The Invesco Global Clean Energy ETF (PBD) aims to mirror the performance of the WilderHill New Energy Global Innovation Index. This fund typically allocates a minimum of 90% of its total assets to the securities comprising that Index, which can include American Depository Receipts (ADRs) and Global Depository Receipts (GDRs). The underlying Index itself is composed of businesses focused on pioneering advancements in cleaner energy and environmental conservation. Both the ETF's holdings and the benchmark Index undergo adjustments through rebalancing and reconstitution each quarter.