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Correlation Analysis

Costco Wholesale Corp vs Paychex Inc

COST vs PAYX

+0.527

Moderate positive

When one moves up, the other tends to follow.

COST logo

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

PAYX logo

Paychex Inc

PAYX

Paychex is a technology company providing human capital management solutions, enabling clients to better implement payroll, talent, time, tax, and benefits administration. It has a diverse set of product offerings addressing client needs. Aside from its traditional cloud-based payroll and HCM software offering, which accounts for close to half of total revenue, the company provides outsourcing options. Paychex's administrative service organization and professional employer organization accounts generate over 40% of sales. The balance of revenue is generated through retirement services, insurance solutions, and other products. In fiscal 2025, the company had 800,000 clients and almost 2.5 million worksite employees across its ASO and PEO.

Market cap 32.9B · 19,000 employees

Apr 9, 2021 — Apr 7, 2026Daily1,254 data pointsStockStockConsumer

Time Series

Relative Performance

Green: COSTGray: PAYX36 of 1,254 points (sampled)

Who Moves First

PAYX leads COST by 6 days

PAYX tends to move before COST.

After testing 13 timing shifts, the strongest relationship was +0.540 (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

+0.569

13 periods · Return correlation when both series rose

Both Falling

+0.119

10 periods · Return correlation when both series fell

Diverging

-0.665

12 periods · Return correlation when series moved apart

R-Squared

27.7%

Share of variance in one series explained by the other.

Trend Agreement

67.4%

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: [0.485, 0.565]

Scatter

XY Regression

3064006008001,0001,13486.4100120140160162.2Costco Wholesale CorpPaychex IncData pointsFit (r = 0.527)

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

COST logo

Costco Wholesale Corp

COST

Market cap 451.9B

Stock · 1,254 raw → 1,254 prepared

Series B

PAYX logo

Paychex Inc

PAYX

Market cap 32.9B · 19,000 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

0.0350

Linear regression slope.

Intercept

98.7877

Linear regression intercept.

Related Extremes

Highest and Lowest Correlated

Saved 4 hours ago · ID: stock-cost-vs-stock-payx-daily