"[Is] this more evidence that pensions (and sovereign wealth funds) are inflating an infrastructure bubble? ... [W]hy are the Ferrovials and Hochtiefs of this world selling their stakes in airports to large pension funds and sovereign wealth funds? Is it really part of a 'diversification strategy' or are they worried of the changing regulatory landscape? ... These are long-term investments which make perfect sense to pensions from an asset-liability standpoint. But infrastructure assets carry significant risks, the most important one being regulatory risk."