Barclays Global Investors (BGI) announced in a news release that the fund is designed to track the Lehman Brothers US Aggregate Index, which represents the securities of the US investment grade bond market. iShares currently offers three Treasury ETFs based on Lehman Brothers indices as well as the only US corporate bond ETF.
The Lehman Brothers US Aggregate Bond Index includes publicly issued US Treasury, agency, corporate, mortgage pass-through, asset-backed, and commercial mortgage-backed securities. To be in the index all securities must have at least one year remaining maturity, $150 million par amount outstanding, and be rated investment grade (Baa3 or better) by Moody’s.
iShares are index funds that are bought and sold like common stocks on securities exchanges.