He is the eldest son of the late Ng Teng Fong, the Singaporean real estate billionaire. Forbes listed the two as the 30th richest people in the world in 1997. As of July 2017, Robert, along with his brother Philip Ng, has an estimated net worth of $9.7 billion.
Ng was speculating in futures contracts on the Hong Kong Futures Exchange through two Panamanian-registered companies when the October 1987 global stock market crash began; his paper losses reportedly reached HK$1 billion. At first, Ng refused to pay, claiming to be protected by the limited liability of the companies through which he had traded. This led to the collapse of the futures exchange; trading was also halted on the Hong Kong Stock Exchange for four days. An investigation by the Commercial Crime Bureau of the Royal Hong Kong Police revealed that Ng had avoided required margin calls through collusion with one of his brokers. However, in the end, no charges were laid against Ng because the colonial government of Hong Kong felt that prosecuting him would pose a risk to overall market stability. Instead, a deal was worked out which saw Ng repay HK$500 million, with Hong Kong taxpayers providing the rest of the funds needed by the Exchange through a government bailout. Ng reportedly lost a total of US$250 million in his various investment holdings as a result of the crash.
In June 1995, Ng took over as chairman of Yeo Hiap Seng (YHS), a Singapore-listed food and beverages company which had lost US$3.2 million in its previous year of operation. His chairmanship came at the same time as his family increased its stake in the company to 24.9%, just short of the 25% threshold above which they would be required by law to make an offer to buy out all other shareholders. This marked a step forward in his fight with Malaysian billionaire investor Quek Leng Chan for control of YHS and its land holdings in Singapore's Bukit Timah district, which could be worth billions of dollars were they redeveloped into residential real estate. In the end, Ng and his father were able to successfully take advantage of squabbles within the Yeo family to buy up 86% of YHS' stock. Their battle to gain control of the company was later described as "one of the most colourful take-over struggles in Singapore history" and led to YHS' transformation from a food company to a luxury real estate developer.
The Sino Group also spun off their hotel interests into a new company, Sino Hotels, in that year; Ng became chairman of the board of the new company as well from its inception. In early 1997, under Ng's direction, Sino Hotels made several acquisitions, including an 80% stake in the local branch of the Conrad Hotel for HK$2 billion. Ng also predicted that office properties would perform well during that year. For the latter six months of that year, Sino Hotels reported a 66% fall in net interim profits and 80% fall in operating profit, which Ng attributed to lower contributions not just from hotels but from the company's Fortune chain of Chinese restaurants as well. However, the Conrad proved to be a resilient investment, with the average room rate increasing by 14.7% during the months in question.
As of 2009, Ng is the director of a number of subsidiaries and associated companies of Sino Group:
- Chairman of Tsim Sha Tsui Properties Limited, parent company of Sino Land
- Chairman of Sino Hotels (Holdings) Limited
- Independent non-executive director of The Hongkong and Shanghai Hotels, Limited
- Director of the Real Estate Developers Association of Hong Kong
- Member of the 11th National Committee of the Chinese People's Political Consultative Conference
- Non-executive director of SCMP Group Limited from May 2004 to May 2007
- Chairman of the Singapore Chamber of Commerce (Hong Kong) since its inception in 1995
Due to his business positions, Ng wields a significant amount of power under Hong Kong's functional constituency system. In 1998, he and companies owned by Sino Group controlled roughly 3–4% of the votes in the real estate constituency, and an additional two votes in the tourism constituency. The voting power he wields through this system has been described as equivalent to anywhere from 6,100 to 15,940 votes in geographic constituencies, which has led to criticism by the Hong Kong Human Rights Monitor.
Ng has spoken out in support of the "Application List" system for the sale of government land and in 2008 remained publicly optimistic about the prospects for the Hong Kong property market.
Ng is married to Yeoh Saw Kheng (楊素瓊) a fellow ethnic Chinese of Cantonese descent, who is the 3rd daughter of Dr Yeoh Ghim Seng, the former Speaker of Parliament of Singapore
Ng's eldest son Daryl Ng Win Kong (黃永光) was born in 1978. He holds Singaporean citizenship and joined the mandatory military service; at the same time, he speaks passionately about his Hong Kong root and childhood spent in Hong Kong, reminding that he was born at Queen Mary Hospital and attended Diocesan Boys' School rather than an international school in his youth. He later studied in the United States, where he graduated from Columbia University in 2003, and after two years as a project manager in Sino Group was appointed an executive director in 2005. He is generally expected to be his father's successor. In 2007 he began to take a more public role, first appearing at a land auction with his father in October that year. During his first time speaking with the media about the property market in March 2008, he spoke only briefly. Since then he has spoken on various occasions and has taken up public duties. He advocates sustainability and heritage, and champions projects like mini hydro power, food waste management, Tai O Heritage Hotel in Hong Kong and The Fullerton Heritage in Singapore. He is married with a son and a daughter. Ng also has two younger sons David Ng Win Loong (黃永龍) and Alexander Ng Win Yew (黃永耀).
Ng's eldest daughter, Nikki Ng Mien Hua (黃敏華) attended Yale University as an undergraduate, and went on to receive a master's degree from the University of London's School of Oriental and African Studies. She was later appointed to the position of general manager of the Sino Group. Her activities outside of Sino Group include membership of the 11th Qingdao Chinese People's Political Consultative Conference. Ng also has two younger daughters Jeanne Ng Mien Yi (黃敏儀) and Christine Ng Mien Yin (黃敏音).
Beginning in the late 1990s, the family became more active in the Hong Kong Jockey Club. Daryl, Nikki, and Jeanne own four horses between them, while the elder Ng himself owns eight and his wife one. At one point in 2002, Ng was said to be interested in joining the 12-member board of stewards of the Hong Kong Jockey Club; however, some of the club's 200 voting members objected due to Ng's conduct during the futures market collapse in 1987.
Both Daryl and Nikki are members of the five-person board of the Hong Kong Heritage Conservation Foundation. The HKHCF was initially set up under the name Nice Brilliant Limited in December 2007, and changed its name in March 2008. In October 2008, the HKHCF made a bid for the revitalisation of the Old Tai O Police Station, with the intention of turning it into a boutique hotel; legislators looked suspiciously at the foundation's ties to the Sino Group, with Fernando Cheung accusing them of being a "one-man NGO" set up for business purposes rather than social service. The HKHCF's bid was eventually successful; the project, Tai O Heritage Hotel, was opened on 1 March 2012, with an estimated cost of HK$64.9 million.
Ng's father Ng Teng Fong died in Singapore on 2 February 2010 at the age of 82 after suffering a cerebral haemorrhage. Ng said his father was "always optimistic and hardworking".