Share prices are up 47.6%, roughly double the broader market's 24.8% spike so far this year and well above main rival Walmart's (NYSE: WMT) flat performance this year. Costco (NASDAQ: COST) stock has raced back into Wall Street's good graces in the final weeks of 2021. Higher membership fees and dividends may be coming Costco is famously careful about raising prices for merchandise even in inflationary times like these.