Most of the companies that show up in IBD Big Cap 20 aren't "new" -- at least by IBD's definition. By "new" we mean those firms that went public within the past 15 years. Why is this relevant? IBD's research has found that newer companies tend to be the biggest winners in a new stock-market rally. New products or services generate big gains in revenue and earnings. Smart institutions accumulate shares in those types of companies. Yet it can take