Charlie Munger said that the only real threat to Amazon in retail in his opinion was Costco. I think he has a point. Costco has a remarkable business model.
This part in the 2018 annual report summarizes the business pretty well
We operate membership warehouses based on the concept that offering our members low prices on a limited selection of nationally branded and private-label products in a wide range of categories will produce high sales volumes and rapid inventory turnover. When combined with the operating efficiencies achieved by volume purchasing, efficient distribution and reduced handling of merchandise in no-frills, self-service warehouse facilities, these volumes and turnover enable us to operate profitably at significantly lower gross margins (net sales less merchandise costs) than most other retailers. We generally sell inventory before we are required to pay for it, even while taking advantage of early payment discounts.
We buy most of our merchandise directly from manufacturers and route it to cross-docking consolidation points (depots) or directly to our warehouses. Our depots receive large shipments from manufacturers and quickly ship these goods to warehouses. This process creates freight volume and handling efficiencies, lowering costs associated with traditional multiple-step distribution channels
The model can be illustrated as below
Costco’s customer base enables the retailer to buy goods in bulk and at discount from suppliers. The lower prices make Costco appealing to customers. The cycle keeps going on. Costco has every reason to keep the margin low so that the cycle is robust and going strong. To solve the margin issue, Costco resorts to membership fees which are mostly purely profit.
The graph above shows that the membership fees make up the most of the net income. It’s not unreasonable to think that the SG&A expense for memberships is minimal.
The membership fees give Costco breathing room in a cut-throat business. There is only so much that a retailer can do on a margin side given a litany of fearsome competitors. Plus, there are so many foreseen and unforeseen factors that can put Costco’s margin at risk. If Costco removed the membership fees and raised the margin, they would become less competitive.
Being able to convince shoppers to pay an annual fee is a competitive advantage. So is the freedom to laser-focus on keeping the costs low. An additional advantage of a membership fee is that Costco can have more cash for their operations. Operating in a business in which a lot of goods are moved around every day and plenty of capital is required for upgrade, openings and renovation, Costco benefits greatly from the instant dose of cash the members bring in.