IYH represents the healthcare segment by holding an assortment of the largest pharma, health care and biotech companies in the US. The fund tracks an index of large- and midcap companies in the healthcare sector, which consists of pharmaceuticals, biotechnology, healthcare services and equipment companies. Stocks within IYH are selected and weighted by float-adjusted market-cap. The index caps individual securities at 22.5% and also caps all issuers individually exceeding 4.5% to a maximum of 45% of the fund. Index rebalancing is done on a quarterly basis. Prior to September 20, 2021, the fund tracked the Dow Jones U.S. Health Care Index.