How Costco’s gas stations became a record-breaking competitive force

Inside Costco’s Record-Breaking Gasoline Sales Surge

A recent family road trip across the country drove home what Costco executives are now quantifying: the warehouse club’s gas stations have evolved from a roadside convenience into a record-smashing competitive asset. During the third quarter of 2026, gasoline comparable-store sales at Costco jumped more than 20%, with CEO Ron Vachris telling investors that all three four-week fiscal periods set successive all-time company volume records. The final five weeks of the quarter became the five highest-volume weeks in Costco’s history.

“Our gas team performed exceptionally well to manage this unprecedented demand, which requires multiple daily gas deliveries to many locations,” Vachris said. The momentum is not slowing: in June, Costco opened a standalone gas station in Mission Viejo, California — a format that moves fueling away from the warehouse and gives it prime real estate. For consumers, the lure is price. At a Costco pump in Merced, California, a gallon cost under $5.16, far below the local average, which regularly draws lines of cars snaking around the block.

What the Gas Volumes Reveal About Costco’s Competitive Edge

The Loss-Leader That Prints Volume

Costco’s fuel strategy has long been to sell gasoline at razor-thin margins — often the lowest price in any given market — to drive membership renewals and traffic to the warehouse. The latest numbers show this is working at an extraordinary scale. The 20% comp-sales jump in a single quarter indicates that even as overall vehicle miles traveled may fluctuate, the membership model and a reputation for price have turned Costco pumps into a default fuel stop for a growing number of households.

Where Competition Feels the Squeeze

The volume records do not happen in a vacuum. Every additional gallon sold by Costco is a gallon that did not go to a traditional gas station, a supermarket fuel center, or a convenience store chain. In markets like California, where pump prices are notoriously high, Costco’s ability to undercut competitors puts pressure on operators that rely on fuel margins to support store sales or station profitability. Rivals such as Kroger’s fuel centers or Sam’s Club face a competitor that is now actively expanding standalone sites rather than treating gas as a side lot.

Standalone Stations: A New Expansion Play

The Mission Viejo opening signals a willingness to scale fueling infrastructure apart from the main warehouse, potentially lowering land costs and allowing faster entry into dense urban or suburban areas where a full-store footprint is impossible. It also raises the question of how far Costco can push the model: if standalone pumps succeed, gas could become a franchise-like traffic generator, increasing the “halo effect” that turns a tank of petrol into a larger shopping trip.

What Retailers and Competitors Should Take Away

• For competitor retailers with fuel: Run a market-by-market price comparison against nearby Costco stations. If your pump price consistently exceeds Costco’s by more than 15–20 cents, a segment of price-sensitive shoppers is likely defecting, eroding both fuel gallons and potential in-store visits.
• For traditional gas station operators: Differentiate on speed, amenities, and loyalty programs. Costco pumps rarely offer the quick in-and-out experience of a c-store; emphasizing no-wait fueling, better coffee, or tailored rewards can give commuters a reason to skip the line.
• For investors and retail strategists: Expect meaningful capital allocation toward Costco’s fuel infrastructure. The record volumes and the standalone-station test suggest management sees gas as a durable growth lever, not a mature, defensive business.