The Business MemberNarrow moat

Alongside the 68.3 million Gold Star households sit 12.7 million Business memberships including affiliates¹ — restaurants, contractors, offices, convenience stores — and they are a materially different customer.

The mechanics differ first. Business membership is limited to businesses, including individuals with a business licence or comparable document, and business members may add additional cardholders as affiliates at the same annual fee, which no Gold Star member may do². So a single business account can produce several fee-paying cards. Costco also runs dedicated business centres, carrying "items tailored for food services, convenience stores and offices" with walk-in shopping and deliveries, and counts them inside the warehouse total³.

The behaviour differs more. A restaurant buying supplies visits far more often than a household and buys larger quantities of a narrower list; frequency, which is the whole engine of membership renewal, comes free. But it also buys on landed cost with a spreadsheet, has no emotional attachment to Kirkland Signature, and will move to a wholesaler if the price moves — none of the treasure-hunt behaviour that makes the consumer basket larger than intended.

The strategic value is counter-cyclical in an unobvious way. Business buying is driven by the customer's own trading rather than by consumer confidence, so it does not slump in lockstep with household spending; and small businesses respond to cost pressure by hunting harder for wholesale prices, which is Costco's proposition exactly.

The limit is that Costco does not disclose business members' share of sales, only their share of the count — 15.7% of paid memberships. There is no way from the outside to tell whether the business relationship is growing in value or only in number. The count itself has been close to flat: 12.7 million in 2025 against 12.5 million in 2024 and 12.2 million in 2023, while Gold Star grew from 58.8 million to 68.3 million over the same period.

That divergence is the measure. Business memberships growing at 2% a year while consumer memberships grow at 8% says the fastest-growing part of Costco is the part most exposed to the household.