Nothing sets a regulator's nerves on edge quite like the thought of the public investing in hedge funds. It carries what the managers themselves might call asymmetric risk: get it right and the complexity of the subject means few non-specialists will notice; get it wrong and resignations will fly.

It's the sort of dilemma to give sleepless nights to the most stout-hearted investment professionals. But to their credit, and to the hedge fund industry's benefit, regulators across Europe have been inching open their markets.