Relatively low volatility with considerable reward for the lower levels of risk... Thanks to the 2008 recession, QE and the global markets struggling. It's funny how many throw a dart at the US stock board investors think they have it all figured out now.
The markets are cyclical... I'm no longer amazed but I'm worried for those all your eggs in the hottest basket investors. They love those lagging indicators and don't mind being late to the great performance party. Constantly chasing the hottest securities, but usually too late.
Although no one can predict markets, it's inevitable that a real correction or even bubble burst will occur at some point for any sector, industry or geographical area.
Be diversified... It's better to give up maximum potential upside for some level of stability when things get real volatile. Especially for folks within 10 yrs of retirement or within 10 yrs of needing the money.