The investment seeks to track the performance of a market-weighted corporate bond index with a long-term dollar-weighted average maturity. The fund employs an indexing investment approach designed to track the performance of the Bloomberg Barclays U.S. 10+ Year Corporate Bond Index. This index includes U.S. dollar-denominated, investment-grade, fixed-rate, taxable securities issued by industrial, utility, and financial companies, with maturities greater than 10 years. Under normal circumstances, at least 80% of the fund's assets will be invested in bonds included in the index.