Should You Buy Costco Stock Before Sept. 24?

Costco is scheduled to report fiscal Q4 earnings on Sept. 24 after August comparable sales rose more than 8% companywide and about 9% in the U.S. Despite solid operating momentum, the article argues the stock's nearly 50x trailing-earnings valuation limits upside and raises the risk of a post-earnings decline. Costco shares were up roughly 6% year to date versus about 12% for the S&P 500, with economic uncertainty and potential rate hikes cited as additional headwinds.

Analysis

The relevant setup is not whether Costco can post healthy sales, but whether it can deliver enough incremental membership-fee, merchandise-margin, and renewal-rate upside to support a premium multiple through fiscal 2027. Costco’s traffic-led model is relatively insulated from discretionary softness, but that also leaves little room for a conventional same-store-sales beat to drive a rerating; investors will focus on core U.S. comp ex-gas/FX, membership income growth, digital profitability, and gross-margin progression. A solid-but-in-line print is therefore more likely to reset the multiple than change the underlying earnings trajectory over the next 1-3 months.

Second-order, a Costco valuation reset would not necessarily be bearish for mass retail broadly. WMT is better positioned if consumers trade down from higher-ticket discretionary categories, while BJ offers a lower-multiple warehouse-club read-through and potentially greater upside if membership economics remain durable. Conversely, TGT remains exposed to a less defensive discretionary mix and would not receive the same traffic-quality benefit from a resilient Costco report.

The contrarian case is that the market may be underestimating operating leverage from membership pricing, ancillary services, and improved shrink/freight comparisons over the next 6-18 months. That thesis requires evidence that incremental sales are converting into EBIT faster than consensus expects; otherwise, a high-quality business can still produce flat returns as earnings grow into valuation. Falsification for a tactical short is upward guidance paired with clear acceleration in membership income or margin, while a break in traffic or renewal trends would turn a valuation concern into a more fundamental downside case.

Key Decisions for Investors

• Do not add outright COST exposure ahead of earnings solely on sales momentum; wait for the report’s margin, renewal, and forward-guidance details. A post-report decline without a cut to these KPIs would be a better long entry than pre-event chasing.
• For a 1-3 month valuation mean-reversion expression, consider a small long BJ / short COST pair, sized beta-neutral. The thesis is that comparable warehouse-club demand should narrow the relative valuation gap; exit if Costco guides to material membership-income or EBIT-margin acceleration.
• Use WMT as the preferred defensive retail long rather than COST if seeking consumer-staples-adjacent exposure through year-end: WMT has broader trade-down optionality and less dependence on a premium valuation sustaining. Reassess if Walmart’s discretionary general-merchandise trends deteriorate or food inflation reaccelerates materially.
• Before initiating any COST options position, obtain implied volatility versus its prior earnings moves and consensus estimates for core comp, gross margin, and EPS. If implied move is above the historical realized move, a defined-risk bearish call spread may be preferable to directional puts; if not, there is no compelling volatility trade from the supplied data.