SRL for [to a barrier to American - style index arbitrage , the most popular form of U.S. program trading that seeks to exploit brief differences between prices of stocks in New York and the price of a futures contract in Chicago based on those stocks]: It all adds up [to a barrier to American - style index arbitrage , the most popular form of U.S. program trading that seeks to exploit brief differences between prices of stocks in New York and the price of a futures contract in Chicago based on those stocks] .
<unk>