JBPB & Co, the accountancy firm formerly known as Grant Thornton, is suing six former partners for HK$640 million.
A High Court writ filed on Wednesday claims the six partners conspired to 'injure the interests' of the firm and did not act honestly to advance its business interests.
The defendants include Mark Fong Chung, a former president of the Hong Kong Institute of Certified Public Accountants, and Daniel Lin Ching-yee, the managing partner of Grant Thornton Jingdu Tianhua.
JBPB is seeking damages of at least HK$640 million to the commercial value of the firm's practice. Damages are also being sought for loss of clients, loss of profits and loss of goodwill.
Grant Thornton will cease operations at the end of the month. More than 600 accountants, including chief executive Patrick Rozario, are crossing over to rival BDO.
The defendants have left Grant Thornton and at least four of them are employed by Grant Thornton Jingdu Tianhua, a new member firm under Grant Thornton International. They are also former partners of accountancy firm Moores Rowland who joined Grant Thornton with 80 other staff in July 2007.