93% probability Costco's reported August 2026 net sales grow at least +5% YoY — a floor sitting 5–9 points below its trailing +10–14% run-rate. May 2026 was +14.5% YoY; the 39-week YTD ran +10.0%. Resolves early September 2026 via Costco's monthly sales release.
Costco May 2026 net sales grew +14.5% YoY and the 39-week fiscal YTD ran +10.0% (investor.costco.com). The +5% bar sits 5–9 points below that trailing run-rate — a structural cushion. Source: Costco Wholesale monthly net-sales release (investor.costco.com; SEC 8-K), resolves early September 2026.
We lock a binary claim: Costco's reported August 2026 net sales (per its monthly net-sales release / SEC 8-K, early September 2026) grow at least +5% year-over-year versus August 2025. Confidence 93%.
Costco's monthly net sales have run +10–14% YoY through fiscal 2026 (May +14.5%; 39-week YTD +10.0%), powered by membership growth, traffic, and e-commerce. Our scored bar of +5% is deliberately set well beneath that run-rate, so even a soft month or a calendar/shopping-day shift clears it. Confidence is 93%, not higher, because a single month can swing on comparison-week timing and gasoline-price deflation (gas is in the net-sales line). Resolves against the reported August 2026 net-sales figure.
RAOSCAFF locks P-77 on 2026-06-23, before Costco reports August sales. The scored floor is +5% YoY total net sales — far below the trailing +10–14% run-rate — so the call survives a sharp single-month deceleration.
Floor call only — the scored threshold is +5% YoY; the trailing double-digit upside is open and not scored.