David Jackson, the chief executive of Istithmar World who oversaw the investment firm’s most lavish purchases, has resigned as the company switches focus to managing existing assets.

Jackson, a former Wall Street banker, was one of Dubai World’s biggest hirings, helping to raise the profile of the government-owned conglomerate’s private equity arm with investments including a $942.3m (Dh3.46 billion) purchase of the luxury US retailer Barneys New York, and the Queen Elizabeth 2 cruise ship.

Andy Watson, Istithmar’s chief investment officer, has been appointed the acting chief executive, effective immediately. Mr Watson was a director with Barclays Capital, the investment banking division of Barclays Bank.

The National