The VanEck Oil Services ETF (OIH) endeavors to replicate, as accurately as possible before accounting for its expenses, the price and yield performance of the MVIS US Listed Oil Services 25 Index (MVOIHTR). This index is specifically designed to track the comprehensive performance of U.S.-listed companies that deliver services to the upstream oil sector, which includes firms involved in oil equipment, various oilfield services, and oil drilling.