Dubai: The Abu Dhabi Investment Authority (Adia), one of the world’s biggest sovereign wealth funds, confirmed on Monday that the global head of its infrastructure investments group had left the fund for personal reasons.

Chris Koski joined Adia in 2007 from the Canadian Pension Plan Investment Board to set up its infrastructure team, and became the go-to person for bankers and funds pitching infrastructure-related investments to the Abu Dhabi fund, sources familiar with the matter said.

Under Koski, Adia picked up minority stakes in some of the world’s leading infrastructure projects by co-investing with large institutional investors such as pension funds and other sovereign institutions.

“Adia’s infrastructure team was very active and Koski was spearheading the show,” one banking source said, speaking on condition of anonymity because he was not authorised to talk to media about the issue.

A spokesman for ADIA said a search process was underway to find a replacement for Koski.

In its 2011 annual review, Adia said the focus of its infrastructure team was mainly in developed markets. It was looking for assets in sectors including utilities, such as water, gas and electricity distribution and transmission companies, as well as transport infrastructure, such as toll roads, ports, airports and freight railroads.

The fund allocates between 1 and 5 per cent of its portfolio to infrastructure investments. It does not disclose the size of its total assets but is widely believed to hold assets of $400-$600 billion.

In 2011, one of Adia’s subsidiaries was part of a consortium that agreed to acquire a 24.1-per cent stake in Gassled — Norway’s gas transmission pipeline system. Among listed equities, the team acquired slightly more than 5 per cent of MAp Airports, now known as Sydney Airport Holdings Ltd, an Australian company which owns stakes in the Sydney, Brussels and Copenhagen airports.

Adia also agreed to buy a 9.9-per cent stake in Thames Water, Britain’s largest water and waste water firm, from a consortium of investors led by Australian investment bank Macquarie.

In the review, ADIA said it combined its infrastructure and real estate teams as one unit to improve efficiency and better align investment teams and resources. Majed Salem Khalifa Al Romaithi is the executive director in charge of the division.

Adia returned 6.9 per cent on an annualised basis over a 20-year period as of December 31, 2011, a slight drop from the 7.6 per cent it posted in 2010. On the same basis, the fund returned 8.1 per cent over a 30-year period, similar to 2010.