The One Metric That Makes Costco Wholesale Stock Vulnerable

Sales are strong, and the warehouses are busy, but a slowdown in one crucial number could challenge the foundation of the company’s growth.

For years, holding Costco Wholesale (COST) stock has felt like a sure thing. The company’s blend of value, quality, and the treasure hunt experience has built a fiercely loyal membership base and a premium stock price to match. But with the stock already under pressure and well off its highs, it’s worth looking past the headline sales figures for signs of stress.

There is one number, buried in the quarterly metrics, that should give any Costco investor pause: shopping frequency. In the most recent quarter, worldwide traffic to its warehouses increased just 2.4%. On its own, that number sounds fine. But it represents a clear and concerning deceleration.

How Sharp Is The Slowdown?

Context is everything. That 2.4% growth in the third quarter follows a stronger 3.1% increase in the second quarter. Go back further, and the trend becomes more apparent; a year-ago quarter saw traffic growth as high as 5.2%. A steady decline like this suggests the magnetic pull of a Costco trip may be weakening, even if slightly. While members are still coming, they are coming less often, a subtle but meaningful shift in behavior.

This matters immensely because Costco is a volume business. Its entire model is built on getting members through the door. Slower traffic growth puts all the pressure on the other half of the sales equation: the average amount spent per visit. In the last quarter, the average ticket size jumped 7.3%, which helped deliver strong overall comparable sales growth of 6.6% when adjusted for gas and currency fluctuations. But relying on a bigger basket to drive growth is a less durable strategy than getting more footsteps in the door.

Why This Threatens A Premium Stock

The core risk here is to the stock’s valuation. Costco currently trades at a price-to-earnings multiple of 48.1, a level that suggests the market expects near-flawless execution and continued strong growth. That premium is built on the assumption that the company’s powerful growth algorithm remains intact.

Slowing traffic is a direct threat to that algorithm. The issue is compounded by a similar slowdown in new member acquisition. Total paid members grew 4.1% in the last quarter, a pace one analyst on the earnings call described as the lowest level in some time. Though management pushed back on that read, framing 4.1% as a more normal rate of growth once you strip out the lift from new market entries that had flattered prior periods.

If you have fewer new members joining, you need your existing ones to visit more frequently to keep the growth engine humming. Right now, both levers are decelerating. And, while management frames that as normalization rather than weakness, the bull case still needs at least one of them to re-accelerate.

If this trend in shopping frequency continues, it will become much harder for Costco to produce the kind of robust comparable sales growth that justifies its premium multiple. The stock price has already shown some sensitivity to growth concerns. A sustained traffic slowdown could give the market a reason to rethink what it’s willing to pay for the business.

It is a pattern we see across the market right now—as we noted recently, Cisco Stock Looks Strong, But One Number Says Be Careful, for very similar, underlying reasons.

For investors, the question is whether this is a temporary lull or the new normal. The single most important signal to watch in the coming quarters will be if that traffic number stabilizes or continues its slide.

Don’t Bet It All On One Number

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