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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.

BRK.B logo

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

DGX logo

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

Apr 9, 2021 — Apr 7, 2026Daily1,254 data pointsStockStock

Time Series

Relative Performance

Green: BRK.BGray: DGX36 of 1,254 points (sampled)

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

247250300350400450500522.1120.3140160180200213.3BERKSHIRE HATHAWAY Class BQuest Diagnostics Inc.Data pointsFit (r = 0.729)

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

BRK.B logo

BERKSHIRE HATHAWAY Class B

BRK.B

Market cap 1T

Stock · 1,254 raw → 1,254 prepared

Series B

DGX logo

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

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