⚠ Frequency Has Already Started to SlowHigh threat

Costco breaks its comparable sales into two components, and the split is the most informative number the company publishes about the health of the membership.

Fiscal 2025: comparable sales +6%, of which shopping frequency contributed approximately 5 points and average ticket approximately 1¹. Third quarter of fiscal 2026: comparable sales +10%, of which average ticket contributed approximately 7 points and frequency approximately 2². The mix inverted inside eighteen months.

The composition of that ticket increase matters. Higher gasoline prices added $1,367 million to net sales in the quarter, 221 basis points, on a 20% rise in the average price per gallon; foreign currency added a further 104 basis points. Strip both out and comparable sales were 7% rather than 10%, and ancillary businesses — gasoline and pharmacy — grew 29% while core merchandise grew 7%. The trolley did not get much fuller. The tank got more expensive.

This is not evidence of a broken business. It is evidence that the recent acceleration is lower quality than the headline suggests, and that the component which actually predicts renewal has decelerated from 5 to 2 while the renewal rate itself slipped a tenth of a point in both the domestic and worldwide measures³.

The falsifier is specific: frequency below 2 points for a full year while the fee is unchanged, with the renewal rate continuing to drift. That combination would say members were coming less often and finding the annual question harder to answer. Everything else on this page — the ancillary businesses, the food court, the fuel — exists to prevent exactly that, and their effectiveness is measured in this one series.