For Kwok brothers, it appears mum knows best

"The board sets the company's strategies and ensures good governance, and the executive committee makes all major commercial decisions collectively," Sun Hung Kai said in a response to questions, while declining to comment on the trial. It is committed to the highest levels of governance, it said.

Fiona Wan, a spokeswoman for the Kwok's family trust, declined to comment about Kwong's control of the family fortunes.

Sun Hung Kai said recently the convictions of Thomas Kwok and executive director Thomas Chan have not affected its business and operations. Adam Kwok, Thomas's 31-year-old son, who had been appointed as an alternate director for his father when the latter was charged in 2012, was appointed as an executive director.

Shares rose the most in two and a half months on Tuesday when they resumed trading for the first time since the verdicts.

In cases where family members own a bulk of the company, outside shareholders are sometimes left out of the decisions.

Corporate governance norms are especially hard to attain at sensitive times such as the death of the patriarch or matriarch, and decisions are made behind closed doors, as heard in the trial of the Sun Hung Kai chairmen.

The Kwok family trust has the largest stake in Sun Hung Kai, co-founded in 1963 by the brothers' father, Kwok Tak-seng. Walter took over as chairman after his father's death until he was forced out in 2008 on the grounds of mental illness.

Walter said at the time he didn't have any such disorder and sued his siblings for libel, a case that was later dropped. He alleged that his brothers accused him of making unwise investment decisions and called him a liar, according to a court filing.

The defense of Thomas, 63, and Raymond, 61, against charges of corrupting Hui relied on their brother Walter's emotional and physical health.

Thomas Kwok said he struck an unwritten consultancy agreement with Hui in 2003 for HK$15 million, which was the highest ever paid to an adviser by the company. He testified the deal was concealed because Thomas promised his mother he wouldn't do anything to provoke Walter, who was opposed to hiring Hui at the time.