S&P 500 vs 10Y Treasury Yield: Correlation Analysis
Pearson correlation of daily returns for S&P 500 ETF (SPY) and 10Y Treasury Yield. Rolling windows, yearly breakdown, regression beta, and divergence analysis. Data window spans to (1,242 aligned observations).
What the Number Means
The -0.41 correlation indicates that S&P 500 ETF (SPY) and 10Y Treasury Yield have a moderate tendency to move in opposite directions. The relationship is real but noisy, with frequent days where they disagree. Regime context matters: the correlation often strengthens during stress and weakens during calm periods.
Recent vs Long-Run Behavior
The correlation has weakened materially. The 90-day reading of -0.41 sits 0.39 below the long-run average of -0.01. Falling correlation signals the dispersion regime where idiosyncratic stories dominate and cross-asset diversification benefits improve.
Statistical Details (1-Year Window)
| Pearson Correlation (r) | -0.208 |
| R-Squared (r²) | 0.043 |
| Beta (S&P 500 ETF (SPY) vs 10Y Treasury Yield) | -0.171 |
| Daily Volatility σ(S&P 500 ETF (SPY)) | 0.79% |
| Daily Volatility σ(10Y Treasury Yield) | 0.96% |
| Observations | 252 |
Correlation measures directional co-movement; R² quantifies the fraction of variance explained by the linear relationship. Beta is the slope coefficient from regressing S&P 500 ETF (SPY) returns on 10Y Treasury Yield returns. A beta above 1 means the first asset amplifies moves of the second.
Year-by-Year Correlation
| Year | Correlation | Strength | Observations |
|---|---|---|---|
| 2026 | -0.405 | Moderate negative | 111 |
| 2025 | +0.134 | Essentially uncorrelated | 248 |
| 2024 | -0.058 | Essentially uncorrelated | 250 |
| 2023 | -0.039 | Essentially uncorrelated | 249 |
| 2022 | -0.118 | Essentially uncorrelated | 249 |
| 2021 | +0.378 | Weak positive | 135 |
Year-by-year correlation reveals how the relationship has held up across different macro regimes. Sharp year-over-year swings in correlation often mark the transition between stress and calm periods.
Rolling 90-Day Extremes
Extremes in rolling 90-day correlation often coincide with regime changes, forced deleveraging, or the arrival of a dominant new macro theme that overwhelms normal relationships.
Methodology
Correlations are computed on daily log-adjacent returns for S&P 500 ETF (SPY) and 10Y Treasury Yield, aligned on shared trading dates. We use the Pearson product-moment coefficient, which measures the linear relationship between two return series.
Windows are the most recent N observations for 30D, 90D, and 1Y (252 trading days); the 5Y figure uses all aligned data up to 1,260 observations. Beta is the OLS slope from regressing the first series on the second. Data updates daily with a 24-hour revalidation cadence.
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Get daily macro analysis on shifting correlations, regime transitions, and cross-asset signals.
Correlation is not causation and backward-looking statistics can fail when regimes shift. Positions sized on historical correlation assumptions should be stress-tested against scenarios where the relationship breaks. For informational purposes only.