Shares of Berkeley , California-based Xoma dropped $ 1.49 or 27 percent , to $ 4 in Instinet trading .
Shares of Berkeley , California-based Xoma dropped $ 1.49 or 27 percent , to $ 4 in Instinet trading .
Shares in Berkeley-based Xoma lost 77 cents , or 14 percent , to close at $ 4.72 each in trading on the Nasdaq Stock Market .