VOL. XCIV, NO. 247

★ WIDE MOAT STOCKS COMPARISON ★

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Thursday, January 8, 2026

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Stock Comparison

Merck & Co., Inc. vs Paychex, Inc.

Compare moat strength, market structure, and segment coverage to understand how each company defends its edge.

Merck & Co., Inc.

MRK · New York Stock Exchange

Market cap (USD)$270B
Gross margin (TTM)78.3%
Operating margin (TTM)36.4%
Net margin (TTM)29.6%
SectorHealthcare
IndustryDrug Manufacturers - General
CountryUS
Data as of2025-12-22
Moat score
71/ 100

Weighted average of segment moat scores, combining moat strength, durability, confidence, market structure, pricing power, and market share.

Full stock profile

Dive deeper into Merck & Co., Inc.'s moat claims, evidence, and risks.

View MRK analysis

Paychex, Inc.

PAYX · NASDAQ Global Select Market

Market cap (USD)$39.4B
Gross margin (TTM)73.4%
Operating margin (TTM)37.1%
Net margin (TTM)26.5%
SectorIndustrials
IndustryStaffing & Employment Services
CountryUS
Data as of2026-01-04
Moat score
66/ 100

Weighted average of segment moat scores, combining moat strength, durability, confidence, market structure, pricing power, and market share.

Full stock profile

Dive deeper into Paychex, Inc.'s moat claims, evidence, and risks.

View PAYX analysis

Comparison highlights

  • Moat score gap: Merck & Co., Inc. leads (71 / 100 vs 66 / 100 for Paychex, Inc.).
  • Segment focus: Merck & Co., Inc. has 2 segments (89.5% in Pharmaceutical); Paychex, Inc. has 3 segments (73% in Management Solutions).
  • Primary market structure: Competitive vs Oligopoly. Pricing power: Moderate vs Moderate.
  • Moat breadth: Merck & Co., Inc. has 5 moat types across 3 domains; Paychex, Inc. has 7 across 4.

Primary market context

Merck & Co., Inc.

Pharmaceutical

Market

Branded prescription pharmaceuticals & human vaccines

Geography

Global

Customer

Wholesalers/retailers, managed care and government payers, hospitals/clinics

Role

R&D-intensive innovator, manufacturer, and marketer

Revenue share

89.5%

Paychex, Inc.

Management Solutions

Market

Payroll processing and integrated HCM solutions for SMB and mid-market employers

Geography

United States (primarily)

Customer

Employers (SMB and mid-market)

Role

HCM SaaS + outsourced payroll/HR service provider

Revenue share

73%

Side-by-side metrics

Merck & Co., Inc.
Paychex, Inc.
Ticker / Exchange
MRK - New York Stock Exchange
PAYX - NASDAQ Global Select Market
Market cap (USD)
$270B
$39.4B
Gross margin (TTM)
78.3%
73.4%
Operating margin (TTM)
36.4%
37.1%
Net margin (TTM)
29.6%
26.5%
Sector
Healthcare
Industrials
Industry
Drug Manufacturers - General
Staffing & Employment Services
HQ country
US
US
Primary segment
Pharmaceutical
Management Solutions
Market structure
Competitive
Oligopoly
Market share
n/a
n/a
HHI estimate
n/a
n/a
Pricing power
Moderate
Moderate
Moat score
71 / 100
66 / 100
Moat domains
Legal, Supply, Demand
Demand, Supply, Legal, Financial
Last update
2025-12-22
2026-01-04

Moat coverage

Shared moat types

Data Workflow Lockin

Merck & Co., Inc. strengths

IP Choke PointRegulated Standards PipeCapex Knowhow ScaleScope Economies

Paychex, Inc. strengths

Suite BundlingService Field NetworkCompliance AdvantageUnderwriting Risk PoolingSwitching Costs GeneralFloat Prepayment

Segment mix

Merck & Co., Inc. segments

Full profile >

Pharmaceutical

Competitive

89.5%

Animal Health

Oligopoly

9.2%

Paychex, Inc. segments

Full profile >

Management Solutions

Oligopoly

73%

PEO and Insurance Solutions

Competitive

24.1%

Client funds float (interest on funds held for clients)

Oligopoly

2.9%

Want the full wide moat stocks list?

Browse the full ranking of wide moat stocks, updated with moat scores and segment context.

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Looking for expansion-stage stocks?

Proven models entering the expansion stage with unit economics that work.

View expansion-stage stocks

Curation & Accuracy

This directory blends AI‑assisted discovery with human curation. Entries are reviewed, edited, and organized with the goal of expanding coverage and sharpening quality over time. Your feedback helps steer improvements (because no single human can capture everything all at once).

Details change. Pricing, features, and availability may be incomplete or out of date. Treat listings as a starting point and verify on the provider’s site before making decisions. If you spot an error or a gap, send a quick note and I’ll adjust.