The Fund normally invests at least 80 percent of its total assets in securities that comprise the Funds benchmark index. The Biotech Index includes common stocks and depositary receipts of U.S. exchange-listed companies in the biotechnology industry. Such companies may include medium-capitalization companies and foreign companies that are listed on a U.S. exchange. To be initially eligible for the Biotech Index, companies must generate at least 50 percent of their revenues from biotechnology. Biotechnology includes companies engaged primarily in research (including research contractors) and development as well as production, marketing and sales of drugs based on genetic analysis and diagnostic equipment (excluding pharmacies). Of the largest 50 stocks in the biotechnology industry by full market capitalization, the top 25 by free-float market capitalization (i.e., includes only shares that are readily available for trading in the market) and three-month average daily trading volume are included in the Biotech Index.