All other energy commodities increased in price over the past year, notably RBOB (reformulated blendstock for oxygenate blending), heating oil, and gasoil rose by 28 percent, 19 percent, and 19 percent, respectively.
Price changes for each commodity are weighted by their relative importance in the broader market. WTI and Brent crude oil prices accounted for 72% of the weighting in the S&P GSCI energy index and 45 percent of the total GSCI in 2019. Since the creation of the index, WTI and Brent have been the GSCI’s highest and second-highest weighted commodities, respectively, so both the GSCI and the energy sub-index tend to follow major price movements of these crude oils.
Prices of many nonenergy commodities tend to move in the same direction as energy commodities. For instance, because consumers use more copper and more crude oil when the economy is expanding, copper prices and the Brent crude oil price typically move together.
Conversely, precious metals such as gold and silver are typically seen as safe assets with values that increase with economic contractions. Gold and silver prices are positively correlated with each other but negatively correlated with commodities associated with economic expansion.