The gold bars for sale at Costco are marked about 2%–3% over the spot price of gold, undercutting the premium charged by traditional gold dealers, who mark up gold prices between 1% and 30%.

Costco has mastered the impulse buy. Shoppers pop in for eggs or rotisserie chicken only to wheel out baskets piled higher ...

Amid an unstable stock market, investors have been driven towards one of the most stable investments out there: gold.