PBD is passively managed to invest in a wide array of global renewable energy companies, including those involved in conservation, improving energy efficiency and advancing renewable energy. The index may invest in large cap firms and those that derives at least 10% of its market value from clean energy activities, but has bias on pure-play, small- and midcap companies. Importantly, PBDs portfolio companies are selected based on the index providers opinion of their potential for capital appreciation. In that sense, PBD is more akin to an actively managed strategy than other funds in the segment. The index is rebalanced and reconstituted quarterly. For diversification, the fund caps its largest holdings at 5% and is required to invest half its assets internationally.