Raymond Kwok Ping-luen now faces four charges, the latest being a bribery charge and a count of conspiracy to commit misconduct in public office, according to the Post.
The elder brother, Thomas Kwok Ping-kwong, has been charged with an extra count of bribery, taking to three the number of charges against him.
The names of the brothers were added to existing charges that had been filed against three other defendants - Hui, SHKP executive director Thomas Chan Kui-yuen and former Hong Kong Stock Exchange official Francis Kwan Hung-sang.
The bribery charge against the brothers alleges that the five conspired to offer more than HK$11 million to Hui to induce him to remain favourably disposed to SHKP.
The extra count against Raymond Kwok alleges all five conspired to commit misconduct in public office when Hui allegedly committed misconduct as chief secretary by being favourably disposed to SHKP and its subsidiaries in return for HK$8.5 million.