Correlation Analysis
BERKSHIRE HATHAWAY Class B vs The Cigna Group
BRK.B vs CI
+0.543
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
The Cigna Group
↗CI
Cigna primarily provides pharmacy benefit management and health insurance services. Its PBM and specialty pharmacy services, which were greatly expanded by its 2018 merger with Express Scripts, are mostly sold to health insurance plans and employers. Its largest PBM contract is with the Department of Defense, and it recently won a multiyear deal with top-tier insurer Centene. In health insurance and other benefits, Cigna primarily serves employers through self-funding arrangements, and the company operates mostly in the US with 16 million US and 2 million international medical members covered as of December 2025.
Market cap 72.7B · 67,700 employees
Time Series
Relative Performance
Who Moves First
CI leads BRK.B by 6 days
CI tends to move before BRK.B.
After testing 13 timing shifts, the strongest relationship was +0.544 (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
+0.361
17 periods · Return correlation when both series rose
Both Falling
-0.666
10 periods · Return correlation when both series fell
Diverging
-0.682
8 periods · Return correlation when series moved apart
R-Squared
29.5%
Share of variance in one series explained by the other.
Trend Agreement
64.6%
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: [0.503, 0.581]
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
The Cigna Group
CI
Market cap 72.7B · 67,700 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
19
Estimated crossover points between normalized spreads.
Slope
0.2572
Linear regression slope.
Intercept
188.0591
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
Saved 7 hours ago · ID: stock-brk-b-vs-stock-ci-daily