A number of industries have experienced rapidly increasing global concentration in recent years: commercial aircraft (led by Boeing and Airbus), steel (led by Mittal Steel), beer (led by SAB-Miller, Anheuser-Busch-Inbev, and Heineken), commercial banking (led by Citigroup, HSBC, Bank of America, Royal Bank of Scotland, and Banco Santander), defense equipment (led by Lockheed Martin, Northrop Grumman and EADS), and delivery services (led by UPS, Federal Express, and Deutsche Post/DHL).
For each industry, are economies of scale the major reason for increasing concentration? If so, identify the sources of economies of scale.
If not, how can increasing global concentration be explained?