WNDY is one of the few ETFs that capture the global wind energy industry. The fund includes companies engaged in: wind energy systems, wind power production, wind energy technology, and wind power integration & maintenance. Eligible firms are initially scored and ranked based on a proprietary natural language processing algorithm which identifies wind energy companies using keywords from publicly available information. Identified companies are then classified as either pure-play or pre-revenue, and are further screened for compliance with UN Global Compact principles. The fund aims to hold 50 pure-play companies. If fewer than 25 pure-play companies qualify for inclusion, pre-revenue firms will be selected until the portfolio reaches 25 constituents. Holdings are market-cap-weighted with single security weights capped at 12%for pure-plays and 2% for pre-revenue firms. In addition, the aggregate weight of pre-revenue firms cannot exceed 10%. The index rebalances semi-annually.