The main objective of this thesis is to offer empirical evidence in support of the hypothesis that differences in firms' balance sheet structures may generate heterogeneous responses to monetary policy innovations. To this end in the second, introductory, chapter we start providing some evidence in favor of a large degree of heterogeneity in the asset and liability side of the balance sheet structure of manufacturing firms belonging to different European countries and different size classes. This static comparison is complemented with a quantitative assessment of the sensitivity of asset and liability items to business cycle conditions.In the third chapter we focus on a specific dimension along which the presence of heterogeneities in the balance sheet structure may induce different responses to a monetary policy action. In particular we address the existence of a channel of transmission of monetary policy, the cost-channel, that operates through the effect of interest expenses on the marginal cost of production. Such a channel is based on an active role of net working capital (inventories, plus trade receivables, less trade payables) in the production process and on the fact that variations in interest rate and credit conditions alter firms' short-run ability to produce final output by investing in net working capital. It has been argued that this mechanism may explain the dimension of the real effects of monetary policy, give a rationale for the positive short-run response of prices to rate increases (the "price puzzle") and call for a more gradual monetary policy response to shocks. The analysis is based on a unique panel, that includes about 2,000 Italian manufacturing firms and 14 years of data on individual prices and interest rates paid on several types of debt. We find robust evidence in favor of the presence of a cost-channel of monetary policy transmission, proportional to the amount of working capital held by each firm and with a size large enough to have non-trivial monetary policy implications. The empirical analysis of chapter three is based on the hypothesis that the type of heterogeneity that produces different firm level responses to an interest rate variation is well defined and measurable. On the contrary, most of the empirical literature that tests for the existence of heterogeneous effects of monetary policy on firms' production or investment choices is based on an ad hoc assumption of the specific firm level characteristic that should distinguish more sensitive from less sensitive firms. A similar degree of arbitrariness is adopted in selecting the number of classes of firms characterized by different responses to monetary policy shocks as well as in the selection of the cutoff points. The objective of chapter four is to apply a recent econometric methodology that building on data predictive density provides a well defined criteria to detect both the "optimal" dimension along which analyze firms' responses to monetary policy innovations and the "optimal" endogenous groups. The empirical analysis is focused on Italian manufacturing firms and, in particular, on the response of inventory investment to monetary policy shocks from 1983 to 1998. The main results are the following. In strike contrast with what is normally assumed in the literature in most of the cases it turns out that the optimal number of classes that is larger than two. Moreover orderings that are based on variables that are normally thought to be equivalent proxies for the size of the firm (i.e. turnover, total assets and level of employment) do not lead neither to the same number of groups nor to similar splitting points. Finally even if endogenous clusters are mainly characterized by different degrees of within group heterogeneity, with groups composed by smaller firms showing the largest dispersion, there also exist important differences in the average effect of monetary policy across groups. In particular the fact that some of the orderings do not show the expected monotonicity between the rank and the average effect appears to be one of the most remarkable aspects.

In letteratura si assume generalmente che gli agenti siano dotati di perfetta razionalità e quindi siano in grado di anticipare l'evoluzione del sistema economico. Partendo dalla letteratura sull'apprendimento adattivo, si ipotizza che gli agenti si comportino come econometrici, aggiustando le proprie previsioni mano a mano che i dati diventano disponibili. Il primo capitolo analizza l'apprendimento dell'equilibrio da parte degli agenti in presenza di un meccanismo di trasmissione del cost channel. Supponendo che la Banca Centrale operi in regime discrezionale, si osserva che una politica monetaria che risponde all'aspettative garantisce la determinatezza dell'economia solo se la banca centrale dimostra una minor preferenza per la stabilizzazione dell'output. Tuttavia, l'area di determinatezza dell'equilibrio si allarga se la banca centrale stabilizza anche il tasso di interesse. La seconda parte della tesi si concentra invece sul ruolo della stabilità finanziaria nella conduzione della politica monetaria. Sei nei modelli standard di tipo Keynesiano rispondere agli asset prices sortisce degli effetti positivi solo se gli agenti stimano il modello corretto dell'economia, ecco che in presenza di mal specificazione o eterogeneità la banca centrale riesce a raggiungere la stabilità economica attraverso i normali canali. La conclusione si ribalta se il meccanismo di cost channel opera nell'economia. / In the literature agents are endowed by full rationality and hence they are able to anticipate the evolution of the economy. On the findings of the adaptive learning literature, we assume that agents behave as econometricians updating their own forecasts by the available data. In the first essays we analyze the learnability of the equilibrium by agents when the cost channel mechanisms of monetary policy is operating. Under discretion the expectations-based interest rate rule leads the economy to determinacy of the rational expectations equilibrium (REE), only if the degree of preference for economic stability is sufficiently low. On the other hand, the determinacy of REE enlarges if the central bank stabilizes also the interest rate. The second part of the thesis concerns on the role of financial stability in the conducting of monetary policy. If in the standard New Keynesian model responding to asset prices shows benefits for the economy, the presence of misspecification and heterogeneity leads the economy to indeterminacy and E-instability. In an economy characterized by wealth effect and cost channel we show that the optimal discretionary monetary policy drive the economy toward the asymptotic convergence of the economy to the fundamental REE.

[pt] Esta tese é composta de três ensaios. Os dois primeiros investigam a relação entre a potência da política monetária e a prevalência do crédito direcionado (concedido à taxas de juros insensíveis ao ciclo monetário) na economia. O primeiro mostra que a evidência microeconométrica disponível não é necessariamente informativa sobre o fenômeno macroeconômico de interessee ilustra esse resultado com um modelo Novo-Keynesiano simples com financiamento de capital de giro. Dando sequência, o segundo ensaio estende a análise usando um modelo DSGE de médio porte no qual crédito direcionado é utilizado pelas firmas para financiar a aquisição de capital. O modelo é estimado para o Brasil usando técnicas Bayesianas. Sob a distribuição priori mostra-se que a presença de crédito direcionado não reduz necessariamente a potência da política monetária sobre a inflação. Sob a distribuição posteriori mostra-se que a redução de potência é provável, mas pequena. Finalmente, o terceiro ensaio estuda em que medida o efeito de fluxos de capitais sobre o ciclo de negócios depende do tipo do influxo (e.g., se para títulos ou para ações, se um fluxo de ativo ou de passivo), construindo para tanto um modelo Novo-Keynesiano de economia aberta com fricções financeiras. Identifica-se mecanismos diretos através dos quais o influxo pode ter efeito diferenciado dependendo do seu tipo. Conclui-se, usando uma versão calibrada do modelo, que as diferenças são provavelmente pouco significativas. / [en] This thesis is comprised of three essays. The first two investigate the relationship between monetary policy power and the prevalence of earmarked credit (featuring interest rates that are insensitive to the monetary cycle) in the economy. The first shows that the available microeconometric evidence is not necessarily informative about the macroeconomic phenomenon of interest, and illustrates this result with a simples New-Keynesian model with working capital credit. Giving sequence, the second essay extends the analysis with a medium-sized DSGE model where earmarked credit is used to finance the acquisition of physical capital by firms. The model is estimated to Brazil using Bayesian techniques. Under the prior distribution it is shown that the presence of earmarked credit does not necessarily reduces monetary policy power over inflation. Under the posterior it is shown that a reduction of power is likely, but small. Finally, the third essay studies to what extent the effects of capital flows on a small open economy s business cycle depend on the type of the inflow (e.g., whether a bond or a stock inflow, a liability or an asset flow), and for such it build an open economy New-Keynesian model with financial frictions. Direct mechanisms through which inflows may have differentiated effects depending or their type are identified. Using a calibrated version of the model it concludes that the differences are probably of little significance.