The asset management industry has succeeded in capturing as much as a third of the $3 trillion (€2.1 trillion) owned by the world's sovereign wealth funds, but they are becoming more selective on the firms they pick to run their money.

Fund manager and custodian State Street, that works for a number of sovereign wealth funds, surveyed 37 of these funds -- all holding more than $3bn. It found that the largest of them generally outsource around 25% to 30% of their capital to outside managers. Of the remainder, the smaller funds tend to outsource even more.