Costco is known for bulk groceries, long checkout lines, and some of the cheapest gas prices around. But a proposal to build ...

Costco has announced plans to expand its gas station offerings in California in a major way, but even fans of the warehouse chain aren't happy about it.

December sales surged: comps +7%, e-commerce +18.9%, total sales +8.5% to $29.9B—see key category winners and stock impact.