Send us a textA study by McKinsey found that the average life-span of S&P 500 companies has fallen from 61 years in 1958 to less than 18 years today. McKinsey predict that, by 2027, 75% of the companies currently included in the S&P 500 will have disappeared.So, What happens to these companies? Well, many will be bought- out, merged, and some will even go bankrupt like Lehman Brothers and Worldcom did. Some companies keep on going. General Electric, Exxon Mobile and Procter & Gamb...