Thesis advisor: Fabio Ghironi / This dissertation consists of three essays on macroeconomics with frictions and uncertainty shocks. The first essay is "Collateral Constrained Workers' Unemployment". Financial market and labor market are closely interconnected each other in the sense that unemployed workers have difficulty not only in borrowing new loan but also in repaying outstanding loan. In addition, if unemployment entails loss from default and no new loan, credit constrained workers will accept lower wage to avoid the loss from losing job. In this paper, we try to investigate the role of the interaction between financial market and labor market over the business cycle. To do that, we assume credit constrained workers can borrow against their houses and repay outstanding loans only when they are employed. We also introduce labor search and matching framework into our model to consider unemployment and wage bargaining process explicitly. With this setup, we find that adverse housing preference shock leads to substantial negative impact on labor market by reducing the benefit from maintaining job. As a result, high unemployment significantly amplifies the business cycle by reducing supply of loan and increasing default. This result would be helpful to understand recent "Great Recession" which was originated from the collapse of housing market and accompanied by high unemployment and default rate. The second essay is "International Financial Business Cycles". Recent international macroeconomics literature on global imbalances explains the U.S. persistent current account deficit and emerging countries' surplus, i.e., the U.S. is the borrower. Little research has been done on the banking-sector level, where U.S. banks are lenders to banks in emerging countries. We build a two country framework where banks are explicitly modeled to investigate how lending in the banking sector can affect the international macroeconomy during the recent crisis. In steady state, banks in the developing country borrows from the U.S. banks. When the borrowers in the U.S. pay back less than contractually agreed and damage the balance sheet of the U.S. banks, with the presence of bank capital requirement constraint, U.S. banks raise lending rates and decrease the loans made to U.S. borrowers as well as banks in the developing country. The results are a sharp increase in the lending spread, a reduction in output and a depreciation in the real exchange rate of the developing country. They are the experience of many emerging Asian markets following the U.S. financial crisis starting in late 2007. Another feature of our model captures an empirical fact, documented by Devereux and Yetman (2010), that across different economies, countries with lower financial rating can suffer more when the lending country deleverages. The third essay is "Uncertainty, Collateral Constrained Borrowers, and Business Cycle". Standard RBC model fails to generate the co-movement of key macro variables under uncertainty shock because precautionary saving motive decreases consumption but increases investment and labor. To fill this gap, we build a DSGE model with collateral constrained borrowers who can borrow against housing and capital. In the model with modest risk aversion, we can generate the desired co-movement of key macro variables under uncertainty shock and the co-movement comes from the collateral constraint channel through drop in housing price. Under uncertainty shock, highly indebted borrowers sell collaterals to avoid uncertainty in future consumption. As a result, housing price goes down and it makes credit crunch to borrowers through collateral constraint channel. The negative effect of uncertainty shock is strengthened in the economy with higher indebted borrowers. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

<p>In this thesis I explore dimensions through which changes in expectations can serve as a driver of business cycles in a rational expectations setting. Exploiting both the ``sunspot'' and ``news-shock'' approaches to expectations-driven business cycles, I use various theoretical models to investigate how changes in expectations may have played a role in macroeconomic events such as the technological revolution of the 1990's and the financial boom and bust of 2003-2008.</p> <p>In the first chapter, I explore the ability of a model with knowledge capital to generate business cycles driven by expectations of future movement in total factor productivity (TFP). I model knowledge capital as an input into production which is endogenously produced through a learning-by-doing process. When firms receive news of an impending productivity increase, the value of knowledge capital rises, inducing the firm to hire more hours to ``invest'' in knowledge capital. The rise in the value of knowledge capital immediately raises the value of the firm, causing an appreciation in stock prices. If the expected increase in productivity fails to materialize, the model generates a recession as well as a crash in the stock market.</p> <p>In the second chapter, I explore the extent to which expectations about innovations in the financial sector may have contributed to both the boom and bust associated with the ``Great Recession''. Making a connection between the ``boom-years'' of easy credit and the crises of 2008, I argue that agents' overly-optimistic expectations of the benefits associated with financial innovation led to a flood of liquidity in the financial sector, lowering interest rate spreads and facilitating the boom in asset prices and economic activity. When the events of 2007-2009 led to a re-evaluation of the effectiveness of these new products, agents revised their expectations regarding the actual efficiency gains available to the financial sector and this led to a withdrawal of liquidity from the financial system, a reversal in credit spreads and asset prices and a bust in real activity. Following the news-shock approach, I model the boom and bust cycle in terms of an expected future fall in the costs of bankruptcy which are eventually not realized. The build up in liquidity and economic activity in expectation of these efficiency gains is then abruptly reversed when agents' hopes are dashed. The model generates counter-cyclical movement in the spread between lending rates and the risk-free rate which is driven purely by expectations, even in the absence of any exogenous movement in bankruptcy costs as well as an endogenous rise and fall in asset prices and leverage.</p> <p>In the final chapter, I explore the extent to which a ``bout of optimism'' during a period of technological change such as the 1990's could produce not just a boom in consumption, investment and hours-worked, but also rapid growth in productivity itself. I present a theoretical model where the economy endogenously adopts the technological ideas of a slowly evolving technological frontier, and show that the presence of a ``technological gap'' between unadopted ideas and current productivity can lead to multiple equilibria and therefore the possibility that changes in beliefs can be self-fulfilling, often referred to as sunspots. In the model these sunspots take the form of beliefs about the value of adopting the new technological ideas, and unleash both a boom in aggregate quantities as well as eventual productivity growth, increasing the value of adoption and self-confirming the beliefs. In this sense, the model provides an alternative interpretation of the empirical news-based results that identify expectational booms that precede growth in TFP. Finally, I demonstrate that the scope for the indeterminacies is a function of the steady-state growth rate of the underlying frontier of technological ideas, and that during times of low growth in ideas or technological stagnation, the potential for indeterminacies and thus belief-driven productivity growth diminishes.</p> / Doctor of Philosophy (PhD)

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.

[pt] Este artigo objetiva decompor o spread bancário utilizando um modelo macroeconômico estrutural. Nós enriquecemos um arcabouço de equilíbrio geral com empréstimos para indivíduos e firmas que podem inadimplir, um setor bancário em competição monopolística e sujeito a custos administrativos e também acrescentamos uma estrutura de impostos relacionadas a intermediação bancária. Essas características da composição do spread estão em linha com a literatura empírica dos determinantes do spread bancário e com a decomposição contábil do spread realizada pelo Banco Central do Brasil (BCB). Nossa análise quantitativa revela que a redução do spread para indivíduos é maior quando aumentamos a competição no mercado bancário (3.77 p.p. trimestral ou 54 porcento comparado a calibração baseline). Ademais, redução do custo administrativo é a maneira mais eficaz para reduzir o spread para firmas (1.35 p.p. trimestral ou 46 porcento comparado a calibração baseline) e também é capaz de reduzir o spread para indivíduos (2.5 p.p. trimestral ou 36 porcento comparado a calibração baseline). Resultados também sugerem cuidado na formulação de políticas econômicas somente baseadas na decomposição contábil realizada pelo BCB e sem um modelo econômico fundamentando a análise. Esta dissertação também revela alguns desafios relacionados à inclusão da inadimplência juntamente com um mercado bancário em competição imperfeita e sua contribuição para formação do spread. / [en] This paper aims to decompose the banking spread using a structural macroeconomic model. We embedded a general equilibrium framework with loans to households and entrepreneurs that may be in default, a banking sector in monopolistic competition and subject to administrative costs, and we also added a tax structure related to bank intermediation. These characteristics for the composition of the spread are in line with the empirical literature on banking spread determinants in Brazil and with the accounting decomposition of the spread made by the Banco Central do Brasil (BCB). Our quantitative findings reveal that household spread reduction is greater when we increase competition in the banking sector (3.77 p.p. quarterly or 54 percent decrease compared to baseline calibration). Furthermore, reducing administrative cost is the most effective way of diminishing entrepreneur spread (1.35 p.p. quarterly or 46 percent decrease compared to baseline) and it is also capable of diminishing household spread (2.5 p.p. quarterly or 36 percent decrease compared to baseline). Results also suggest some careful actions by policy makers only supported by BCB accounting decomposition without an economic model underpinning the analysis. This dissertation also reveals some challenges regarding the inclusion of credit default with a banking sector in imperfect competition and its contribution to the spread formation.

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