The materials collected also involve alleged purchases of goods, totalling about HK$8.4 million, from suspicious sources in 2009, as well as purported special bonuses, made to some former employees without any proper authorisation, totalling about HK$6 million, in April 2011.

"The board understands from the ICAC that the investigation relates to the former management of the company under the Prevention of Bribery Ordinance and that the group, the existing directors and senior management are not involved in the investigation," CY Foundation said in the announcement.

Saying that the relevant payments under those transactions had been fully expensed or written off in the company's financial statements in 2011-2012 and before, the firm believes the transactions had no further financial impact on the group.

Most of the employees, except two back office staff, who received the special bonuses have left the firm, it said. The company said the investigation has had no impact on its business.

CY Foundation's former chairman, Theodore Cheng Chee-tock, was sentenced to five months' imprisonment in October for deceiving the company's board of directors and shareholders by concealing his ownership of a Wan Chai property and getting the firm to buy it for HK$53.5 million in 2007.

Through a listed company in Australia, of which he was the chairman, Cheng bought the property, on the 17th floor of 200 Gloucester Road, for HK$42.2 million in 2006. He breached listing rules by concealing his interest in the property.

Cheng was also banned from serving as a director of a listed company for three years.

Co-defendant Philip Yu, who was found guilty of defrauding the company and money laundering involving HK$12 million, was jailed for seven months.

Trading of the firm's shares has been suspended since December 13 and will resume today.