Abstract

We present a five-year revision of an empirical study started in 2007. Seven years ago, we found three distinct periods characterized by sustainable linear trends in the difference between the headline consumer price index (CPI) and the core CPI in the USA. Then we revealed similar behavior in the differences between the CPI and indices of various consumer expenditure categories. We estimated the duration of these trends which varies in a wide range from 5 years to more than 20 years. The transition periods to new trends span shorter intervals of 2 to 5 years. The transition is characterized by a higher level of volatility in the studied CPI differences.

In April 2009, we introduced a simple quantitative model representing the evolution of motor fuel price (a subcategory of the consumer price index of transportation) relative to the core CPI as a linear function of time. Under our framework, all price deviations from this linear trend are transient and the price must return to the sustainable trend. The model predicted that oil price would fall to $30-$60 per barrel in 2016, which is very close to the current price.

The behavior of actual oil and motor fuel price since 2010 has shown that this prediction is accurate in both amplitude and trajectory shape – a good support for the credibility of our empirical model. We conclude that the concept of price decomposition into a short-term (oscillating) and long-term (linear trend) components deserves a deeper theoretical consideration of the driving forces behind linear time trends and can be used as a workhorse for a wide spectrum of commodity investors.

According to the model, the price of crude oil will be falling to the level of $30 per barrel during the next 6 years and motor fuel will follow up the oil price. Moreover, the periodicity of the related normalized difference indicates that this low-price level may extend into the second half of the 2020s. The secular fall in energy prices may induce a lengthy period of very low inflation.