Costco Through the Lens of a K-Shaped Economy 

Costco’s latest earnings don’t just tell us how one retailer is performing; they offer a snapshot of a K-shaped economy in action. On one side, higher-income households are still filling carts and renewing memberships without blinking. On the other hand, more stretched consumers are trading down, hunting for value, and leaning on bulk buying to make paychecks go further. Costco is managing to serve both, and its results show how uneven, yet surprisingly resilient, this economy really is. 

Costco Earnings Look Like the “Upper Leg” of the K 

Costco just delivered another strong quarter: 

• Revenue: about $67.3 billion, above Wall Street expectations 

• Earnings: $4.50 per share, beating estimates 

• Same-store sales (ex-gas): up 6.4%, ahead of forecasts 

Traffic is rising, basket sizes are bigger, and membership keeps climbing toward 146 million cardholders globally. Holiday demand, food court/bakery momentum, and value-focused private-label (Kirkland) all helped drive the beat. 

Increasingly, analysts point out that Costco’s most affluent, most loyal members are doing a lot of the heavy lifting. Executive members who can still spend on bulk groceries, discretionary items, and even big-ticket purchases. That’s classic “top of the K” behavior. 

What is a K-Shaped Economy? 

A K-shaped economy is one where different groups diverge sharply: 

• Higher-income households, strong sectors, and “winner” companies move up – incomes and spending stay resilient or even grow. 

• Lower-income households and vulnerable sectors move down. Wages lag, savings thin out, and spending shifts to essentials or cheaper substitutes. 

Recent research and card-data analysis show this split clearly: prime, higher-income consumers maintain solid spending, while non-prime and lower-income groups pull back, rely more on credit, or cut discretionary categories. 

Costco in the middle of the K 

Costco sits in a fascinating spot in this story: 

The upper-leg consumer is thriving at Costco 

• Higher-income households are still willing to pay the membership fee. 

• They treat Costco as a one-stop shop for everything from groceries to electronics and travel. 

• For them, bulk buying is less about survival and more about value optimization by getting quality and convenience with a perceived bargain. 

That helps explain why comps and memberships keep rising even in a choppy macro backdrop. 

The Lower-Leg Consumer is Trading toward Costco 

At the same time, a K-shaped economy often pushes more budget-constrained households to trade down: 

• From premium grocers to warehouse clubs 

• From branded goods to private label 

• From multiple small trips to fewer bulk runs to stretch each dollar 

Costco benefits from this “value migration,” even as some of those shoppers are clearly under more stress. The same macro environment that strains the bottom leg of the K can actually support traffic in value-heavy formats. 

What Costco’s quarter is really telling us 

Costco’s strong earnings don’t mean everyone is doing fine. They mean: 

• Resilient, higher-income consumers are still spending, especially where they perceive clear value. 

• Stressed households are adjusting behavior, often in ways that can still support volumes at discount/value retailers. 

• The average looks healthy, but underneath, the distribution is skewed, very much in line with a K-shaped pattern. 

For markets, this dynamic matters for: 

• Retail stock selection: formats serving the top leg (or both legs via value) can still post solid growth. 

• Credit and default risk: the lower leg shows up more in credit delinquencies and subprime stress than in Costco’s earnings line. 

• Policy and inflation: strong upper-leg demand can keep certain categories and services inflated, even as other households pull back. 

If you want to go deeper into macroeconomics, you can explore more inside IBKR InvestMentor