital adjustment costs. In both cases, optimal aggregate dividends volatility is very low. 5. In all calibrated DSGE models, apart from case 4, optimal aggregate payouts are found to be countercyclical. This supports the hypothesis that corporations prefer to hold more free cash flows for potential investment opportunities instead of paying dividends when the economy is booming, but is inconsistent with observed data. Keywords: Dynamic Stochastic General Equilibrium (DSGE), real business cycle, utility function, habits, dividends.