Dive Brief:

• While receipts at many gas station-affiliated retailers fall when gas prices do, Costco Wholesale Corp. is escaping that fate by protecting its margins with higher prices that still appeal to its customers, according to analysis by the Wall Street Journal.

• Costco famously makes much, if not most, of its bank through its membership fees, which allows it to keep prices low. It’s also one of the largest fuel sellers in the U.S., with buying and selling power that allows it to buy lower and raise prices more slowly.

• Even when Costco’s prices are slow to fall, it still offers some of the lowest prices of any gas station retailer, usually 20 cents lower than its rivals, according to GasBuddy.com, the Journal reports.

Dive Insight:

This analysis from the Wall Street Journal has a back-of-the-napkin feel, as it explains how Costco’s success at the pump could help mitigate any fallout from its transition from an American Express store card to Citigroup co-branded cards.

The truth is that there are likely a lot of reasons for Costco members to fill up at the warehouse that are beneficial to the retailer and to its shoppers. Low prices are key, of course, but the retailer gets huge props from experts and members for its customer service and merchandise assortment.

The warehouse-style retailer has several benefits, including the browse-and-buy advantage of its brick-and-mortar locations. The retailer offers many products that consumers need or prefer to buy in-person, like gas or food, thus driving foot traffic to its stores.

Membership programs continue to be popular with consumers, with Amazon Prime and membership-based delivery services expanding. Costco currently counts 44.6 million households as members, bringing in $785 million in sales in Q4.

Costco has also long paid its workers well above minimum wage and provided them with relatively good benefits. That means that it is already at a competitive advantage, better able to attract workers at a time when unemployment is down and workers can be pickier. And it doesn’t have to invest heavily to play catch up, either, as Wal-Mart does, because it has already long had more employee-friendly policies in place.

Wal-Mart’s plan to increase wages and improve training, by contrast, will cost the retailer at least $1 billion, by its own estimates.