It's not risky to stay on the sidelines when the market is so overvalued. This is what Warren Buffet is doing. Regardless of what you think of him, he is more sophisticated than we are. Hindsight is 20/20. The market also drops every 5-10 years by 30-50%. If you take a 50% loss even once, your money has to work way harder just to get you back to where you were before. I mean, you need to double your money to recover from a 50% downfall, which is way harder than you think and prone to another major drop. Therefore, it is worth exercising some caution in your investments. If returns look too good to be true, they probably are.