In this thesis we develop three essays on Macro-Finance. On the first one, we show that, in Brazil, short run inflation surprises had a significant effect in medium run inflation expectation. This phenomenon leads to a less effective monetary policy, as its output cost is higher. This can be a symptom of at least one of two problems: (i) Inflation inertia due to indexation of the economy; and/or (ii) lack of credibility of the monetary authority. As our model suggests, looking at co-movements of inflation risk premium and inflation surprises helps to identify if lack of credibility is one of the causes. By doing so, we confirm that this was the case in Brazil until very recently. On the second essay, we argue that the current account problem can be understood as the choice of where to allocate national savings: at home or abroad. Moreover, the data reveals that portfolio rebalance is indeed important. For this reason, we develop a current account model in which the representative agent´s portfolio choice problem with time- varying investment opportunities. Thus, we are able to generate rebalancing in portfolios that in turn affects the current account. We estimate/solve this model using a long time series data from different assets in the US and Japan and empirical results indicate that variations in investment opportunities can explain at least 54% of its movements, a performance superior to previous models. The third and last essay studies one important source of financial vulnerability for emerging economies: the positive correlation between country and currency risks. This harmful relation observed in some countries is called cousin risks. We, first, identify the extent of this phenomenon by separating a sample of countries into two groups: the one where the positive correlation is observed and the one where it is not. Based on this taxonomy, we investigate the determinants of the cousin risks. Results indicate that currency mismatch and low financial deepening are strongly associated with the phenomenon.