He owned the Goodwood Group of boutique hotels in London and Singapore and was the largest single shareholder of the British bank Standard Chartered.
The bulk of his fortune came from shares in Standard Chartered, which he bought up in the 1980s to help thwart Lloyds Bank's proposed acquisition which many financiers deemed hostile.
The Goodwood Park Hotel in Singapore, built in 1900, is a restored historic landmark.
Around the period of his death in 2004, Khoo was ranked as the 108th richest person in the world by the business magazine Forbes .
Khoo's estate has donated S$80 million to Duke-NUS Medical School.