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Correlation
of % moves
+26%
In sync
of periods
59%
History
daysdays · through 2026-05-22
1,252
These move in the same direction about 59% of the time
Their swing sizes only faintly line up (~7% of the pattern is shared).
A real but noisy link — useful as context, risky as a standalone signal.
Both lines start at the same point — easy to compare when growth rates are similar.
What to Watch
Decouples in drawdowns
The relationship weakens when both prices are falling — don't count on this pair as a hedge under stress.
Advanced
Statistics
In sync(i)
59.0%
Headline metric
Movement correlation(i)
+26%
Based on % moves
95% CI
+20% → +31%
Likely range of correlation
Pipeline
Pipeline Summary
1,252 paired data points survived the daily window.
Raw input
1,253
1,252
Normalized
1,253
1,252
Prepared
1,253
1,252
Aligned
1,252
1,252
Invalid removed
R²(i)
6.6%
Variance explained
Significance
p < 0.001
Statistical confidence
Data points
1,252
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
+26%
No shift — both series at their actual dates.
1,251 overlapping points at this shift
Baseline
+26%
No-shift correlation, matching the main time-series chart above.
Peak shift
No shift
+26%
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
-25%
46 periods · Return correlation when both series rose
Both Falling
+0%
53 periods · Return correlation when both series fell
Diverging
-15%
36 periods · Return correlation when series moved apart
Scatter
0
A: 0 / B: 0
Duplicates removed
0
A: 0 / B: 0
Alignment drops
1
A: 1 / B: 0
Series A
BERKSHIRE HATHAWAY Class B (BRK.B)
BRK.B
Stock · 1,253 raw → 1,253 prepared
Series B
Biogen Inc. Common Stock (BIIB)
BIIB
Stock · 1,252 raw → 1,252 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
1
Estimated crossover points between normalized spreads.
Slope
0.5416
Linear regression slope.
Intercept
-0.0005
Linear regression intercept.
Saved 2 weeks ago · ID: stock-biib_stock-brk.b_daily_5y