** Shares of artificial intelligence firm Opyl OPL.AX rise as much as 10.5% to A$0.021, set for their best trading session since Dec. 4
** Stock hits highest level since Dec. 18
** Co announces joint venture with X Firm, based in the U.S. and London
** Says the collaboration to feature OPL's proprietary TrialKey platform
** Says the JV aims to expand co's brand presence and market penetration across Europe, the Middle East, Africa and North America
(Reporting by Sneha Kumar in Bengaluru)
((Sneha.Kumar@thomsonreuters.com))