Asymmetric behavior of inflation differentials in the euro area: Evidence from a threshold unit root test

• This paper examines inflation rate differentials in the eurozone.
• Most of the inflation differentials are characterized by threshold nonlinearity.
• However, there is evidence of unit root regime-switching behavior only in six cases.
• These inflation differentials were persistent in regime 1, but transitory in regime 2.
• The majority of the inflation differentials are found to be monotonically persistent.

This paper tests the existence of persistent inflation rate differentials in the euro area by employing linear as well nonlinear unit root tests. Besides linear unit root tests, a two-regime threshold unit root test examines the conjecture that inflation rate differentials follow a nonlinear two-regime process towards a threshold, switching from the persistent regime to the transitory one and vice versa. The results imply that threshold nonlinearity is confirmed in 10 out of the 16 cases. However, we have found unit root regime-switching behavior only in six out of the 16 cases under investigation. This finding implies that these inflation rate differentials were persistent when they were low (regime 1), but transitory when they were high (regime 2). This asymmetric behavior can possibly be explained by the different degree of pressure exercised on governments, which is accompanied with different inflation rate differentials. On the contrary, despite the evidence of nonlinearity, the majority of the inflation rate differentials are found to be monotonically persistent. Our results have strong implications for policy makers. In particular, the documented persistency in the inflation rate differentials might have long-run costs in terms of price and macroeconomic stability.