A novel market efficiency index for energy futures and their term structure risk premiums

This paper proposes a novel futures market efficiency index which aggregates the efficiencies of futures contracts across their term structure spanning from one month to 12 months. The index measures the ability for price discovery of a long-term futures contract on its nearby short-term contract consistently across its terms. The index uses a recently developed futures market efficiency test which accounts for heteroscedastic prices and time-varying risk premiums. It simultaneously estimates the term premiums of futures, providing valuable information for the investor. The proposed index is employed to investigate the efficiencies of four major energy commodities, namely, crude oil, natural gas, heating oil, and gasoil during the sample period 1990–2016. Numerical results indicate that the market efficiencies vary across terms and across energy commodities. Gasoil futures traded on the Intercontinental Exchange (ICE) are the most efficient and natural gas futures are the least efficient in prices. The spillover dynamics of market risk information across futures markets are investigated using conditionally heteroscedastic common factors (CHCFs) extracted for each commodity using the estimated term premiums. There exist significant delayed, contemporaneous, and potential information spillovers among term premiums of the energy commodities in our sample. Our findings are robust and they can help investors to optimally diversify their portfolios.