Correlation Analysis
Costco Wholesale Corp vs West Pharmaceutical Services, Inc.
COST vs WST
-0.540
Moderate inverse
When one moves up, the other tends to move down.
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
West Pharmaceutical Services, Inc.
↗WST
West Pharmaceutical Services is based in Pennsylvania and is a key supplier to firms in the pharmaceutical, biotechnology, and generic drug industries. West sells elastomer-based packaging components (including stoppers, seals, and plungers), nonglass containment solutions, and auto-injectors for injectable drugs, which include large-molecule biologics, peptides such as GLP-1 receptor agonists, and small-molecule drugs. The company reports in two segments: proprietary products (about 80% of total revenue) and contract-manufactured products (about 20% of total revenue). It generates approximately 55% of its revenue from international markets and 45% from the United States.
Market cap 18.5B · 10,800 employees
Time Series
Relative Performance
Who Moves First
COST leads WST by 6 days
COST tends to move before WST.
After testing 13 timing shifts, the strongest relationship was -0.560 (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
-0.103
15 periods · Return correlation when both series rose
Both Falling
+0.251
7 periods · Return correlation when both series fell
Diverging
-0.602
13 periods · Return correlation when series moved apart
R-Squared
29.1%
Share of variance in one series explained by the other.
Trend Agreement
62.0%
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: [-0.578, -0.499]
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
West Pharmaceutical Services, Inc.
WST
Market cap 18.5B · 10,800 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
5
Estimated crossover points between normalized spreads.
Slope
-0.1645
Linear regression slope.
Intercept
433.8640
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
COST
Costco Wholesale Corp
Highest
+0.977
Republic Services Inc.
RSG · 1,254 data points
Lowest
-0.912
Fiserv, Inc. Common Stock
FISV · 644 data points
WST
West Pharmaceutical Services, Inc.
Highest
-0.168
Tesla, Inc. Common Stock
TSLA · 1,254 data points
Lowest
-0.580
Walmart Inc. Common Stock
WMT · 1,254 data points
Saved 7 hours ago · ID: stock-cost-vs-stock-wst-daily