Central banks around the world try to influence economic activity by altering nominal interest rates which will have an effect on the real rate. However, this is only possible as long as interest rates are above zero. The case of Japan showed that monetary policy was helpless as nominal rates approached zero. This Book starts with an overview of monetary policy with the restriction that interest rates can not fall below zero. Then optimal monetary policy in a low inflation environment is treated. This is done by using a New Keynesian model with sticky prices. Therefore the model and the necessary optimality conditions will be derived (this will be done extensively in the appendix). After deriving the optimality conditions it will be shown how optimal monetary policy will be conducted. To evaluate the outcome of monetary policy a welfare function will be derived. It will be shown how the welfare function to evaluate the outcome of monetary policy is derived from the utility function of the household. As a result it will be shown that a price level target is welfare maximizing although most central banks nowadays use an inflation target instead. Reasons for an inflation target will be shown in the discussion of the model. The second part of the book describes the inflation dynamics in the euro area to see what monetary authority shall do to prevent the economy from falling into the vicious circle of deflation. Two wage contracting models that describe inflation dynamics in the euro area reasonably well will be explained, the Fuhrer-Moore und the Taylor contracting. After showing the optimal policy it will be discussed how severe the zero bound in the euro area is and what policy alternatives are left when monetary policy is restricted. Finally the results obtained will be discussed to see the pitfalls of price level targeting. The large appendix provides the complete derivation of the model and the optimality conditions.

Chapter 4.1.1.5, Results from other studies: The graph shows the probability that the zero bound binds when the central bank follows a Taylor rule for different target values for the rate of inflation. Hunton and Laxton used the Japan block of the MULTIMOD model of the IMF for evaluating the frequency of bind under a Taylor rule and different inflation targets. This model is a multi-economy macroeconomic model that the IMF uses for the World Economic Outlook. Black et al. used the Quarterly Projection Model of the Bank of Canada to derive their results (Graph 6: Authors graph). Orphanides and Wieland used a small structural model of the U.S. economy to calculate the possibility that the zero bound binds. Finally Riefschneider and Williams employed the model of the U.S. economy used by the FRB to analyze how severe the zero bound is and how often it will be a constraint for the conduct of monetary policy. They all find that setting a higher target will lower the probability that the zero bound binds substantially. All curves are downward sloped and approach zero quickly. At a target for the rate of inflation of two per cent the chances that the bound binds are nearly zero in the studies of Orphanides and Wieland as well as in the study of Black et al. All these studies assumed that monetary policy follows a Taylor rule. This may not simulate the actual behaviour of a central bank when the zero bound becomes apparent. So the results displayed above may over or understate the actual probability that the bound binds when the central bank uses other instruments than just the short term rate or if the central bank does not follow a Taylor rule (for example when the bound becomes apparent and the central bank may decide to use a pre-emptive strike). The analysis above showed results for the U.S. economy, the Canadian and the Japanese economy. The next subchapters show the distortions the zero bound causes in the euro area. Distortions with a Taylor rule: Since the results of the studies that were presented above imply that the zero bound is a probable constraint for the conduct of monetary policy in a low inflation environment it has to be determined how large these distortions are. To do this a model of the European economy is used to derive the distortions when monetary authority follows a Taylor rule. Inflation distortions: The zero bound leads to somewhat tighter monetary policy compared to what would occur in the absence of the bound. This is the case for inflation targets set close to zero because then the probability that the bound binds is larger. This tighter monetary policy leads to a downward bias in the rate of inflation as the graph below shows. The squares represent the outcome for Taylor style contracts and the diamonds the Fuhrer-Moore contracting (Graph 7). The downward bias is stronger for the Fuhrer-Moore contracting. But as the probability to hit the bound decreases with larger inflation targets the bias decreases too at a larger inflation target. With Taylor contracting the bias is reduced to zero when the target is set to two per cent. However, with Fuhrer-Moore contracting is not even at a target rate of four per cent reduced to zero. The standard deviation of the rate of inflation is higher for Taylor contracting than in the case when the zero bound is not a constraint while the standard deviation with Fuhrer-Moore contracting is reduced. And again at an inflation target of two per cent the change in the standard deviation with Taylor contracting vanishes. Output distortions: As with inflation there is also a downward bias in the mean of output. With the zero bound output falls short of potential output by 0.1 percentage points with Taylor contracting at an inflation target set to zero. When the inflation target is set to two per cent it is almost reduced to zero. The distortions are somewhat stronger for the Fuhrer-Moore contracting specification. With 0.14 percentage points at an inflation target of zero it is not very large. However, it does not return to zero as quickly as under Taylor contracting when the inflation target is lifted. The downward bias occurs due to the tighter monetary policy when policy is constrained by the zero interest rate bound (Graph 8). The standard deviation of output is higher for both wage contracting specifications. But the rise is not significant for Taylor contracting. The graphs above show that the distortions can be lowered by raising the inflation target. With Taylor contracting a two per cent inflation target reduces the distortions almost to zero. With Fuhrer-Moore contracting the inflation target should be raised up to four per cent so that only minor disturbances are left. However, this recommendation is not very helpful for policy makers because inflation itself is costly and causes distortions in the economy which will lower welfare. The full benefits of price stability are achieved at zero inflation when the zero bound is not a constraint. The ECB decided to raise its target for the rate of inflation and the graphs above showed that this will lower the distortions of the bound significantly. But this is done by accepting the cost of higher inflation which have not been considered in the simulations. The main costs are price dispersion which leads to ineffective production. This lowers the level of output and lowers welfare through this.

• Europäische Union

• Geldpolitik

• Geldtheorie

• Nullzinsgrenze

• Inflation

• Deflation

Lars Protze, Diplom Betriebswirt (BA) Studium der Bankbetriebslehre an der Fachhochschule für Wirtschaft Berlin im Fachbereich Berufsakademie, Abschluss 2004 Diplom Volkswirt Studium der Volkswirtschaft und Ökonometrie an der Freien Universität Berlin, Abschluss 2007. Derzeit tätig als Audit Assistant im Bereich Bankenprüfung bei KPMG.