First, investing based on “mean reversion” will be less compelling. Even though flatter distributions with fatter tails have means, the constituency for mean reversion investing will shrink as those means will be much less often realised in practice. A world where the realised return rarely equals the expected valuation creates a bigger demand for liquid, default-free assets; it also lowers the demand for more volatile asset classes such as equities. These shifts are already taking place.
Second, frequent “risk on/risk off” fluctuations in investors’ sentiment are here to stay. Investors, based on 25 years of rules of thumb that “worked” during the great moderation, thought they knew more about the distribution of risk than they in fact did. This led to overconfidence during the bubble. The crisis reminded investors that these rules of thumb are less useful, if not dangerous.With declining confidence in a reliable set of investing rules, markets have become more susceptible to overreactions to daily news and, are, therefore, more volatile. Just think of the number of triple-digit days in the Dow. Moreover, because of the complex and broader involvement, real and perceived, of governments in the economy, separating policy signal from noise, and execution versus intent, has become as important as – but harder than – forecasting the macro data.
Third, tail hedging will become more important. An understandable consequence of the crisis is less trust in diversification as the sole mitigator for portfolio risk. We are already seeing increased investor interest in tail hedging, though the phenomenon is still limited to a small set of investors.
Fourth, historical benchmarks and correlations will be challenged. In this new “unusually uncertain” world, many investors will need to fundamentally rethink the design of benchmarks and the role of asset class correlations in implementing their investment strategies. The investment industry is yet to give sufficient attention to this.
Finally, less credit will be available to sustain leverage and high valuations. Even apart from the inevitable response to regulatory actions aimed at derisking banks, a world of flatter and fatter distributions will reduce available supply of leverage to finance trades and balance sheet expansion.
(just sorting out different links gradually, I'll sleep a little more)