I think Fred is not telling the entire story with this bubble question/explanation. From a macro perspective I personally don't think there is a bubble, part of

I think Fred is not telling the entire story with this bubble question/explanation. From a macro perspective I personally don't think there is a bubble, part of the rationale is explained in Fred's post. What I think Fred is avoiding is the company-specific micro-view. In that case, I think "yes", many late stage startups seem to be over valued, just by applying Fred's yield logic (and growth-risk accounted for). Zynga was one of those companies (and obviously) we never heard how overpriced this was at IPO from Fred. The valuation of these over valued startups seem to be driven by (i) increase in capital/competition from funds, (ii) eagerness by public markets to jump on the tech/startup bandwagon, and (iii) unrealistic "believe" that double-digit growth is sustainable for years to come.