Historically aggregate insider trading has been a good predictor of subsequent market direction.

• An increase in Buy Ratio generally produces an increase in the stock market index.
• The strength of the corelation increases with the aggregation period, thus a 12 Months Buy Ratio is a better predictor than a 1 Month Buy Ratio.

Definitions:
Buy Ratio: # Net Buyers / (#Net Buyers + #Net Sellers)
Net Buyers: companies where insider buying exceeds insider selling.
Net Sellers: companies where insider selling exceeds insider buying.