The index measures the performance of companies that SPDJI deems to be part of the materials sector of the economy and that SPDJI believes are important to global markets. The fund generally will invest at least 80% of its assets in the component securities of its index and in investments that have economic characteristics that are substantially identical to the component securities of its index and may invest up to 20% of its assets in certain futures, options and swap contracts, cash and cash equivalents.