Correlation Analysis
BERKSHIRE HATHAWAY Class B vs eBay Inc
BRK.B vs EBAY
+0.580
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
eBay Inc
↗EBAY
EBay operates one of the largest e-commerce marketplaces in the world, with $79.6 billion in 2025 gross merchandise volume, rendering the firm a top 10 global e-commerce company. It generates sales from listing fees, advertising, revenue-sharing arrangements with service providers, and managed payments, with its platform connecting about 135 million buyers and roughly 20 million sellers across almost 190 global markets at the end of 2025. EBay generates just north of 50% of its GMV in international markets, with a large presence in the UK, Germany, and Australia.
Market cap 43.8B · 12,300 employees
Time Series
Relative Performance
Who Moves First
BRK.B leads EBAY by 6 days
BRK.B tends to move before EBAY.
After testing 13 timing shifts, the strongest relationship was +0.588 (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
-0.119
13 periods · Return correlation when both series rose
Both Falling
+0.207
6 periods · Return correlation when both series fell
Diverging
-0.670
16 periods · Return correlation when series moved apart
R-Squared
33.7%
Share of variance in one series explained by the other.
Trend Agreement
63.9%
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: [0.542, 0.616]
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
eBay Inc
EBAY
Market cap 43.8B · 12,300 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
13
Estimated crossover points between normalized spreads.
Slope
0.1118
Linear regression slope.
Intercept
17.5145
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
Saved 7 hours ago · ID: stock-brk-b-vs-stock-ebay-daily