RAYS tracks an index of companies involved in the solar energy industry. This includes companies involved in solar power production, the integration of solar into energy systems, and the development/manufacturing of solar-powered technologies. Securities are selected based on a proprietary natural language processing algorithm that identify and rank companies based on filings, disclosures and other public information. Highest-ranking companies are further reviewed to confirm that at least 50% of their revenues are derived from the foregoing activities. The index also applies an ESG screening process to exclude those that does not meet the labor, human rights, environmental, and anticorruption standards. The index is market-cap weighted, subject to 8% single security cap, and is reconstituted and re-weighted semi-annually.