Costco Is Down 10% in 6 Months While the S&P 500 Is Up 17%. Is Costco Too Cheap to Pass Up Under $900 a Share?

Costco shares fell 9.3% over six months, versus a 17.3% gain for the S&P 500, despite rising revenue, net income and free cash flow. Costco reported a 92.3% U.S. and Canada membership renewal rate and 3.8% paid-membership growth, but its valuation remains elevated: 44.3x trailing earnings and 43.6x trailing free cash flow. The article views Costco as a viable long-term buy-and-hold holding, while warning that tariff and diesel-cost pressures challenge retailers and that Costco shares are still not cheap.

Analysis

Costco: premium durability versus valuation risk

The key market question is whether membership economics can keep supporting Costco’s valuation premium—not whether near-term sales remain resilient. Membership income and renewal behavior may buffer merchandise-margin pressure, but that buffer is not unlimited: passing tariff and freight costs through risks weakening the value proposition, while absorbing them risks slower earnings conversion. Watch renewal rates alongside comparable sales and gross margin; renewal alone can lag changes in customer behavior.

The relative valuation is not a clean signal by itself. Costco’s premium may persist if investors prize predictable membership cash flows, while Walmart may capture value-seeking demand with a different mix and operating model. The P/FCF comparison is especially worth verifying against cash conversion and working-capital swings before treating it as evidence that either stock is cheap. If consumers trade down more broadly, Target and Best Buy could face greater discretionary-demand exposure; grocery competitors such as Kroger may be relatively defensive, though they do not replicate Costco’s membership model.

Over days, sentiment and positioning can matter more than fundamentals. Over 1–3 months, tariff pass-through, freight costs, and quarterly margin/traffic data are the catalysts. Over 6–18 months, the test is whether membership growth and renewal sustain earnings quality without sacrificing the price gap that attracts shoppers. The contrarian case against a reflexive short: a weaker consumer could reinforce warehouse value appeal. The thesis fails if Costco maintains renewal and traffic while margins stabilize; it strengthens if comparable sales or renewal weaken alongside margin compression.

Key Decisions for Investors

• Avoid treating the share-price decline as proof of value; do not add to COST solely on lower trailing multiples while its premium remains dependent on durable membership economics.
• For a relative-value expression, consider a small, staged short COST / long WMT position rather than an outright COST short. Entry is more attractive after COST outperforms or its relative valuation widens; the trade risks being wrong if Costco’s traffic and earnings resilience reaccelerate. Size for basis risk, since the companies’ business mixes differ.
• Before adding to either leg, verify comparable-sales trends, renewal rates, merchandise gross margin, and cash-flow conversion. Reduce or exit the relative trade if COST sustains stronger operating metrics and the COST/WMT relative price trend turns decisively higher.
• Reassess over the next 1–3 months as tariff pass-through and freight costs appear in reported margins. A clear margin stabilization with intact traffic would falsify the near-term bearish case; weakening renewal or comparable sales combined with further margin pressure would be a stronger downside catalyst.