Asset managers earn a markedly higher advisory fee from active investment strategy and rightly so, since given the relatively more trading of assets, active investing incurs higher transaction costs but more importantly because active management relies on the skill of the asset manager which needs to be duly compensated with a higher advisory fee.
We still do not know how much of this money was actually transferred from the six countries under study (since the Nazis were very active in looting the assets they could find, and especially wanted to lay their hands on foreign securities).
On the opposite side of the spectrum, numerous active management techniques allow you to shuffle assets and allocations around in an attempt to increase overall returns.