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Correlation
of % moves
+54%
In sync
of periods
72%
History
daysdays · through 2026-05-22
1,255
These move in the same direction about 72% of the time
Their swing sizes loosely line up (~29% of the pattern is shared).
Strong enough to use as a signal — check the stability and regime notes below before relying on it.
On a log scale so equal % moves take equal vertical space — best when one series has grown much faster than the other.
What to Watch
Unusual right now
Recently tighter than usual — the pair is behaving differently than its long-run pattern.
Holds in both up and down markets
The relationship is similar whether prices are rising or falling — reliable in both directions.
Rock solid
The relationship barely changes from period to period — treat it as a reliable signal.
Advanced
Statistics
In sync(i)
72.4%
Headline metric
Movement correlation(i)
+54%
Based on % moves
95% CI
+50% → +58%
Likely range of correlation
Pipeline
Pipeline Summary
1,255 paired data points survived the daily window.
Raw input
1,255
1,255
Normalized
1,255
1,255
Prepared
1,255
1,255
Aligned
1,255
1,255
Invalid removed
R²(i)
29.1%
Variance explained
Significance
p < 0.001
Statistical confidence
Data points
1,255
Deep
Time-Shifted Correlation
See how correlation changes when one series is offset in time. A taller bar at a non-zero shift means the two move together better when one leads the other — that's a potential lead/lag signal.
Correlation by shift
Click a bar to inspect. Range: -6 to 6 days.
Selected shift
No shift
Correlation at this shift
+54%
No shift — both series at their actual dates.
1,254 overlapping points at this shift
Baseline
+54%
No-shift correlation, matching the main time-series chart above.
Peak shift
No shift
+54%
A non-zero peak suggests one series lines up better when shifted against the other.
Stability
How the correlation evolves over time. A stable line means the relationship is reliable; large swings signal regime-dependent behavior.
Do They Crash Together?
How these series behave when markets are rising, falling, or diverging. A correlation that holds in drawdowns is very different from one that only works in rallies.
Both Rising
+20%
111 periods · Return correlation when both series rose
Both Falling
+22%
96 periods · Return correlation when both series fell
Diverging
-16%
42 periods · Return correlation when series moved apart
Scatter
0
A: 0 / B: 0
Duplicates removed
0
A: 0 / B: 0
Alignment drops
0
A: 0 / B: 0
Series A
WDC
Stock · 1,255 raw → 1,255 prepared
Series B
State Street SPDR S&P 500 ETF Trust (SPY)
SPY
Stock · 1,255 raw → 1,255 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
12
Estimated crossover points between normalized spreads.
Slope
0.1834
Linear regression slope.
Intercept
0.0002
Linear regression intercept.
Saved 3 days ago · ID: stock-spy_stock-wdc_daily_5y