Blue Nile sold diamonds it never owned, buying each stone after the order

Diamond retail was an inventory business by definition: stores bought polished stones, locked them in cases, and marked them up steeply — the filing points to mark-ups imposed by layers of intermediaries — to cover the capital, security and write-downs of stock that might sit for years. The buyer paid for the retailer's working capital as much as for the stone.

Incorporated in 1999 in Seattle, Blue Nile moved the showcase online and left the vault where it was: exclusive supplier agreements let the company display suppliers' diamond inventories on its website — live, searchable stone by stone — without holding the diamonds, purchasing only those its customers ordered, plus selective stock of stones it judged attractive.

The website is a window onto suppliers' vaults: a customer comparing certified stones sees real, available inventory that costs Blue Nile nothing to list; on ordering, the stone is bought and set. Carrying costs and mark-down risk mostly vanish, so the price to the consumer undercuts physical retail while gross margin holds near 19 percent; education content — the four Cs, ring builders — substitutes for the salesperson the store would have paid for.

Listed suppliers' certified stones as virtual inventory, buying each only after the order, so carrying costs vanish and the discount undercuts physical retail.

Diamonds are standardized and certified, so buyers can compare specs online without touching the stone.

Inventory stays with suppliers, so Blue Nile's costs scale with orders rather than preceding them.

Exclusive supplier agreements keep competitors from listing the same virtual stock, making the catalog a moat.

If a product's price mainly covers the cost of holding inventory, list suppliers' stock and buy only against confirmed orders to turn carrying costs into a price advantage.

Net sales grew from $348M (FY2011) to $480M (FY2015) across 40+ countries at ~19% gross margin, selling stones it did not hold The virtual-inventory showcase spread through luxury and big-ticket e-commerce — watches, gems, cars — wherever a trusted supplier's live stock can be listed and paid for only on order.