On Company Longevity

Thanks to Tim Kastelle for telling me about this fascinating piece of work (PDF) by Professor Richard Foster of Yale University. Foster found that the average lifespan of a company in the S&P 500 index has decreased from 61 years in 1958 to just 18 years today. His estimation at the current churn rate is that by 2027, more than three-quarters of the S&P 500 will be companies that we have not yet heard of. Golly.