** Hong Kong shares of Chinese search engine leader Baidu 9888.HK jump as much as 12% to HK$99.6, their highest since Oct. 14, on course for second consecutive session of gains
** Stock on track for its biggest one-day pct rise since March 2023, if gains hold
** Baidu said on Thursday it would make its artificial intelligence chatbot Ernie free starting April 1, citing improved technology and reduced costs
** The AI service will be accessible at no cost to all users on both desktop and mobile platforms, Baidu said in a WeChat post
** U.S.-listed stock rose 4.3% on Wednesday
** Hong Kong stock fell 28.8% last year, U.S. shares dropped 29.2%
(Reporting by Donny Kwok)
((donny.kwok@thomsonreuters.com))