Is It Too Late to Buy Costco or Merck? Are These Defensive Stocks Overbought?

Costco is up 18.1% YTD and trades at a premium (trailing P/E 53x, forward P/E 50x); fiscal Q2 FY2026 revenue was $69.60B (+9.22% YoY), membership fees rose 13.6% to $1.355B with an 89.7% renewal rate, and the 50-day MA at $989 is highlighted as support. Merck is up 14.8% YTD (trailing P/E 17x, forward P/E 24x reflecting a ~$3.65/sh Cidara charge that trims 2026 EPS guidance to $5.00–$5.15); Keytruda generated $8.4B in Q4 (+7%) and Winrevair $467M (+133%), with PDUFA dates on Apr 7, 2026 and Sep 21, 2026. Recommendation: Costco is a momentum 'hold' or 'buy on dips' toward the $989 support; Merck offers more fundamental upside but investors must weigh a rising non-GAAP tax rate (23.5–24.5% in 2026 vs 14.4% in 2025) and Keytruda patent concentration risk.

Analysis

Costco’s membership flywheel creates unusually sticky revenue visibility that lets the market prize growth despite thin margins; that same predictability gives suppliers leverage to optimize volume but compresses their pricing flexibility, raising the chance of supplier margin squeeze becoming a replay risk if traffic growth slows. The stock’s momentum profile looks institutionally owned and crowded — meaning small macro shocks (a surprise CPI print or a 2s10s steepening) could trigger fast multiple contraction even without a fundamentals miss; monitor weekly fund-flow proxies and options open interest as early unwind signals.

Merck’s story is driven by idiosyncratic binary catalysts rather than broad market multiple expansion, so outcomes will be asymmetrical: positive regulatory or label wins re-rate consensus forecasts quickly, while tax or patent-related shifts will compress free cash flow and buyback capacity over multiple years. Because near-term EPS is depressed by non-recurring charges, the cleanest play is to separate operational earnings power from accounting noise — watch sequential gross margin, ex-charge FCF conversion, and regulatory readouts over the next 3–9 months to re-assess valuation runway.

Portfolio-level, these names are two different trade constructs — one a cash-flow-backed momentum name, the other a catalyst-driven biotech-like asymmetric. For retirement-oriented allocations, prefer structured exposures that monetize current carry and cap downside (covered calls, defined-risk spreads) rather than straight longs; for active strategies, use pair trades to neutralize beta and harvest idiosyncratic outcomes over event windows.

Key Decisions for Investors

• COST — Buy-on-dip equity: accumulate on a 5–8% pullback from recent highs with a 12-month target total return of ~10–15% and a tactical stop-loss at ~8% below entry; use position sizing to limit portfolio exposure to 2–3% of NAV given valuation sensitivity.
• MRK — Directional catalyst spread: buy a 6–9 month call spread (long nearer-term call / short higher strike) to capture upside from upcoming regulatory readouts while capping max loss to the premium; target asymmetric payoff (30–60% upside to limited downside).
• MRK/XLV pair — Idiosyncratic long vs sector hedge: go long MRK size X and short sector ETF XLV size to neutralize macro beta for a 3–9 month event window; this isolates pipeline/regulatory upside while protecting against sector-wide rotations.
• COST covered-call income — For retirement mandates wanting yield, sell 2–3 month slightly OTM covered calls against existing COST holdings to harvest premium and reduce downside breakeven by ~1–2% per cycle; be comfortable capping upside if the name gaps higher post-catalyst.