AGG vs SPY: Correlation
iShares Core US Aggregate Bond ETF (AGG) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.18.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are AGG and SPY?
Across a 3-year window, the weekly returns of AGG and SPY correlate at 0.18, weak. The past 12 months show a tighter link (0.34) than the 3-year average (0.18). Stretching to 5 years gives 0.27, with an annualized covariance of 14.0 %².
By 3-year correlation, SPY places #21 of the 34 assets tracked against AGG. Their recent paths diverged sharply: over the last 12 months SPY outperformed by 18.3 percentage points (+2.3% for AGG against +20.6% for SPY). This link changes with the market regime, having swung between -0.30 and 0.60 on a rolling one-year basis. One caveat on sizing: SPY is 2.7 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
How is this computed?
Pearson correlation on weekly returns: ρ(A,B) = cov(rA, rB) / (σA · σB), over windows of 52, 156 and 260 weeks. Covariance is annualized (×52) and expressed in %². Full definitions on the methodology page.
AGG vs SPY: side by side
| AGG (iShares Core US Aggregate Bond ETF) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +2.3% | +20.6% |
| 5-year return | -1.1% | +82.4% |
| Volatility (ann.) | 5.3% | 14.5% |
| Beta vs S&P 500 | 0.07 | 1.00 |
| Max drawdown (3Y) | -4.8% | -18.8% |
| Dividend yield | 4.05% | 1.01% |
| Expense ratio | 0.03% | 0.09% |
| Assets under management | $137.1B | $795.3B |
| Sector / category | ETF · Bonds | ETF · US Large Cap |
AGG, iShares's Intermediate Core Bond fund, carries $137.1B under management, a 0.03% expense ratio, a 4.05% trailing dividend yield. SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | AGG | SPY |
|---|---|---|
| 2022 | -13.0% | -18.2% |
| 2023 | +5.7% | +26.2% |
| 2024 | +1.3% | +24.9% |
| 2025 | +7.2% | +17.7% |
| 2026 | +0.3% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are AGG and SPY good diversifiers for each other?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
FAQ
What is the correlation between AGG and SPY?
The AGG/SPY correlation stands at 0.18 on a 3-year window (1 year: 0.34, 5 years: 0.27), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for AGG?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
What does a correlation of 0.18 mean?
A reading of 0.18 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Hubs: AGG correlations · SPY correlations
