With intertemporal smoothing of returns, good investment years subsidize bad investment periods, with a  18  The very hypothesis of ergodicity of most economic and financial time series has been questioned from time to time (se, for example, Davidson, 1991) and becomes hard to believe in crisis periods.
19  For the long-standing debate on the pros and cons of equities compared with bonds and the asset allocation of long-term investors, see Campbell and Viceira (2002), Siegel (2002), Bodie and Clowes (2003), Merton (2006) and Blake, Cairns and Dowd (2008). BIS Review 148/2008  7  potential redistribution of investment income across plan members.