New Silkroutes Group chairman Goh Jin Hian and finance director William Teo Thiam Chuan have quit amid Commercial Affairs Department (CAD) investigations.
Dr Goh quit "to devote more time to his personal affairs", while Mr Tan stepped down "to focus on personal matters and to pursue other interests", the healthcare firm said late on Thursday night.
Earlier that morning, New Silkroutes announced that its auditor Deloitte & Touche had issued a disclaimer of opinion on the financial statements of the group for the financial year ended June 30.
On Sept 30, the company disclosed that Dr Goh, the son of former Singapore prime minister Goh Chok Tong, and Mr Tan were being investigated by the CAD over a possible offence under the Securities and Futures Act.
New Silkroutes said then that it understood that the alleged offence was false trading and market rigging to do with past share buy-backs and share acquisitions.
Dr Goh is also being sued by the judicial managers of an unrelated firm - oil trader Inter-Pacific Petroleum - over US$156 million (S$212 million) in losses it sustained due to his alleged breach of duties when he was its director.
His resignation as New Silkroutes non-independent and non-executive chairman comes just over a week after he quit as chairman of a separate listed company, Cordlife Group.
Cordlife announced, also late on Thursday and after the New Silkroutes filing, that Dr Goh had also resigned as an independent director with immediate effect.
Dr Goh was New Silkroutes chief executive from July 2015 until Oct 1 this year, when he took over as chairman in a move announced in July.
Mr Kelvyn Oo Cheong Kwan, the firm's former chief corporate officer and executive director, is also assisting with the CAD probe. He resigned from the company on Aug 1.