Did Diversification Fail When We Needed It Most?

Ken French talks about diversification

Ken argues that the observation that correlations across asset classes went up recently is "probably a mis-perception". He argues that really what is happening is that the market component of risk became more significant, and to the extent that all assets have a market component, they will all be affected by this component.

However, at the end of the day, for an individual investor this is probably semantics. Pretty much everything went down!