iShares Core Total US Bond Market ETF, formerly iShares Barclays Aggregate Bond Fund (the Fund) seeks investment results that correspond generally to the price and yield performance, of the total United States investment grade bond market as defined by the Barclays Capital U.S. Aggregate Bond Index (the Index). The Index provides a measure of the performance of the United States investment grade bonds market, which includes investment grade the United States Government bonds, investment grade corporate bonds, mortgage pass-through securities and asset-backed securities that are publicly offered for sale in the United States. The securities in the Index must have at least one year remaining to maturity. The Fund generally seeks to track the performance of the Index by investing approximately 90% of its assets in the bonds represented in the Index and in securities that provide substantially similar exposure to securities in the Index.