The falling Dollar is boosting large-caps and they are outperforming small-caps. This makes sense because large-caps are typically multinational companies that derive a good portion of their revenue abroad. The Financial Times estimates that companies in the S&P 500 generate around 40% of their revenues abroad. These foreign earnings must be converted to Dollars and a strong Dollar translates into lower earnings. A weaker Dollar, on the other hand, helps the bottom line for companies that generate revenues abroad.