How Jim Sinegal built Costco by treating customers like partners

The origin

Jim Sinegal grew up in Pittsburgh and worked his way through college as a bagger at FedMart, a discount retailer in San Diego. He stayed for twenty years, eventually becoming executive vice president under Sol Price, the man who invented the warehouse retail concept. When Price Club — Sol's next venture — opened in 1976, Sinegal was a senior executive there.

In 1983, Sinegal left to co-found Costco with attorney Jeffrey Brotman. The first warehouse opened in Seattle, a city Sinegal chose partly because of its demographics — well-educated, higher-income households who would appreciate quality goods at low prices — and partly because Seattle's distance from Price Club's California base gave Costco room to grow without immediate competition.

The operating model was inherited directly from Sol Price's framework: a membership fee, a limited SKU count, bulk packaging, and margins kept deliberately thin. What Sinegal added was a formalization of the margin cap that became Costco's most distinctive policy. No branded item would carry more than 14% gross margin. No private-label item would carry more than 15%. These were not targets — they were limits.

The challenge

Retailers measure success in gross margin. Department stores operate at 40-50%. Specialty retailers often higher. The logic is straightforward: margins cover the costs of operating the business and generate profit. A retailer that caps margins at 14% is, by this reasoning, leaving money on the table.

Sinegal's counterargument was that the margin cap was itself a marketing strategy — one that required no advertising budget. If customers knew that Costco would never charge more than 14% over cost on a branded item, they had a reason to trust the price they saw. They didn't need to comparison-shop. They didn't need a coupon. They didn't need a sale. The price was already correct.

The membership fee — initially $25, now $65 — served multiple functions. It screened for committed customers (someone who pays to enter a store has already decided they're going to buy). It generated a revenue stream that was almost pure profit and that cushioned the thin operating margins. And it created a psychological commitment: members felt they had to get their money's worth.

The breakthrough

The real test of the margin cap came in the early years when vendors pressured Costco to raise margins. Sinegal refused. A Coca-Cola executive once told him that Costco was charging too little for Coke products and damaging the brand. Sinegal's reply was to pull Coke from the shelves. Coke came back. The margin cap stayed.

This kind of pricing discipline was matched by a product curation discipline. Costco carries roughly 4,000 SKUs — about one-tenth of what a typical supermarket stocks. Every item on the floor has to earn its place by selling in volume. Items that don't move are cut. This keeps inventory costs down and gives Costco the purchasing leverage to demand better prices from suppliers.

The Kirkland Signature private-label brand, launched in 1992, extended the logic. Kirkland products are manufactured by the same suppliers who make the branded equivalents — often literally the same product, with different packaging. The Kirkland motor oil was made by Mobil. The Kirkland toilet paper was made by Charmin. The Kirkland coffee was sourced through Starbucks's supply chain. By making the provenance visible, Costco built the trust that made members willing to buy private label.

The impact

Costco generates over $220 billion in annual revenue with fewer than 600 warehouse locations worldwide. Its revenue per square foot is among the highest of any retailer. Its employee turnover rate is under 6% annually, compared to the industry average of over 60% — a cost advantage that compounds across every level of the operation.

Costco's stock has outperformed Walmart, Amazon, and the S&P 500 over the past twenty years. The compound annual return for a shareholder who held from 2003 to 2023 exceeded 15%. The company that capped its margins at 14% made its investors very rich.

The legacy

Sinegal stepped down as CEO in 2012 and remains on the board. He was known for answering his own phone, flying coach, and wearing the same blue employee uniform to the warehouse as everyone else. His salary as CEO was $350,000 a year — low by Fortune 500 standards, a deliberate signal about company culture.

The lesson Costco teaches is not about warehouses or bulk packaging. It is about what happens when you make a specific, enforceable promise to your customers and hold it even when it hurts.

The margin cap was itself a marketing strategy — one that required no advertising budget.

The SMB owner who reads this story and tries to implement a margin cap will face the same pressure Sinegal faced: vendors, advisors, and financial models will push for higher margins. The question to ask is the one Sinegal answered over four decades: do you want to maximize margin in the short term, or do you want to build the kind of trust that brings customers back without a marketing campaign?

Both are valid business strategies. Costco's choice just happens to be worth $300 billion.