Cardinal Joseph Zen and five others were on Friday found guilty of failing to register their fund for protesters as a society.
The now-defunct 612 Humanitarian Relief Fund raised money to pay the legal and medical fees of protesters between July 2019 and October 2021.
West Kowloon principal magistrate Ada Yim ruled that the defendants failed to register the fund in a timely manner in accordance with the Societies Ordinance.
Zen and other former fund trustees - former lawmakers Margaret Ng and Cyd Ho, singer Denise Ho and scholar Hui Po-keung - were each fined HK$4,000.
Former fund secretary Sze Ching-wee was ordered to pay a HK$2,500 penalty.
Ng said outside court that because of the court's lengthy judgement, the defendants would need some time before they could decide whether to pursue the matter further.