Costco Wholesale (COST -1.09%) passed $1,000 a share on Dec. 11, reaching a new all-time high and pushing its market capitalization past $440 billion. Costco's stock price is up big this year, but its earnings aren't growing that quickly. Costco's valuation now resembles a growth stock, not a value or dividend stock.Let's determine whether Costco is worth its growth stock premium, or if the risks outweigh the potential reward. A near-perfect business modelWholesale retail may lack the glitz and glam of high ...