CNRG focuses on US-listed companies whose products and services are driving innovation behind clean power. The underlying index is a combination of two sub-indexes, one that follows the manufacture of technology used in renewable energy, and another that follows companies offering products and services related to renewable energy. The methodology involves scanning company documents and SEC submissions for search terms to determine inclusion in the index. Selected stocks are deemed either core or non-core depending on whether renewable energy is a central focus of the company. Holdings are initially weighted equally, with an overweighting factor applied to core stocks. The index is rebalanced semi-annually.