Rule of Three

Name any industry and more likely than not you will find that the three strongest, most efficient companies control 70 to 90 percent of the market. Here are just a few examples:

• McDonald''s, Burger King, and Wendy''s
• General Mills, Kellogg, and Post
• Nike, Adidas, and Reebok
• Bank of America, Chase Manhattan, and Banc One
• American, United, and Delta
• Merck, Johnson & Johnson, and Bristol-Myers Squi...