Sovereign wealth funds, whose assets have now reached just under $5 trillion, are using their clout to make asset managers train the SWFs' staff in a move that could, in time, put asset managers out of a job.

SWF's assets under management reached $4.62 trillion at the end of last year, according to figures just published by data provider Preqin. The assets have risen in each of the last five years, according to Preqin's figures, from $3.05 trillion at the end of 2007.