The investment seeks to track the performance of a market-weighted government bond index with a long-term dollar-weighted average maturity. The fund employs an indexing investment approach designed to track the performance of the Barclays U.S. Long Government Float Adjusted Index. This index includes fixed income securities issued by the U.S. Treasury (not including inflation-protected bonds) and U.S. government agencies and instrumentalities, as well as corporate or dollar-denominated foreign debt guaranteed by the U.S. government, with maturities greater than 10 years. At least 80% of the fund's assets will be invested in bonds included in the index.