November inflation was very strong. Measured using the Consumer Price Index (CPI) or Harmonised Index of Consumer Prices (HICP), headline inflation rose to 6.8% year-on-year (yoy) in the US and 4.9% yoy in the eurozone, values not seen in the US since the early 1980s and which have never been recorded in the eurozone since its inception in 1999. Excluding food and energy prices, core inflation rose to 4.9% yoy in the US and to 2.6% yoy in the eurozone. Many commentators believe that unexpectedly high inflation will lead central banks to tighten monetary policy faster than previously expected.
However, monetary policy affects inflation with long and variable lags and a policy tightening in the coming months would not have much effect before the end of 2022. It is therefore important to have a view on how inflation will evolve in the coming months: if it were expected to fall significantly, there would be little need for a strong central bank reaction.
The energy component of the November CPI was 33.3% higher than a year before in the US and 27.4% higher in the eurozone. Although energy accounts for only 6% of household consumption in the US and 9% in the eurozone, the increase in energy prices is directly responsible for 30% of total inflation in the US and almost 55% in the eurozone.1 The development of energy prices will therefore be key in determining whether current high inflation rates are temporary and how quickly they will return to more normal values.
The evolution of the energy CPI can be estimated by exploiting the correlation with oil and natural gas prices.2 Statistical analysis suggests that oil prices have been responsible for most of the variation in CPI energy since 2006. Natural gas helps explain energy prices only in the eurozone, but its impact there is 80% less than that of Brent.
The forecasting power of the models can be assessed by stopping the estimation in December 2020 and comparing the model projections to the end of November 2021 with the official data. Charts 1a and 1b show the annual changes of CPI energy in the US and the eurozone, the in-sample projections of the models and the 67% confidence intervals. Given the actual evolution of oil and natural gas prices, both models would have correctly projected a strong increase in the energy CPI, although they underestimate the November data by about 15%.3