The investment seeks to track the investment results of the S&P California AMT-Free Municipal Bond IndexTM. The index measures the performance of the investment-grade segment of tax-exempt bonds issued within the California municipal bond market. The fund generally will invest at least 90% of its assets in the component securities of the index and may invest up to 10% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates, as well as in securities not included in the index, but which BFA believes will help the fund track the index. It is non-diversified.