Correlation Analysis
Costco Wholesale Corp vs Markel Group Inc.
COST vs MKL
+0.908
Very strong positive
When one moves up, the other tends to follow.
Costco Wholesale Corp
↗COST
Founded in 1983, Costco Wholesale now operates a global chain of membership-based warehouse clubs, delivering high-quality goods and services at consistently low prices. As of its most recent fiscal year, Costco operated approximately 910 warehouses, serving more than 80 million members across its three geographic segments: Costco US (approximately 73% of total revenue), Costco Canada (13%), and Costco International (14%).Costco's core value proposition—quality products at unbeatable prices—has yielded consistently strong member renewal rates (93% in the US and Canada and nearly 90% internationally). About 55% of Costco's fiscal 2025 revenue came from its grocery offerings, and another 25% from general merchandise.
Market cap 451.9B
Markel Group Inc.
↗MKL
Markel's primary business is property and casualty insurance. The company focuses primarily on specialty lines, ranging from areas such as executive liability to commercial equine insurance. The acquisition of Alterra in 2013 added substantial reinsurance operations, which now account for a little over 10% of premiums. The company uses capital generated by its insurance operations to buy noninsurance operations in diverse areas, such as bakery equipment manufacturing and residential homebuilding.
Market cap 23.9B · 22,900 employees
Time Series
Relative Performance
Who Moves First
in sync
COST and MKL tend to move at the same time.
After testing 13 timing shifts, the strongest relationship was +0.908 (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
+0.719
14 periods · Return correlation when both series rose
Both Falling
N/A
4 periods · Return correlation when both series fell
Diverging
-0.697
17 periods · Return correlation when series moved apart
R-Squared
82.4%
Share of variance in one series explained by the other.
Trend Agreement
57.2%
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: [0.898, 0.917]
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
Costco Wholesale Corp
COST
Market cap 451.9B
Stock · 1,254 raw → 1,254 prepared
Series B
Markel Group Inc.
MKL
Market cap 23.9B · 22,900 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
69
Estimated crossover points between normalized spreads.
Slope
1.2101
Linear regression slope.
Intercept
693.1484
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
Saved 6 hours ago · ID: stock-cost-vs-stock-mkl-daily