Measuring the effect of the zero lower bound on yields and exchange rates

The zero lower bound on nominal interest rates began to constrain many central banks’ setting of short-term interest rates in late 2008 or early 2009. According to standard macroeconomic models, this should have greatly reduced the effectiveness of monetary policy and increased the efficacy of fiscal policy. However, these models also imply that asset prices and private-sector decisions depend on the entire path of expected future short-term interest rates, not just the current level of the monetary policy rate. Thus, interest rates with a year or more to maturity are arguably more relevant for asset prices and the economy, and it is unclear to what extent those yields have been affected by the zero lower bound. In this paper, we apply the methods of Swanson and Williams (2013) to medium- and longer-term yields and exchange rates in the U.K. and Germany. In particular, we compare the sensitivity of these rates to macroeconomic news during periods when short-term interest rates were very low to that during normal times. We find that: 1) USD/GBP and USD/EUR exchange rates have been essentially unaffected by the zero lower bound, 2) yields on German bunds were essentially unconstrained by the zero bound until late 2012, and 3) yields on U.K. gilts were substantially constrained by the zero lower bound in 2009 and 2012, but were surprisingly responsive to news in 2010–11. We compare these findings to the U.S. and discuss their broader implications.