Chan added that the banker's actions had also seriously undermined the integrity of the financial markets.

Du, who earned a bonus of more than $2 million in the year before his offences, was fired by Morgan Stanley after the deal was discovered and fled to his native Beijing.

Hong Kong's Securities and Futures Commission froze millions of US dollars of his assets in the territory as an investigation into his share dealings was launched.

In a bizarre twist, he was only brought to justice after being arrested last year when he flew back to the city to collect a painting and an air purifier from his flat.

Hong Kong introduced a law against insider dealing in 2003 and has secured 10 convictions and six jail terms so far. Du's case involves the largest sums to date.