ERTH holds a portfolio of companies worldwide that are involved in a more efficient use of limited natural resources specifically, they derive 50% or more of their revenue cumulatively from the following six Environmental Impact themes: alternative energy, energy efficiency, green building, sustainable water, pollution prevention and control, as well as sustainable agriculture. Additionally, companies are screened using ESG controversies, ESG business involvement, and sustainable impact metrics. The fund is rebalanced quarterly. Prior to March 24, 2021, the fund traded under a different name (Invesco Cleantech ETF) and ticker (PZD). It also previously tracked the Cleantech Index, which uses a proprietary selection and tiered equal-weighting model.