We recently published December Disappointments: 10 Big Names Troubled Early. WR Berkley Corp. (NYSE:WRB) is one of the worst performers of last week. WR Berkley fell by 14.12 percent in the past five trading days of the month as investors resorted to profit-taking following the week prior’s surge, while in a wait-and-see mode for more catalysts to spark trading. On Friday alone, WR Berkley Corp. (NYSE:WRB) lost as much as 7.7 percent following announcements that it sold a 12.5 percent stake to Mitsui Sum ...