Among the stock activity stories for Thursday, Dec. 17, from AP Financial News:

LOS ANGELES (AP) _ Shares of Hovnanian Enterprises Inc. tumbled after the homebuilder's chief executive said he doesn't anticipate the company will turn a profit before 2011.

NEW YORK (AP) _ Shares of A123 Systems Inc. rose after the battery maker said it is planning a Chinese joint venture with General Motors Co. partner SAIC Motor Corp. to supply batteries for electric and hybrid vehicles.