The rise of the superstars

A small group of giant companies—some old, some new—are once again dominating the global economy, says Adrian Wooldridge. Is that a good or a bad thing?
Read more: http://www.economist.com/news/special-report/21707048-small-group-giant-companiessome-old-some-neware-once-again-dominating-global?source=Snapzu