Strategy. The Fund is diversified and seeks to track the investment results of the Bloomberg US Treasury Ten Year Target Duration Index (the Index). The Index is comprised of certain U.S. Treasury notes and bonds that are included in the Bloomberg US Treasury Index (the Underlying Index). The Index is constructed using two underlying duration buckets of U.S. Treasury notes and bonds included in the Underlying Index that are weighted by market capitalization of their component securities and then blended according to the weighting required to match the 10 year target duration of the Index at the monthly rebalancing date. Securities in the Index and the Underlying Index are updated on the last business day of each calendar month. The Index … Show more… The Fund is diversified and seeks to track the investment results of the Bloomberg US Treasury Ten Year Target Duration Index (the Index). The Index is comprised of certain U.S. Treasury notes and bonds that are included in the Bloomberg US Treasury Index (the Underlying Index). The Index is constructed using two underlying duration buckets of U.S. Treasury notes and bonds included in the Underlying Index that are weighted by market capitalization of their component securities and then blended according to the weighting required to match the 10 year target duration of the Index at the monthly rebalancing date. Securities in the Index and the Underlying Index are updated on the last business day of each calendar month. The Index and the Underlying Index are sponsored by Bloomberg Index Services Limited (the Index Provider), which is not affiliated with the Fund or BIM. The Index Provider determines the composition of the Index and the Underlying Index, relative weightings of the securities in the Index and the Underlying Index and publishes information regarding the respective market value of the Index and the Underlying Index. See More Information About the Funds -- Index Construction for more information about the adjustment formula. There is no limit to the number of issues in the Index and the Underlying Index, but as of December 31, 2025, the Index included approximately 66 constituents, and the Underlying Index included approximately 295 constituents. Because the Index and the Underlying Index are reconstituted and rebalanced monthly, the respective components of the Index and the Underlying Index are likely to change over time. As of December 31, 2025, the securities eligible for inclusion in the Index include U.S. Treasury notes and bonds with durations in the following two duration bucket ranges from the Underlying Index: 6 to 10 year duration securities and 10 to 14 year duration securities. The Underlying Index includes a broad range of U.S. Treasury obligations with a remaining maturity of 1 year or more. For more information regarding the Index and the Underlying Index, see More Information About the Funds Index below. BIM uses a passive or indexing approach to try to achieve the Funds investment objective. Unlike many investment companies, the Fund does not try to outperform the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. Indexing will eliminate the chance that the Fund will substantially outperform the Index but also may reduce some of the risks of active management, such as poor security selection. Indexing seeks to achieve lower costs and better after-tax performance by aiming to keep portfolio turnover low in comparison to actively managed investment companies. BIM uses a representative sampling indexing strategy to manage the Fund. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to that of an applicable target index that BIM determines to collectively have an investment profile similar to that of the Index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and sector weightings), fundamental characteristics (such as return variability, duration, maturity, credit ratings and yield) and liquidity measures similar to those of an applicable underlying index. The Fund may or may not hold all of the securities in the Index. There may be instances in which BIM may choose to underweight or overweight a security in the Index and/or purchase securities not in the Index that BIM believes are appropriate to substitute for certain securities in the Index in seeking to replicate as closely as possible, before fees and expenses, the performance of the Index. The Fund may sell securities that are represented in the Index in anticipation of their removal from the Index or purchase securities not represented in the Index in anticipation of their addition to the Index. Under normal circumstances, the Fund will invest at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in a portfolio of U.S. Treasury securities that collectively have an average duration of approximately 10 years, either directly or indirectly ( e.g. , through derivatives). The Fund may also invest up to 20% of its net assets in certain other U.S. Treasury obligations, U.S. government obligations, U.S. agency securities, cash and cash equivalents, as well as in securities not included in its Index, but which BIM believes will help the Fund track its Index. The Fund seeks to track the investment results ( i.e., the total return) of the Index before fees and expenses of the Fund. The Index is sponsored by the Index Provider, which is independent of the Fund and BIM. The Index Provider determines the composition and relative weightings of the bonds in the Index and publishes information regarding the market value of the Index. Industry Concentration Policy. The Fund will concentrate its investments ( i.e., hold 25% or more of its total assets) in U.S Treasury securities. Show less