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Correlate

Correlation Analysis

BERKSHIRE HATHAWAY Class B vs Equity Residential

BRK.B vs EQR

-0.342

Light 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

EQR logo

Equity Residential

EQR

Equity Residential owns a portfolio of 318 apartment communities with over 86,000 units and is developing three additional properties with 935 units. The company focuses on owning large, high-quality properties in the urban and suburban submarkets of Southern California, San Francisco, Washington, D.C., New York, Seattle, and Boston.

Market cap 22.7B · 2,400 employees

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

Time Series

Relative Performance

Green: BRK.BGray: EQR36 of 1,254 points (sampled)

Who Moves First

EQR leads BRK.B by 6 days

EQR tends to move before BRK.B.

After testing 13 timing shifts, the strongest relationship was -0.348 (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

+0.325

15 periods · Return correlation when both series rose

Both Falling

+0.460

10 periods · Return correlation when both series fell

Diverging

-0.476

10 periods · Return correlation when series moved apart

R-Squared

11.7%

Share of variance in one series explained by the other.

Trend Agreement

64.7%

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: [-0.390, -0.292]

Scatter

XY Regression

247250300350400450500522.151.46070809095.7BERKSHIRE HATHAWAY Class BEquity ResidentialData pointsFit (r = -0.342)

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

EQR logo

Equity Residential

EQR

Market cap 22.7B · 2,400 employees

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

-0.0376

Linear regression slope.

Intercept

83.9559

Linear regression intercept.

Related Extremes

Highest and Lowest Correlated

Saved 6 hours ago · ID: stock-brk-b-vs-stock-eqr-daily