Well,market efficiency在经济学上分不同的层次……研究Market efficiency有几个
结论对投资比较有用:
1. small cap return Actually beat Big cap in a consistent way in a Long time
. Make sure diversify your portfolio into small cap. This means buy And
hold SPY as most people said here will not maximize your portfolio value in
the long way.
2. same applied to International diversification
3. Behavior Finance Can deviate the assumption of market efficiency in
traditional economics, which means market anomaly can persist for a long
time. So market momentum does exist which means technical analysis is
useful. Don'T think current PE is so high so it will regress to mean
shortly. It will Stay high even go higher in the near future