VOL. XCIV, NO. 247

★ WIDE MOAT STOCKS COMPARISON ★

NO ADVICE

Saturday, January 10, 2026

Stock Comparison

Arthur J. Gallagher & Co. vs Marsh & McLennan Companies, Inc.

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

Arthur J. Gallagher & Co.

AJG · New York Stock Exchange

Market cap (USD)$67.9B
Gross margin (TTM)
Operating margin (TTM)
Net margin (TTM)
SectorFinancials
IndustryInsurance - Brokers
CountryUS
Data as of2026-01-09
Moat score
69/ 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 Arthur J. Gallagher & Co.'s moat claims, evidence, and risks.

View AJG analysis

Marsh & McLennan Companies, Inc.

MMC · New York Stock Exchange

Market cap (USD)$91.5B
Gross margin (TTM)42.3%
Operating margin (TTM)23.2%
Net margin (TTM)15.6%
SectorFinancials
IndustryInsurance - Brokers
CountryUS
Data as of2025-12-31
Moat score
65/ 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 Marsh & McLennan Companies, Inc.'s moat claims, evidence, and risks.

View MMC analysis

Comparison highlights

  • Moat score gap: Arthur J. Gallagher & Co. leads (69 / 100 vs 65 / 100 for Marsh & McLennan Companies, Inc.).
  • Segment focus: Arthur J. Gallagher & Co. has 2 segments (86% in Brokerage); Marsh & McLennan Companies, Inc. has 2 segments (62.8% in Risk and Insurance Services).
  • Moat breadth: Arthur J. Gallagher & Co. has 4 moat types across 2 domains; Marsh & McLennan Companies, Inc. has 5 across 3.

Primary market context

Arthur J. Gallagher & Co.

Brokerage

Market

Insurance and reinsurance brokerage and consulting

Geography

Global

Customer

Commercial, industrial, public sector, nonprofit and other organizations; underwriting enterprises for reinsurance placements

Role

Intermediary / broker / advisor

Revenue share

86%

Marsh & McLennan Companies, Inc.

Risk and Insurance Services

Market

Insurance brokerage, risk advisory, and reinsurance brokerage/services

Geography

Global

Customer

Enterprises, public entities, associations, and individuals (via broker/agent channels)

Role

Intermediary + advisor (insurance/reinsurance market intermediary)

Revenue share

62.8%

Side-by-side metrics

Arthur J. Gallagher & Co.
Marsh & McLennan Companies, Inc.
Ticker / Exchange
AJG - New York Stock Exchange
MMC - New York Stock Exchange
Market cap (USD)
$67.9B
$91.5B
Gross margin (TTM)
n/a
42.3%
Operating margin (TTM)
n/a
23.2%
Net margin (TTM)
n/a
15.6%
Sector
Financials
Financials
Industry
Insurance - Brokers
Insurance - Brokers
HQ country
US
US
Primary segment
Brokerage
Risk and Insurance Services
Market structure
Oligopoly
Oligopoly
Market share
n/a
n/a
HHI estimate
n/a
n/a
Pricing power
Moderate
Moderate
Moat score
69 / 100
65 / 100
Moat domains
Supply, Demand
Supply, Demand, Legal
Last update
2026-01-09
2025-12-31

Moat coverage

Shared moat types

Service Field NetworkBrand TrustData Workflow Lockin

Arthur J. Gallagher & Co. strengths

Operational Excellence

Marsh & McLennan Companies, Inc. strengths

Switching Costs GeneralCompliance Advantage

Segment mix

Arthur J. Gallagher & Co. segments

Full profile >

Brokerage

Oligopoly

86%

Risk Management

Competitive

14%

Marsh & McLennan Companies, Inc. segments

Full profile >

Risk and Insurance Services

Oligopoly

62.8%

Consulting

Competitive

37.2%

Want the full wide moat stocks list?

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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.