The stock exchange council has concluded council member and former vice-chairman Choi Chen Po-sum breached exchange guidelines by failing to declare a conflict of interest.
Despite the ruling, Mrs Choi would receive no punishment apart from a mildly worded public statement which expressed concern at her actions but also said they were 'understandable'.
The council - which is responsible for policy-making at the exchange - has decided to review its five-year-old ethical guidelines for council members, with particular attention on the issue of conflicts of interest.
The council set up a committee in June to conduct an investigation into possible breaches of its code by Mrs Choi following her acquittal on bribery charges.
Mrs Choi was acquitted by the High Court in May on eight bribery charges after receiving $1.6 million for assisting in the transfer of exchange seats from On Wah United Securities to Nomura Securities (HK) and from Shing On Securities to Emperor Securities in 1994.
Mrs Choi was a council member and convenor of the membership committee at the time, but did not declare she had been paid for assisting in the transfer even though she was involved in the approval process.