Correlation Analysis
BERKSHIRE HATHAWAY Class B vs General Motors Company
BRK.B vs GM
+0.450
Moderate positive
When one moves up, the other tends to follow.
BERKSHIRE HATHAWAY Class B
↗BRK.B
Berkshire Hathaway is a holding company with a wide array of subsidiaries engaged in diverse activities. The firm's core business segment is insurance, run primarily through Geico, Berkshire Hathaway Reinsurance Group, and Berkshire Hathaway Primary Group. Berkshire has used the excess cash thrown off from its operations to acquire Burlington Northern Santa Fe (railroad), Berkshire Hathaway Energy (utilities and energy distributors), and the companies that make up its manufacturing, service, and retailing operations (which include Precision Castparts, Lubrizol, Clayton Homes, Marmon, and IMC/ISCAR). The conglomerate is unique in that it is run on a completely decentralized basis. Berkshire is expected to generate close to $375 billion in revenue in 2025.
Market cap 1T
General Motors Company
↗GM
General Motors Co. emerged from the bankruptcy of General Motors Corp. (old GM) in July 2009. GM has eight brands and operates under three segments: GM North America, GM International, and GM Financial. The United States now has four brands instead of eight under old GM. The company regained its US market share leadership in 2022, after losing it to Toyota due to the chip shortage in 2021. 2025 US share was 17.4%, up 60 basis points from 2024. The Cruise autonomous vehicle arm, which GM now owns outright, previously operated driverless geofenced AV robotaxi services in San Francisco and other cities, but after a 2023 accident, GM decided that it will focus on personal AVs. GM Financial became the company's captive finance arm in 2010 via the purchase of AmeriCredit.
Market cap 66.4B · 156,000 employees
Time Series
Relative Performance
Who Moves First
BRK.B leads GM by 6 days
BRK.B tends to move before GM.
After testing 13 timing shifts, the strongest relationship was +0.458 (they moved in the same direction).
Do They Crash Together?
Correlation by Market Regime
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
+0.007
11 periods · Return correlation when both series rose
Both Falling
-0.216
9 periods · Return correlation when both series fell
Diverging
-0.779
15 periods · Return correlation when series moved apart
R-Squared
20.3%
Share of variance in one series explained by the other.
Trend Agreement
65.6%
How often both series moved in the same direction period-to-period.
Overlap Quality
1,254
Deep shared window — 1,254 usable pairs.
Significance
p < 0.001
95% CI: [0.405, 0.493]
Scatter
XY Regression
Pipeline
Data quality details
Pipeline
Data quality details
Pipeline Summary
1,254 paired data points survived the daily window.
Raw input
1,254
1,254
Normalized
1,254
1,254
Prepared
1,254
1,254
Aligned
1,254
1,254
Invalid removed
0
A: 0 / B: 0
Duplicates removed
0
A: 0 / B: 0
Alignment drops
0
A: 0 / B: 0
Series A
BERKSHIRE HATHAWAY Class B
BRK.B
Market cap 1T
Stock · 1,254 raw → 1,254 prepared
Series B
General Motors Company
GM
Market cap 66.4B · 156,000 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
9
Estimated crossover points between normalized spreads.
Slope
0.0688
Linear regression slope.
Intercept
21.7171
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
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