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Correlation Deep Dive

Chicago NFCI vs S&P 500: Correlation Analysis

Pearson correlation of daily returns for Financial Conditions (NFCI) and S&P 500 ETF (SPY). Rolling windows, yearly breakdown, regression beta, and divergence analysis. Data window spans to (252 aligned observations).

30-Day
-0.630
Strong negative
90-Day
-0.454
Moderate negative
1-Year
-0.328
Weak negative
5-Year
-0.328
Weak negative

What the Number Means

The -0.45 correlation indicates that Financial Conditions (NFCI) and S&P 500 ETF (SPY) 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

Last 90 Days
-0.454
5-Year Baseline
-0.328

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

Statistical Details (1-Year Window)

Pearson Correlation (r)-0.328
R-Squared (r²)0.108
Beta (Financial Conditions (NFCI) vs S&P 500 ETF (SPY))-0.643
Daily Volatility σ(Financial Conditions (NFCI))4.49%
Daily Volatility σ(S&P 500 ETF (SPY))2.29%
Observations252

Correlation measures directional co-movement; R² quantifies the fraction of variance explained by the linear relationship. Beta is the slope coefficient from regressing Financial Conditions (NFCI) returns on S&P 500 ETF (SPY) returns. A beta above 1 means the first asset amplifies moves of the second.

Year-by-Year Correlation

YearCorrelationStrengthObservations
2026-0.776Strong negative16
2025-0.395Weak negative50
2024-0.183Essentially uncorrelated51
2023-0.239Weak negative51
2022-0.377Weak negative51
2021-0.076Essentially uncorrelated33

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
-0.043
ending 2024-12-13
Most Decoupled Period
-0.454
ending 2026-04-24

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 Financial Conditions (NFCI) and S&P 500 ETF (SPY), 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.