How Costco Uses Cheap Gas to Build a Membership Moat

TL;DR

Costco sacrifices gas profit margins to attract and retain members, generating 66% of net income from membership fees rather than product markups.

Key Takeaways

1Costco offers gas at 20–56 cents cheaper per gallon than competitors, despite typical gas markups being only 15–20 cents profit
2Membership fees generated $1.35 billion of Costco's $2.03 billion net income in Q2 2026, representing 66% of total net income
3Historically, membership fees have accounted for approximately 70% of Costco's net income
4Low-margin gas functions as an economic moat that justifies membership costs and locks in customer loyalty
5Costco's model relies on membership revenue with minimal direct costs, allowing the company to operate without marking up products

Notable Quotes

“For Costco, gas is actually an incredible moat.”

“Membership fees, which have this marginal cost to them, maybe the plastic card, made up 66% of Costco's net income.”

Chapters

1. Costco's Gas Price Advantage

Costco offers gas prices 20–40 cents per gallon cheaper than competitors, with LA showing price differences up to 56 cents; typical gas markups are 35–40 cents with only 15–20 cents as profit.

2. The Membership Fee Engine

In Q2 2026, membership fees of $1.35 billion made up 66% of Costco's $2.03 billion net income, with historically this ratio staying around 70%.

3. Gas as a Strategic Moat

Despite low margins on gas, Costco uses cheap fuel as an economic moat to attract and retain members, enabling profit through membership fees rather than product markups.

Key People & Entities

Costco: Warehouse retailer using low-margin gas pricing as a membership acquisition and retention strategy

Glossary

Economic Moat: A competitive advantage that protects a company from rivals and allows it to sustain profitability; in Costco's case, cheap gas that incentivizes membership.
Markup: The difference between the cost to acquire a product and the price at which it is sold; for gas, typically 35–40 cents per gallon.
Marginal Cost: The cost to produce or deliver one additional unit; for Costco membership cards, nearly zero once the system is in place.

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