About 40% of the S&P 500's revenue comes from abroad, where many countries are growing at a faster clip than the U.S. The S&P has a lot of powerful indirect exposures to the world economy, via emerging market and commodity demand. Commodity prices are very important to the energy, industrial and material companies. Business spending also has a lot of connections to global growth. And that's what drives S&P earnings.
David Bianco, chief US equity strategist, Bank of America Merrill Lynch "Experts agree: Get over your fear and get back into stocks", USA Today, December 17th, 2010