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Correlation Deep Dive

S&P 500 vs Dow Jones: Correlation Analysis

Pearson correlation of daily returns for S&P 500 ETF (SPY) and Dow Jones ETF (DIA). Rolling windows, yearly breakdown, regression beta, and divergence analysis. Data window spans to (1,275 aligned observations).

30-Day
+0.808
Very strong positive
90-Day
+0.890
Very strong positive
1-Year
+0.857
Very strong positive
5-Year
+0.919
Very strong positive

What the Number Means

With a correlation of 0.89, S&P 500 ETF (SPY) and Dow Jones ETF (DIA) move together with remarkable consistency. A daily move in one is a reliable predictor of the direction of the other. This tight coupling usually reflects a common driver or a direct mechanical relationship.

Recent vs Long-Run Behavior

Last 90 Days
+0.890
5-Year Baseline
+0.919

Recent correlation tracks the long-run relationship closely. No meaningful divergence. The historical pattern between S&P 500 ETF (SPY) and Dow Jones ETF (DIA) is intact and should continue to serve as a reasonable baseline for positioning.

Statistical Details (1-Year Window)

Pearson Correlation (r)+0.857
R-Squared (r²)0.734
Beta (S&P 500 ETF (SPY) vs Dow Jones ETF (DIA))0.870
Daily Volatility σ(S&P 500 ETF (SPY))0.78%
Daily Volatility σ(Dow Jones ETF (DIA))0.77%
Observations252

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 Dow Jones ETF (DIA) returns. A beta above 1 means the first asset amplifies moves of the second.

Year-by-Year Correlation

YearCorrelationStrengthObservations
2026+0.875Very strong positive136
2025+0.925Very strong positive250
2024+0.819Very strong positive252
2023+0.897Very strong positive250
2022+0.966Very strong positive251
2021+0.923Very strong positive136

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

Most Correlated Period
+0.982
ending 2022-10-04
Most Decoupled Period
+0.684
ending 2024-07-31

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 Dow Jones ETF (DIA), 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.