You shouldn't own common stocks if a 50 per cent decrease in their value in a short period of time would cause you acute distress.
Warren BuffettBen's Mr. Market allegory may seem out-of-date in today's investment world, in which most professionals and academicians talk of efficient markets, dynamic hedging and betas. Their interest in such matters is understandable, since techniques shrouded in mystery clearly have value to the purveyor of investment advice. After all, what witch doctor has ever achieved fame and fortune by simply advising 'Take two aspirins'?
Warren Buffett