Record gas volumes and tariff refunds: Costco turns macro noise into a share-grab

Costco's Q3 shows pricing authority at work — gas records, Section 301 refunds, and AI search quietly compounding value

COST · Earnings Call · 2026-05-28

In a quarter defined by macro noise — oil, tariffs, and a jittery consumer — Costco delivered a steady, predictable result that masked a pair of genuinely new developments. Net sales rose 11.6% with comparable sales up 9.8%, and the real story sits in the gas lane and in the sudden monetization of its tariff history. The stock, up roughly 15x over fifteen years, sits about 13% below its May peak — the market wanted more, and management's answer is: we're investing the spread in the member.

The gas pivot: record volumes as a loyalty engine

The headline of the quarter isn't in the P&L line items; it's at the fuel pump. Ron Vachris opened with:

All 3 4-week fiscal periods of the quarter set successive all-time company volume sales records, with the final 5 weeks of the quarter becoming our top 5 volume weeks ever.
Ron Vachris, President and CEO · 2026-05-28

This is gas inflations used as a strategic weapon, not a headwind. Higher prices drew first-time users to Costco's gas stations, and members who shop the pumps "typically spend more with us in the warehouse" — a loyalty engine with a long tail. The crossover dynamic is a recurring theme, but the Middle East supply shock made it acute. The global keyword tape for the period is dominated by Middle East impacting, fuel recapture, and elevated oil, and discount-store peers Dollar Tree and Gap separately flagged fuel costs the same week. As Gary Millerchip noted last quarter, “when gas prices are higher, that will tend to cause members to maybe take the extra mile” — Gary Millerchip, CFO · 2026-03-05. This time, Costco widened its gas price gaps, taking a deliberate short-term margin hit to buy volumes and long-term loyalty — the mix shift showing up as traffic +2.4% but ticket +7.3%.

Tariff refunds: a genuinely new, company-unique lever

The freshest development isn't operational — it's fiscal. Costco has begun filing Section 301 refund claims with US Customs, a process it says will roll in over the next few months, and it intends to hand a portion back to members:

our plan is to return to our members in some form the portion of tariffs that were passed on to them. How much we return and when depends on a variety of factors, including how much refund money we receive, and when it arrives, as well as developments in the lawsuit filed against the company regarding the return process.
Ron Vachris, President and CEO · 2026-05-28

Tariff refund is the #1 theme across the entire market this period, and Dollar Tree and Kohl's both flagged it in the same reporting window — but Costco is the only name converting it into a member-return program. It's a natural extension of the "first to lower, last to raise" doctrine Ron articulated last year: “we are going to continue to try and mitigate as much of this impact on tariffs as we can for our members.” — Ron Vachris, President and Chief Executive Officer · 2025-05-29 The difference now: refunds give management a self-funding pool, and the balance sheet can absorb the swing with effective net cash of $15.1B.

Margins, AI, and the price-investment calculus

The margin headline: core-on-core down 9 basis points, with the team actively investing in eggs, beef, and gas value. Gary Millerchip framed it as a deliberate choice: “we saw it as an opportunity recognizing that members were dealing with higher gas prices to really invest in increasing value to the member.” — Gary Millerchip, CFO · 2026-05-28 Said differently, a top line up 12% is financing the moat. Gross margin ex-gas was +1bp, and with a shrinking LIFO charge ($44M vs $130M a year ago, a +14bp tailwind) they had room to be generous. The most underappreciated growth lever is AI. AI search traffic more than tripled with the highest conversion rate on the site, as large language models now surface all-in value — delivery, installation, road hazard — that regular search missed. "We feel very bullish on this AI search... telling the whole Costco story about the true value of what we offer," per Ron Vachris. Retail media also passed a milestone with a Google Commerce & Media and YouTube partnership. But management stays disciplined: “while the volume of traffic generated from AI search is still low, we saw triple digit growth in Q3, and this activity had the highest conversion rate of all traffic coming to our site.” — Gary Millerchip, CFO · 2026-05-28

The special dividend question

The cash is there, but the stock's run complicates the math. Management repeated that a special dividend is "the most effective way" to return excess cash, but cautioned that with the stock at 47x earnings, “to be at a similar yield, our cash would need to be at a higher level than it was at the last special dividend” — Gary Millerchip, CFO · 2026-05-28. Meanwhile membership is healthy (executive members +9.6%, China launch ahead of plan), and the gas halo should keep renewals and spend sticky. This wasn't a quarter that broke new ground on SG&A (slight deleverage from healthcare) or margins. It's a demonstration that Costco's moat — value authority — works even better when the macro gets messy. The price action says the market wanted more; management's answer is that the spread buys the next decade of share. Interesting, not inflection.