Costco stock valuation: Can COST sustain its premium?

Costco has spent years proving that a retailer can sell products at very low margins and still build one of the market's most valuable business models. Its warehouses keep attracting members, renewal rates remain close to 90% globally and fiscal 2026 net sales crossed $297 billion. Yet the investment question is no longer simply whether Costco is a great company. At a share price of $893.93 and nearly 45 times trailing earnings as of September 18, 2026, the more important question is whether the company can grow fast enough to justify what investors are already paying for it.

Let's break down Costco's latest growth, the economics of its membership model and the assumptions embedded in COST's premium valuation. We will also examine what could sustain the multiple, what could compress it and how Indian investors should interpret the stock before Costco's fiscal fourth-quarter results on September 24.

Why Costco stock's premium valuation is back in focus?

The timing of this debate matters. Costco has already disclosed its sales for the 52-week fiscal year ended August 30, 2026 but it has not yet reported the full profit statement for the fourth quarter and fiscal year. Those results are scheduled for September 24, which means investors know that sales remained strong but are still waiting to see how much of that growth reached operating profit and earnings per share.

The latest sales update was reassuring. Fiscal 2026 net sales rose 10.2% to $297.3 billion while company-wide comparable sales increased 8.4%. After removing the effects of fuel-price movements and foreign exchange, comparable sales grew 6.6%. Digitally enabled comparable sales rose 20.7% and Costco finished August with 939 warehouses worldwide.

These figures explain why the market still assigns Costco a premium. They do not by themselves prove that the premium is justified. A company can report excellent sales growth while its stock produces modest returns if investors previously paid too much for those earnings.

Costco's latest earnings show why investors pay more

The most recent complete earnings report is for the 12 weeks ended May 10, 2026. Third-quarter net sales increased 11.6% to $69.15 billion while total revenue including membership fees reached $70.53 billion. Net income rose 15.2% to $2.19 billion and diluted earnings per share increased from $4.28 to $4.93.

The quality of that quarter was not limited to revenue growth. Adjusted comparable sales rose 6.6% and shopping frequency increased 2.4% worldwide. Costco also generated $2.82 billion of operating income, giving it an operating margin of about 4.0%. That margin looks thin beside software or consumer-brand companies but it is consistent with Costco's strategy of keeping product mark-ups low to reinforce customer value.

Costco's first 36 weeks also showed modest operating leverage. Operating income rose 12.0% to $7.88 billion while total revenue increased 9.7% to $207.43 billion. The operating margin improved from approximately 3.72% to 3.80%. An eight-basis-point change may appear small but on more than $200 billion of revenue it has a meaningful effect on profit.

The membership model is Costco's real valuation engine

Costco is often described as a retailer but its economics resemble a subscription business attached to a high-volume warehouse network. The warehouses provide the value that attracts members while annual fees produce recurring revenue that is less volatile than merchandise margins.

At the end of the third quarter Costco had 82.9 million paid members and 149 million cardholders. Paid memberships grew 4.1% year on year while paid Executive memberships grew 9.6% to 41.2 million. This means Executive members accounted for almost half of paid memberships. Management says these members generally visit more frequently and spend more which makes the mix shift particularly valuable.

Renewal rates remained exceptional at 92.2% in the US and Canada and 89.7% worldwide. Membership fee income increased 10.7% to $1.37 billion during the quarter. The September 2024 fee increase produced a little more than one-quarter of that growth while fee income still grew about 7% after excluding the fee increase and foreign exchange.

There is one important analytical caution. Third-quarter membership fee revenue was equivalent to almost 49% of operating income but that does not mean every dollar of fees was pure profit. Costco incurs costs to acquire, serve and retain members. The comparison is still useful because it shows how central recurring fees are to the economics of the company without overstating their profitability.

Why Costco deserves a premium to other retailers?

Costco's premium is supported by four reinforcing advantages. First, high renewal rates make a meaningful portion of revenue more predictable. Second, the limited product assortment and large purchasing volumes strengthen its bargaining power with suppliers. Third, low product margins deepen member trust because customers have a reason to believe that Costco is protecting value. Fourth, the Kirkland Signature private label allows the company to offer attractive prices while controlling product quality and economics.

This creates a self-reinforcing system. Better prices attract and retain members. More members increase purchasing volume. Greater scale improves Costco's buying power and those savings can be returned to members through lower prices. Competitors can copy individual features but recreating the entire system is harder because it requires scale, trust and years of disciplined execution.

The balance sheet adds another layer of quality. At May 10, 2026 Costco held $18.95 billion in cash and cash equivalents plus $1.05 billion in short-term investments against $5.67 billion of long-term debt. Net cash gives the company room to build warehouses, invest in digital capabilities, raise ordinary dividends and consider occasional special dividends without weakening the core business.

How expensive is COST stock in September 2026?

At $893.93 per share Costco had a market value of approximately $397.3 billion and traded at about 45.0 times trailing earnings. Using the market's fiscal 2026 earnings estimate of roughly $20.58 per share produces a multiple of about 43.4 times expected earnings. In simple terms, investors are paying more than $43 for each dollar of anticipated fiscal 2026 profit.

That is a demanding valuation even after the stock declined roughly 18% from its May 2026 all-time closing high of $1,094.32. Walmart traded at about 38.4 times trailing earnings on the same date while BJ's Wholesale Club traded at about 20.4 times. These are not perfect like-for-like comparisons because their formats, revenue mixes, geographic exposure and growth rates differ. They do show that Costco's quality is not merely recognized by the market. It is already priced at a substantial premium.

A high P/E does not automatically mean a stock is overvalued. It means the business must deliver either faster earnings growth, more durable growth or lower risk than a lower-rated peer. Costco offers all three to some degree but the starting multiple leaves a narrow margin for disappointment.

What growth does Costco's current share price require?

The cleanest way to assess the premium is to work backwards from the current price. The following model starts with estimated fiscal 2026 EPS of $20.58 and projects earnings for three years. It then applies a possible P/E multiple at the end of that period and discounts the resulting share price back at 8% a year. The exercise is not a price target. It shows how sensitive today's valuation is to growth and the multiple that investors may be willing to pay later.

At the current price the lower-growth case produces a large valuation gap because both earnings growth and the future multiple moderate. Even the base case assumes double-digit EPS growth and a premium 38 times multiple yet its discounted value is slightly below the current market price. The high-growth case can support a materially higher value but it requires Costco to compound earnings at 14% and retain today's exceptionally high multiple three years from now.

Another way to view the same problem is to ask what must happen for an investor to earn an 8% annual return before dividends. If Costco trades at 40 times earnings after three years it would need EPS of roughly $28.15 at that point. That requires earnings to compound at about 11% a year from the fiscal 2026 estimate. If the future multiple falls to 35 times the required EPS rises to about $32.17 which would demand growth of roughly 16% a year. The lower the future valuation multiple, the more operating performance must compensate.

What could help Costco sustain its premium valuation?

The first support is continued comparable-sales growth. Costco delivered adjusted comparable-sales growth of 6.6% in fiscal 2026 and the same rate in its latest reported quarter. If existing warehouses keep producing mid-single-digit or better growth while new warehouses add members and sales, total revenue can continue rising without requiring aggressive pricing.

The second support is membership quality. Executive membership growth of 9.6% outpaced total paid-member growth of 4.1%. If that pattern continues, Costco can generate more fee income and spending from each member even if total membership growth settles into management's more normal 4% to 5% range.

The third support is digital growth. Digitally enabled comparable sales rose 20.7% in fiscal 2026 while site and app traffic increased 37% in the third quarter. Digital convenience can deepen engagement but investors should watch whether delivery and fulfilment costs allow that growth to improve profit rather than merely revenue.

The fourth support is international expansion. Costco added eight warehouses between the end of its third quarter and August and management has discussed a longer-term goal of more than 30 net new openings annually. New markets can create bursts of membership growth although openings require capital and early renewal behavior can differ from mature US and Canadian locations.

What could cause Costco's valuation premium to shrink?

The clearest risk is slower membership growth. Management described growth of 4% to 5% as a more normal rate when Costco is not entering a major new market. That is still healthy but it makes high-single-digit or double-digit fee growth more dependent on Executive upgrades, fee increases and retention.

Margin pressure is another risk because Costco deliberately returns savings to members. Third-quarter reported gross margin fell 21 basis points to 11.04% although it improved by one basis point after adjusting for fuel inflation. Core-on-core margin declined nine basis points as the company lowered prices on selected fresh foods and everyday items. This discipline strengthens the franchise over time but it can limit near-term profit expansion.

Multiple compression may matter more than a small earnings miss. If Costco's earnings grow 10% but the market decides that 35 times earnings is a more appropriate valuation than more than 40 times, the declining multiple can offset much of the benefit from higher profit. This is the central risk in premium-quality stocks: the business can perform well while shareholder returns remain ordinary.

Competition also deserves attention. Walmart's Sam's Club and BJ's continue investing in membership, private-label products and digital convenience. Costco does not need competitors to overtake it for the valuation to change. A modest reduction in perceived superiority could be enough for the market to narrow the premium.

What should investors watch in Costco's September earnings?

The September 24 report should be judged on more than whether EPS beats or misses the consensus estimate of about $6.55. Investors should compare membership fee growth with paid-member growth, examine whether Executive members continue gaining share and track renewal rates in the US and Canada as well as worldwide.

Margins will be equally important. Costco has already reported $93.9 billion in fourth-quarter net sales so the larger unknown is how fuel prices, wage costs, freight, price investments and sales mix affected gross and operating margins. The cash balance and any discussion of a special dividend may influence sentiment but a special dividend does not make the operating business more valuable. It simply transfers excess cash from the company to shareholders.

What Costco's valuation means for Indian investors?

Costco has no warehouse presence in India so an Indian investor buying Costco stock through the US market is primarily taking exposure to US and international consumer spending rather than India's retail growth. The company still offers geographic diversification through Canada, Mexico, Japan, the UK and other markets but the US remains its largest operating base.

Indian investors must also separate the company's dollar return from their return in rupees. A stronger dollar against the rupee can lift the rupee value of a US investment while a stronger rupee can reduce it. Currency can influence the final outcome but it should not be used to justify paying an excessive valuation for the underlying business.

Can COST sustain its premium valuation?

Costco can sustain a premium valuation because its membership model, renewal rates, balance sheet and culture of customer value are genuinely superior to those of most retailers. The evidence from fiscal 2026 supports that conclusion. Net sales grew 10.2%, adjusted comparable sales increased 6.6% and the latest reported quarter delivered 15.2% EPS growth.

The harder conclusion is that a premium business does not make every valuation equally attractive. At roughly 43 times estimated fiscal 2026 earnings, COST is priced for continued double-digit profit growth and a future valuation that remains well above that of an average retailer. The stock's premium can survive if membership quality improves, comparable sales stay healthy and earnings compound near the low teens. If growth settles closer to high single digits or the market applies a lower multiple, the business may remain excellent while the stock struggles to match it.

That distinction is the central takeaway. Costco's operating model appears durable. The current valuation is less forgiving.