Investors will suffer if their portfolio is too concentrated. You own a big retailer, a major restaurant chain, an airplane maker, a computer and phone maker and a chemical company. But for individual investors saving for a specific goal, such as retirement, the one basket rule makes zero sense. Another, even worse example of a precipitous price decline is Biogen (BIIB), which, like Boeing, is an S&P 500 stock. But as the recent experiences of Boeing and Biogen illustrate, company-specific declines can have an outsized effect on investors who fail to diversify properly.

Source: Ethiopian News March 26, 2019 15:33 UTC