iShares Core US Aggregate Bond ETF | AGG |



by Zachary Evens

IShares Core US Aggregate Bond’s steady portfolio makes its cheapest share classes attractive. The fund tracks the Bloomberg US Aggregate Bond Index, which includes taxable, investment-grade US bonds with at least one year remaining until maturity. Its final portfolio is market-value weighted, which emphasizes the most liquid issues and harnesses the market’s collective wisdom on the relative value of each bond. The portfolio is shaped by the issuing activity of the US investment-grade market, which is heavily influenced by the US Treasury. Treasury securities now claim more than 45% of the portfolio after increasing their share of the total bond market in recent years. The average rival in the category also owns more Treasuries than it used to, but it still has far less in Treasuries—typically less than 30%—than this portfolio does. Competitors own more securitized fare to make up the difference. The big government bond stake, however, mutes credit risk. About 75% of fund assets are in securities with AA or AAA credit ratings, several percentage points higher than the average Morningstar Category peer. Unlike some peers, the fund cannot hold sub-investment-grade debt. Omitting high-yield bonds and focusing on ultrasafe government securities may restrict the fund’s return or yield potential, yet it also should insulate it from the volatility of riskier bonds. This fund won’t always be less volatile than its average peer, though. It has a longer average effective duration, a measure of interest-rate sensitivity, so rate changes can whip it around. Indeed, in the 10 years ending in February, the US exchange-traded fund version of this strategy was more volatile than its average peer, as measured by standard deviation. |
Morningstar Pillars | |
Pessoas | Above Average |
Parent | Above Average |
Processo | Above Average |