The fund generally will invest at least 90% of its total assets in the securities that comprise the underlying index. The index is composed of stocks of publicly traded companies listed on a major exchange in the U.S. that are engaged in the business of the advancement of cleaner energy and conservation or are important to the development of clean energy. Stocks are included in the index based on the index provider's evaluation that such companies will substantially benefit from a societal transition toward the use of cleaner energy, zero-CO2 renewables and conservation.