I spoke yesterday about a potential pull back to the wedge line and so far it is showing signs of that now, the 0.5 Fib at $503 would be the perfect level to pull back to but that would almost be too good to be true so please do not wait for that level if you really like $COST and have intentions to hold this for long term.
I think anywhere around the 0.38 Fib at $510 would be a great place to add to get full value of the upside potential here.