SCHZ holds a varied mix of fixed rate, non-convertible, U.S. dollar denominated bondsit`s one of a handful of ETFs tracking the broad and well-known Bloomberg US Aggregate Index. Its bonds include U.S. Treasurys, government-related and corporate bonds, and mortgage pass-through securities. The bonds must have a minimum of USD 300 million outstanding face value and have one or more years remaining to maturity. The fund generally uses a sampling strategy which means the fund does not hold all of the securities in the index. Instead the fund may hold a subset of securities that generally provide the same risk and return as the index. The index is market cap weighted and rebalanced monthly.