Costco keeps gold premiums low because its business model doesn’t rely on markup for profit, membership fees cover overhead instead. It buys gold bars and coins in bulk directly from mints and refiners, cutting out extra distributor layers that typically raise prices.
Costco also offers very few gold products, often just one or two SKUs, so it can negotiate better wholesale rates through concentrated volume. There’s minimal marketing, packaging, or in-store display cost compared to specialty coin dealers.
Combined with thin margins across all Costco products, this lets gold sell close to spot price. It’s not actually “cheap,” just lower premium than typical retail dealers charge.