SEOUL (Reuters) - Samsung Electronics 005930.KS Chairman Jay Y. Lee was found not guilty of accounting fraud and stock manipulation by a Seoul appeals court on Monday, in a case about a 2015 merger that prosecutors said was designed to cement his control of the tech giant.

The case has highlighted long-running legal risks for Lee, who faces growing questions about his ability to lead Samsung Electronics, the world's top memory chip and smartphone maker grappling with growing competition and lacklustre stock prices. A lower court last year cleared Lee of all charges including stock price manipulation and accounting fraud related to a 2015 $8 billion merger between two Samsung affiliates - Samsung C&T and Cheil Industries. Prosecutors later appealed to the Seoul High Court, seeking a five-year jail term this time, citing a separate ruling in August that said Samsung BioLogics, an affiliate of Cheil Industries, breached accounting standards by overstating its assets to justify the merger. Lee has denied wrongdoing, saying in court last November, "I never intended to deceive or damage investors for personal gain".

It was not immediately clear whether the prosecution would decide to appeal the decision at the Supreme Court.