Correlation Analysis
BERKSHIRE HATHAWAY Class B vs Quest Diagnostics Inc.
BRK.B vs DGX
+0.729
Strong 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

Quest Diagnostics Inc.
↗DGX
Quest Diagnostics is a leading independent provider of diagnostic testing, information, and services in the US. The company generates over 97% of its revenue through clinical testing, anatomic pathology, esoteric testing, and substance abuse testing with specimens collected at its national network of roughly 2,400 patient service centers, as well as multiple doctors offices and hospitals. The firm also runs a much smaller diagnostic solutions segment that provides clinical trials testing, risk-assessment services, and information technology solutions.
Market cap 21.9B · 57,000 employees
Time Series
Relative Performance
Who Moves First
in sync
BRK.B and DGX tend to move at the same time.
After testing 13 timing shifts, the strongest relationship was +0.729 (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
-0.449
15 periods · Return correlation when both series rose
Both Falling
+0.569
7 periods · Return correlation when both series fell
Diverging
-0.619
13 periods · Return correlation when series moved apart
R-Squared
53.1%
Share of variance in one series explained by the other.
Trend Agreement
60.2%
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: [0.702, 0.754]
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

Quest Diagnostics Inc.
DGX
Market cap 21.9B · 57,000 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
5
Estimated crossover points between normalized spreads.
Slope
0.1731
Linear regression slope.
Intercept
84.0280
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
Saved 6 hours ago · ID: stock-brk-b-vs-stock-dgx-daily