Many investors (including the author) were caught off guard by the economy’s surprising earnings growth over the last several years. Earnings of S&P 500 companies have grown more than 20% during the last two years, and they are expected to climb another 8% in 2006. This astonishing growth has exceeded the Gross Domestic Product (GDP), which topped out at 4.6% in 2004 and has grown at a slower rate since. Contrary to common perceptions, corporate earnings growth historically stays in line with GDP growth.