shares of costco wholesale corp cost shed 406 to 46391 thursday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 249 to 389575 and dow jones industrial average djia falling 225 to 3320222 this was the stocks second consecutive day of losses costco wholesale corp closed 14836 short of its 52week high 61227 which the company achieved on april 7th the stock underperformed when compared to some of its competitors thursday as amazoncom