HONG KONG, June 8 (Reuters) - Hong Kong's Court of Appeal has ruled in favour of a tribunal decision that partly upheld regulatory action imposed on the Hong Kong unit of Moody's Investors Service for a report on Chinese companies, Moody's said in a statement on Thursday.

Moody's Investors Service said last year it would challenge a March 2016 ruling by the Securities and Futures Appeals Tribunal (SFAT) upholding the securities regulator's claim that Moody's broke rules governing how regulated firms should behave when it published the report.

The case has been closely watched by the financial industry and corporate governance activists, as it is likely to redefine the limits on what can be written in research reports on public companies, potentially curtailing the activities of research firms in the financial centre. (Reporting by Michelle Price; Editing by Muralikumar Anantharaman)