The underlying index varies in different countries.

The fund's performance tracks the underlying index's performance.

A leveraged or super floater gives the investor increased exposure to an underlying index: the leverage factor is always greater than one.

A one-point move in the underlying index changes the value of that E-mini by $50 and the standard one by $250.

The price of the futures contract and the underlying index is guaranteed to be the same at only one time, when the contract expires.

And the decay in value increases with volatility of the underlying index.

A live news feed affects the underlying index and consequently, the futures prices.

Their absence was explained in part because stock index futures contracts did not trade at a large enough discount to the stocks of the underlying index.

For reasons related to interest rates and lower margin requirements to trade futures, a futures contract normally sells at a premium to the underlying index.

Meanwhile, the underlying index of the 500 stocks that make up the Standard & Poor's cash index closed at 343.70, down 1.13.