Gina Francolla is the Senior Producer of Quantitative & Market Data Services at CNBC.
April is the best month to be in blue chips, if history is a guide.
Investors are celebrating the second strongest bull run since World War II.
Demand for small-cap stocks is increasing relative to established large-cap names.
With stocks up, short interest reached the highest level in 20 months, but some investors see the trend as a bullish sign.