The Fund seeks to track the investment results of the Nasdaq-100 ex Top 30 Index, which measures the performance of approximately 70 securities of domestic and international non-financial companies listed on Nasdaq based on market capitalization, as determined by Nasdaq, Inc. The Underlying Index is a subset of the Nasdaq-100 Index and represents securities ranked 31st through 100th in the Parent Index when ranked by market capitalization as determined by Nasdaq. The securities in the Underlying Index are weighted based on the market value of their outstanding shares subject to capping. The Underlying Index is reconstituted and rebalanced quarterly in March, June, September, and December. For capping purposes, at each quarterly rebalance, the weight of any single issuer will not exceed 22.5% of the Underlying Index; and the aggregate weight of issuers with individual weights exceeding 4.5% will not exceed 48% of the Underlying Index. Between rebalances, constituent weights may exceed these constraints due to fluctuations in market value, corporate actions, or other events that change the index composition. As of September 12, 2024, a significant portion of the Underlying Index is represented by securities of companies in the consumer discretionary and technology industries or sectors. The components of the Underlying Index are likely to change over time. BFA uses an indexing approach to try to achieve the Fund's investment objective. Unlike many investment companies, the Fund does not try to beat the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued.