      Billions of dollars are traded each week based on the fluctuatingpremium of the futures versus the cash value. Fair Value is the price atwhich investors are indifferent between buying stocks or buying futures. Inother words, the "value" is the same, or "fair." If the futures contractbecomes overvalued in comparison to the cash index, arbitrageurs willsimultaneously sell the futures contract and buy the cash index (aportfolio of all or the majority of the stocks in the S&P 500 index) tolock in a riskless profit. If the futures contract becomes undervalued incomparison to the cash index, arbitrageurs will do the opposite. Whenovervalued or undervalued conditions present themselves, arbitrageursinitiate what is called "program trading," which automatically "executes"the routines that I have just described. Program trades are typicallygigantic and often cause sharp price movements when initiated. For DayTraders who understand how this aspect of the market works, significant DayTrading opportunities exist.