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Correlation Analysis

BERKSHIRE HATHAWAY Class B vs Pfizer Inc.

BRK.B vs PFE

-0.848

Strong inverse

When one moves up, the other tends to move down.

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

PFE logo

Pfizer Inc.

PFE

Pfizer is one of the world's largest pharmaceutical firms, with annual sales of roughly $60 billion. While it historically sold many types of healthcare products and chemicals, now prescription drugs and vaccines account for the majority of sales. Top sellers include pneumococcal vaccine Prevnar 13 and cardiology drugs Vyndaqel and Eliquis. Pfizer sells these products globally, with international sales representing 40% of total sales. Within international sales, emerging markets are a major contributor.

Market cap 158.3B

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

Time Series

Relative Performance

Green: BRK.BGray: PFE36 of 1,254 points (sampled)

Who Moves First

PFE leads BRK.B by 6 days

PFE tends to move before BRK.B.

After testing 13 timing shifts, the strongest relationship was -0.851 (they moved in opposite directions).

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

-0.307

9 periods · Return correlation when both series rose

Both Falling

+0.110

8 periods · Return correlation when both series fell

Diverging

-0.380

18 periods · Return correlation when series moved apart

R-Squared

71.8%

Share of variance in one series explained by the other.

Trend Agreement

60.3%

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: [-0.863, -0.831]

Scatter

XY Regression

247250300350400450500522.1203040506062.5BERKSHIRE HATHAWAY Class BPfizer Inc.Data pointsFit (r = -0.848)

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

PFE logo

Pfizer Inc.

PFE

Market cap 158.3B

Stock · 1,254 raw → 1,254 prepared

Sign agreement

100.0%

How often both values share the same sign.

Zero crossings

1

Estimated crossover points between normalized spreads.

Slope

-0.1033

Linear regression slope.

Intercept

75.0674

Linear regression intercept.

Related Extremes

Highest and Lowest Correlated

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