COST · PEAD → 7

Costco reported Q4 FY2026 EPS of $6.60 on 2026-09-24, beating the $6.48 consensus by $0.12 (+1.85%).

Print-day reaction was -0.91% versus the prior close, a modest sell-the-news dip despite the EPS beat. The overnight gap to T+1 open extended the weakness, adding another -1.06% to the downside. Over the following two trading days, COST drifted +0.20%, clawing back a fraction of the initial decline but leaving the 3-day trajectory essentially flat. Cumulative abnormal return of +2.67% versus SPY.US sits just below the PEAD long threshold, rendering a none verdict; the holding window runs through 2026-12-22.