Costco: Membership Margins and Deliberate Discipline

Costco sells merchandise at margins so thin it barely profits on what it puts on the shelf. The Kirkland olive oil, the six-pound tub of cashews, the surprise designer handbags, all priced low enough to alarm a normal retailer. Yet the company is enormously profitable. The trick is that for decades, operating income has run roughly equal to membership fee revenue, and renewal rates have held above 90 percent. The product on the shelf is almost beside the point. Something else is doing the work.

For founders and operators, this is a case about profit architecture: deciding exactly where in your business you make money and where you deliberately make almost none. It sharpens the discipline of knowing your true profit center cold, so you can be strategically generous everywhere else, instead of guessing which parts of the business are actually carrying you.