CNBC publishes the "fair value" of the difference between S&P 500 futures and cash each day, using interest rates and expected dividends until expiration. Is there "edge" in trading this during the day, buying futures when they are below fair value and selling when they are above? Of course one needs to wait until all the stocks have opened and the SPX cash level is meaningful. Is there any source of historical data on the S&P 500 futures fair value? It is possible to buy historical intraday data on the futures and on cash, but would need fair value data as well to test a strategy based on the futures premium or discount. Of course, institutions will do the "arb" of buying futures and selling stocks (or vice versa) when futures are undervalued, but individual traders cannot do this. I wonder if there is value in doing only the futures side of the trade.