Correlation Analysis
Costco Wholesale Corp vs Western Digital Corp.
COST vs WDC
+0.480
Moderate 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
Western Digital Corp.
↗WDC
Western Digital is a leading vertically integrated supplier of hard disk drives. The HDD market is a practical duopoly, with Western Digital and Seagate being the two largest players. Western Digital designs and manufactures its HDDs, with much of the manufacturing and workforce located in Asia. The primary consumers of HDDs are data centers.
Market cap 103.1B · 40,000 employees
Time Series
Relative Performance
Who Moves First
in sync
COST and WDC tend to move at the same time.
After testing 13 timing shifts, the strongest relationship was +0.480 (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
+0.440
13 periods · Return correlation when both series rose
Both Falling
+0.953
6 periods · Return correlation when both series fell
Diverging
-0.731
16 periods · Return correlation when series moved apart
R-Squared
23.0%
Share of variance in one series explained by the other.
Trend Agreement
60.4%
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: [0.436, 0.522]
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
Western Digital Corp.
WDC
Market cap 103.1B · 40,000 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
3
Estimated crossover points between normalized spreads.
Slope
0.1178
Linear regression slope.
Intercept
-9.5377
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
Saved 9 hours ago · ID: stock-cost-vs-stock-wdc-daily