AGG is the bond market equivalent of SPY — the default, institutional-standard fund representing the US investment grade bond market. It tracks the Bloomberg US Aggregate Bond Index, which is the benchmark used by the vast majority of fixed income managers globally, making AGG the reference against which bond portfolio performance is measured. The portfolio holds US Treasuries (roughly 40%), mortgage-backed securities (around 25%) and investment grade corporate bonds (around 25%), with the remainder in agency and other government-related bonds. At 0.03% expense ratio, it is essentially free to own. Duration is approximately 6 years, meaning moderate but meaningful interest rate sensitivity. AGG serves its core portfolio role of providing diversification against equity risk — in most recessions, as equities fall and the Fed cuts rates, AGG appreciates, cushioning overall portfolio losses. The 2022 experience — when both stocks and bonds fell simultaneously due to aggressive rate hikes — illustrated that this diversification is not guaranteed when inflation forces the Fed to tighten aggressively. For investors, AGG remains the standard core fixed income allocation for balanced portfolios, appropriate as a stabilizing position that provides income, reduces overall volatility and diversifies against equity risk in most market environments.
