Anita Chan Lai-ling, the widow of philanthropic educator Chan Shu-kui, had allegedly been pressed to sign accumulator contracts by a banker in the two days before she died in October 2007.
Shine Grace Investment - which was previously run by Chan - is suing Citibank and one of its vice-presidents, Hailey Mak, for damages in the Court of First Instance.
Yesterday, Mr Justice William Stone gave a judgment on a pretrial issue regarding the preparation of the defence case and details surrounding Shine Grace's claim were revealed.
Justice Stone said the central claim concerned nine accumulator contracts that resulted from dealings between Mak and Chan at the Adventist Hospital on October 17, 2007.
The contracts facilitated the purchase of shares in mainland companies listed on Hong Kong's main board in mid-October, particularly October 15 and 16.
The judgment said the Shine Grace claim was for the 'very substantial losses' incurred by the transactions made under the contracts.