Among the stock activity stories for Thursday, July 19, from AP Business News:
— International Business Machines Corp.'s stock had its biggest gain in six months after saying its stream of rising profits will go on, even in the shaky economy. IBM was the top performer among the 30 companies that make up the Dow Jones Industrial average.
— Shares of Ceradyne Inc. fell after a Benchmark Co. analyst lowered ratings on the ceramic products manufacturer, citing the potential for sales to decline because of slower global economic growth.
