shares of wr berkley corp wrb slid 144 to 6030 wednesday on what proved to be an allaround poor trading session for the stock market with the sp 500 index spx falling 070 to 389193 and dow jones industrial average djia falling 087 to 3187457 wr berkley corp closed 1669 short of its 52week high 7699 which the company achieved on december 1st despite its losses the stock outperformed some of its competitors wednesday as chubb ltd cb fell 341 to 18740 progressive corp pgr fell 478