Costco members have struck gold at the big box retailer, which sells 24-karat 1-ounce gold bars.

A report from Wells Fargo says 1 ounce gold bars are now generating up to $200 million a month in sales for Costco.

Costco members in the U.S. will soon have access to a weight loss program through Sesame, a health care marketplace.

ABC News’ Linsey Davis spoke with Costco superfans David and Susan Schwartz on what they learned about the wholesale retailer after traveling to over 250 Costco stores around the world.

"They're typically gone within a few hours," a Costco executive said.

Novaform ComfortGrande and DreamAway mattresses that were sold exclusively at Costco have been recalled due to the risk of possible mold exposure.