Question: Who was behind the largest private share sale on record in the initial flotation of a supermarket chain owned by Jardine Matheson Holdings via its Dairy Farm International Holdings subsidiary?

Context paragraphs:
Cold Storage (supermarket): Cold Storage is a supermarket chain in Singapore, owned by Dairy Farm International Holdings.

History of Jardine, Matheson &amp; Co.: Jardine Matheson & Co., later Jardine Matheson & Co.  Ltd., forerunner of today's Jardine Matheson Holdings, was a Far Eastern trading company founded in 1832 by Scotsmen William Jardine and James Matheson as senior partners.  Trading in opium, cotton, tea, silk and a variety of other goods, from its early beginnings in Canton (modern day Guangzhou), in 1844 the firm established its head office in the new British colony of Hong Kong then proceeded to expand all along the China Coast.

Jardine Matheson: Jardine Matheson Holdings Limited, also known as Jardines, is a British conglomerate incorporated in Bermuda, with its primary listing on the Singapore Exchange.  The majority of its business interests are in Asia, and its subsidiaries include Jardine Pacific, Jardine Motors, Jardine Lloyd Thompson, Hongkong Land, Jardine Strategic Holdings, Dairy Farm, Mandarin Oriental Hotel Group, Jardine Cycle & Carriage and Astra International.

James Sassoon, Baron Sassoon: James Meyer Sassoon, Baron Sassoon, FCA (born 11 September 1955) became an executive Director of Jardine Matheson Holdings and of Matheson & Co. in January 2013.  He is also a director of Hongkong Land, Dairy Farm and Mandarin Oriental.  He is Chairman of the China-Britain Business Council.

Anthony Nightingale: Anthony John Liddell Nightingale CMG, SBS (traditional Chinese: 黎定基) (born 1947) is a Hong Kong businessman.  He spent his career with Jardine Matheson Holdings, a diversified business group focused on Asia, and served as managing director from 2006 to 2012.  He retired as Managing Director of Jardine Matheson in March 2012, but he still serves as a non-executive director of the company and other listed group companies.

Dairy Farm International Holdings: Dairy Farm International Holdings Limited is an Hongkongese retail company with its legal base in Bermuda.  A member of the Jardine Matheson Group, it is a major pan-Asian retailer involved in the processing and wholesaling of food and personal hygiene products in the Pacific region and in China.  Jardine Strategic, a publicly listed holding company, has an attributable 78% stake in the firm.  It is listed on the London Stock Exchange, with secondary listings on the Singapore and Bermuda stock exchanges.

Jardine Strategic Holdings: Jardine Strategic Holdings Limited (, , ) is a large company that holds stock.  It is a part of Jardine Matheson Holdings Limited, or Jardine's.  Jardine Strategic was a constituent of the Straits Times Index.

Ian Macgregor: Ian Macgregor (born c. 1937) is a British investment executive and chartered accountant.  He is the former chief investment officer of The Wellcome Trust, oversaw growth of nearly £1bn per annum over fifteen years, making The Wellcome Trust the then-largest foundation in the world (total assets valued at about £14bn at his retirement in 2000).  Regarded by many as the most successful investment officer ever seen in the not-for-profit sector, Macgregor was behind the largest private share sale on record: initial flotation of Wellcome Plc.

Wellcome: Wellcome (; Cantonese: "Wai Hong" in Hong Kong; in Taiwan) is a supermarket chain owned by Jardine Matheson Holdings via its Dairy Farm International Holdings subsidiary.  The Wellcome supermarket chain is one of the two largest supermarket chains in Hong Kong, the other being PARKnSHOP.  Wellcome also operates supermarkets in Taiwan and the Philippines under the Wellcome name.  The parent company, Dairy Farm, also has other supermarket interests in the Asia Pacific under different brand names.

James Matheson: Sir James Nicolas Sutherland Matheson, 1st Baronet FRS (17 October 179631 December 1878), born in Shiness, Lairg, Sutherland, Scotland, was the son of Captain Donald Matheson, a Scottish trader in India.  He attended Edinburgh's Royal High School and the University of Edinburgh.  He and William Jardine went on to co-found the Hong Kong-based trading conglomerate Jardine Matheson & Co. that became today's Jardine Matheson Holdings.

Supporting paragraphs: Ian Macgregor Wellcome
Answer: Ian Macgregor