The Fund invests in securities comprising the Index. The Index is comprised of companies that (i) generate at least 50 percent of their revenue from rare earths or critical metal mining, production, recycling, processing and/or refining or (ii) engage in projects that have the potential, when developed, to generate 50 percent of revenue from rare earths or critical metal mining, production, recycling, processing and/or refining (Rare Earths and Critical Materials Companies). Rare earths and critical materials are those identified by either: (A) the U.S. Government as: (i) a non-fuel mineral or mineral material essential to the economic and national security of the United States, (ii) the supply chain of which is vulnerable to disruption, and (iii) that serves an essential function in the manufacturing of a product, the absence of which would have significant consequences for the U.S. economy or national security; or (B) Australia, Canada, Japan or the European Union as meeting similar criteria. There are a range of minerals or mineral material groups deemed critical under these criteria. Under normal circumstances, the Fund will invest at least 80 percent of its net assets, plus the amount of any borrowings for investment purposes, in securities of Rare Earths and Critical Materials Companies.