Costco (COST) shares flagging in a narrow August range this month and respecting the top of monthly value area support at 540 as they closed above today and look ready to run to 558 which is an overhead VPOC that is untested from back in April when the stock made fresh all-time highs. COST has rebounded strong since the May low it made and is likely to move retail earnings reports this week. A close below 21 EMA near 530 is a good stop level.