The fund is an exchange traded fund (ETF) that aims to track the performance of the Markit iBoxx USD Liquid Investment Grade Ultrashort Index as closely as possible. The ETF invests in physical index securities. The Markit iBoxx USD Liquid Investment Grade Ultrashort Index offers exposure to short maturity corporate bonds (bonds issued by companies) that are denominated in US Dollars and meet a minimum credit-rating of investment grade, as determined by independent credit rating agencies. The index covers fixed rate bonds (bond securities that have a fixed rate of interest) maturing between 0 and 1 year and floating rate securities (bond securities with a variable rate of interest) with a time to maturity between 0 and 3 years. The index uses a market-value weighted methodology with a cap on each issuer of 3%. iShares ETFs are funds managed by BlackRock.