As of November 7, 2026, Numerator's latest retail tracking puts Costco ahead of Kroger in United States grocery spending for the first time, at 8.4 percent against 8.2 percent for the 12 months ending September 30. Walmart remains far ahead at 20.3 percent, Albertsons holds 4.5 percent and Publix 4.1 percent. The order behind the leader changed; the leader did not. For a brand reading this as a headline about two retailers, the more useful question is what a shift of two tenths of a point says about where shoppers now complete a grocery trip, and whether the format that wins the trip can keep the item on the shelf when the shopper arrives.
The ranking changed, the market did not expand
The three-period series is the part worth keeping. Costco's share moved 7.7, then 7.9, then 8.4 percent; Kroger's moved 8.7, then 8.4, then 8.2. That is a slow crossing, not a single week of unusual shopping, and it happened while retailers were openly cutting prices. Walmart said it used tariff refunds to lower prices on thousands of items, Costco's chief executive said the company used the 184 million dollars it received in initial refunds mainly to reduce prices, and Kroger and Albertsons announced their own price investments. When the top four are all cutting at once, share moves on format and trip design rather than on a single price gap.
A narrow lead, and what it does not prove
Two tenths of a point is a difference in spending share inside a defined market, not a claim that one company sells more units or runs more stores. It does not establish that Costco is cheaper for every household, and it does not mean Kroger lost sales dollars simply because its share declined; the measure covers food and beverage spending across channels, with alcohol and cannabis excluded. Reading it as a verdict on either business would be overreach. Reading it as evidence that shoppers now spread grocery spending across more formats is not.
| Retailer | Share, 12 months to Sept 2026 | Share a year earlier | What the format asks of a brand |
|---|---|---|---|
| Walmart | 20.3 percent | 20.1 percent | Volume in a narrow assortment, price held every week |
| Costco | 8.4 percent | 7.9 percent | Fewer items, larger packs, one decision per category |
| Kroger | 8.2 percent | 8.4 percent | Promotion depth and shelf presence across many stores |
| Albertsons | 4.5 percent | not disclosed here | Local assortment and store-level execution |
Trade area logic, not banner logic
Warehouse clubs sell a trip, not a basket
A club asks the shopper to drive further, buy larger packs and accept a narrower assortment. That model wins when a household consolidates a month of staples into one visit, which is why a club can gain share without adding many locations. For a brand, the implication is that trade area analysis has to start from the trip the format is designed to win, not from the banner name. A category that needs frequent, small purchases will not travel well into a club, no matter how good the listing looks.
Mass merchants trade price for frequency
Walmart's 20.3 percent is more than double Costco's and larger than Costco and Kroger combined. That lead comes from frequency: a shopper who visits weekly for essentials also buys the category a brand is trying to sell. The practical consequence is that a brand can be strong in one format and invisible in the other without any change in product quality, because the two formats reward different pack sizes, different price points and different degrees of assortment depth.
What to instrument over the next two quarters
Share data is a lagging indicator, and a cross-format ranking tells a brand nothing about whether its own item was on the shelf when the shopper looked. The operating question is whether availability and price position are holding in the formats that are gaining, which requires measuring by format rather than by total retail sales. Consumer demand has moved toward fewer, larger trips, and category growth now depends on being present in the format that wins that trip.
The third field is the one most often skipped. A club listing and a supermarket listing can show the same shelf price while the unit economics differ by half, and a brand that compares listed prices across formats will conclude it is priced competitively when it is not. Converting to price per unit also makes it easier to see whether a price investment is real or is funded by a smaller pack.
Reading share without over-reading it
The most defensible conclusion from the November reading is that grocery spending is spreading across formats and that conventional supermarkets are absorbing the cost of that spread. Costco passing Kroger by two tenths of a point is a signal about direction, not a verdict on either company's health, and the datasets behind it describe where spending went rather than why each shopper chose a store. Brands that treat the number as a reason to rebalance distribution and availability measurement will get more from it than brands that treat it as a headline.
FAQ
Does the Numerator figure mean Costco is now a bigger grocer than Kroger?
It means Costco captured a larger share of food and beverage spending in the 12 months to September 30, 2026 under Numerator's definition. It is not a comparison of total revenue, store counts or unit volumes, and the two tenths of a point gap should be read as a direction rather than a decisive gap.
Why does the three-period series matter more than one reading?
Because a single period can be distorted by a promotion calendar or a weather event. Costco moved from 7.7 to 7.9 to 8.4 percent and Kroger from 8.7 to 8.4 to 8.2 across comparable periods, which shows a crossing that developed over two years rather than a single week.
What should a brand measure differently after this?
Distribution and rate of sale by format, store-level availability in the formats gaining share, and price per unit rather than listed price. Comparing listed prices across a club and a supermarket hides differences in pack size that decide the real price position.
Is price the reason the share moved?
Price cuts were widespread, with Walmart, Costco, Kroger and Albertsons all investing during the year, so a single price gap does not explain the crossing. The data describes where spending went, not why each shopper chose a store.
