Could Investing $10,000 in Costco Make You a Millionaire?

Costco continues to post solid operating results, with same-store sales up 5.9% in fiscal 2025 and 7.4% in Q2 2026, supported by 82.1 million paid memberships and an 89.7% renewal rate. However, the article argues the stock's $456 billion market cap and 53.5x P/E make it too expensive for outsized future returns. The piece is more of a valuation caution than a fundamental warning, suggesting investors keep Costco on a watch list rather than buy aggressively.

Analysis

The market is treating Costco as a defensive compounder, but the real issue is not business quality—it is duration risk. At >50x earnings, the stock is implicitly discounting years of near-flawless execution, meaning any slowdown in membership growth, basket mix, or renewal economics will hit multiple expansion first and fundamentals second. In other words, the downside catalyst is less a recession than a re-rating if investors decide stable growth deserves a lower scarcity premium in a higher-rate world.

The second-order winner from Costco’s resilience is not necessarily the stock itself, but adjacent vendors and private-label supply chains that benefit from persistent traffic even in soft demand. That said, the company’s scale now creates a self-limiting base effect: even strong absolute gains translate into modest incremental value creation, while smaller high-quality retailers can outperform on a growth-to-valuation basis. The market is effectively paying large-cap software multiples for a low-teens compounder, which is a poor setup if growth normalizes even slightly.

For NVDA and NFLX, the linkage here is mostly sentiment and factor rotation rather than direct fundamentals. COST’s expensive defensive profile can serve as a proxy for crowded quality ownership; if that trade unwinds, capital may rotate into higher-beta secular growers or into AI/streaming names with better long-run earnings elasticity. The contrarian point is that Costco’s premium is not irrational if the macro remains sticky and consumers keep trading down, but that premium is already doing most of the work.

Near term, the stock is more likely to underperform than collapse: expect relative weakness over the next 1-3 quarters if rates stay elevated and the market broadens. The cleanest risk is not an earnings miss, but any evidence that traffic gains are being bought with margin dilution or heavier promotions, which would compress both earnings quality and multiple simultaneously.

Key Decisions for Investors

• Short COST vs long XRT or long a basket of lower-multiple defensive retailers over the next 1-3 quarters; thesis is valuation mean reversion if Costco's premium compresses faster than peers' earnings deteriorate.
• Sell COST upside calls 2-4 months out against a core short-dated long or flat position; collect elevated implied volatility while capping exposure to a slow bleed rather than a breakout.
• Rotate incremental capital from COST into NVDA on any broad quality selloff; NVDA has better earnings torque and a more favorable growth-to-valuation setup despite higher headline volatility.
• Use COST as a watch-list name only unless it de-rates 15-20% or earnings growth re-accelerates meaningfully; at current multiples, margin of safety is too thin for new longs.
• If seeking defensive exposure, prefer a basket of lower-P/E grocers or discount retailers over COST for the next 6-12 months; same resilience, less valuation risk.