IGE holds a portfolio of US-listed natural resources companies that operate in US and Canada. The underlying index includes energy and materials sector excluding the chemicals industry, and steel sub-industry as defined by GICS. Specifically, producers of oil, gas and consumable fuels, providers of energy equipment and services, metals and mining companies, manufacturers of paper and forest products, and producers of construction materials, containers and packaging. The underlying index undergoes semi-annual reconstitution. During quarterly rebalance certain caps are applied: each company has a 10% cap while the aggregate weight of the companies in the underlying index with a weight greater than 4.5% cannot exceed 45%.