shares of davita inc dva shed 230 to 7299 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 davita inc closed 5182 short of its 52week high 12481 which the company reached on april 20th the stock underperformed when compared to some of its competitors thursday as unitedhealth group inc unh fell 198