Costco Posts Its Strongest Sales Growth in Nearly Four Years as Protein Products and Fuel Traffic Lift Results

ISSAQUAH, WA — Costco turned in its best sales growth in almost four years during the third quarter of fiscal 2026, with net sales rising 11.6% to just over $69 billion from $62 billion a year earlier. U.S. comparable-store sales, excluding fuel and foreign exchange, climbed 6.8%.

Executives said the quarter got a lift from shoppers looking for protein-focused products, along with steady demand in food and sundries and strong traffic at the company’s gas stations.

Protein demand becomes a bigger sales driver

During Thursday’s earnings call, chief financial officer Gary Millerchip said interest in GLP-1 medications has been showing up in Costco’s sales, especially in categories tied to protein. He said “anything protein” was selling particularly well.

The company pointed to a newly introduced private-label beef stick as one of its standout items, with Millerchip describing it as moving “tremendous volume” and giving members strong value. President and CEO Ron Vachris also said Costco’s Kirkland Signature ultra-filtered protein milk “has just taken off.”

Food, staples and gas kept members coming back

Grocery sales were another important piece of the quarter. Comparable sales in food and sundries rose in the mid-single digits, led by packaged foods and candy, while protein snacks and bars also posted significant growth. Lower egg prices weighed on sales somewhat, but that was partly balanced by stronger demand in other protein categories.

Vachris said Costco recorded record-breaking volumes in each month of the quarter. He tied that to consumer price sensitivity, which he said has been heightened by elevated fuel costs. The company’s gas stations also remained a major draw, bringing in many members who were buying fuel from Costco for the first time.

Costco keeps leaning on value as margins stay under pressure

Costco said food margins edged down in the quarter in part because it invested in keeping prices low on key items such as beef and eggs. Millerchip said the company wants to be first to lower prices when it sees an opportunity.

Higher fuel costs also pushed transportation expenses up during the period. Even so, executives said customers who use Costco’s fuel stations tend to spend more once they enter the warehouse, giving the retailer another reason to keep the gas business central to its value proposition.

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