This dissertation is divided in two sections. The first section addresses the question of the consequences of fiscal policy interventions on the economy and the second section analyzes the issue of the liquidity of European Government bonds during the recent financial crisis, the effect ofliquidity shock on these securities and consequences ofpolicy responses. The frrst chapter studies the impact of a discretionary government spending shock on economic activity and other macroeconomic variables by using an alternative two-step procedure for the identification of the govemment spending shock. The second chapter analyzes the effects of a combination of fiscal and monetary policy shocks on macroeconomic and financial variables using a Time Varying Parameters Factor Augmented VAR (TVP-FA VAR) mode!. The third chapter investigates the European market of repurchase agreements and shows that government bonds represent a key fraction of the collateral in these transactions. lt also examines the effects of a rise in haircuts on the value of govemment bonds and shows that this mechanism may represent a channel in the transmission mechanism of banking and sovereign-debt crises in the periphery of the Eurozone. Following the empirical findings of the third chapter, the last chapter proposes a DSGE model with financial frictions to assess the impact of a negative liquidity shock and the consequences ofunconventional policy.
