Program Trade Program trading is defined as a wide range of portfolio trading strategies involving the purchase or sale of 15 or more stocks having a total market value of $1 million or more. One example is index arbitrage. Index arbitrage is defined as the purchase or sale of a basket of stocks in conjunction with the sale or purchase of a derivative product, such as index futures, in order to profit from the price difference between the basket and the derivative product. Other examples of program trading strategies are liquidation of facilitation's, liquidation of EFP stock positions, and portfolio management, which includes portfolio realignment and portfolio liquidations. The NYSE's program trading statistics are aimed at assessing the impact of these transactions on the normal functioning of the market. Daily program trading activity is calculated as the sum of shares bought, sold, and sold short in program trades. The total of these shares divided by total reported volume then provides a percentage which illustrates the relative importance of program trading during the period in question. This method is not the only way to measure program trading. One alternative would be to examine buy programs as a percentage of total purchases; another would be to examine sell programs as percentage of total sales. A third alternative is to calculate program purchases and sales as a percentage of total purchases and sales or twice total volume (TTV).