I have always considered this comparison, and I do think the S&P 500 is immune from what the Nikkei experienced. The reason is that we're talking about U.S companies and the U.S economy. Warren Buffett always says invest in U.S. businesses with confidence. When he says that, I believe him.Nikkei 225, and don't think the S&P500 is somehow so special that it's not immune.