Interesting. I partly agree. Valuation by itself is never a good reason to go short. But an excessive valuation is a tailwind that helps the shorts. Valuation plus a declining business or a business showing early signs of trouble is indeed a good starting point for short ideas. Also, I'll point out that there are more types of shorts than frauds and expensive stocks. Secular decliners, flawed business models, and growth stories starting to break also factor into the picture. In the latter case, an excessive valuation is like downside leverage when the growth story starts to break. Otherwise an interesting article. Thanks for posting.