Indices trading is the means by which traders attempt to make a profit from the price movements of indices.
There are many indices available for trading, measuring the performance of the stock market of various different markets: including countries or sectors, or types of commodity. Indices traders can either focus on a single index, or trade various indices as part of a wider strategy.
It is not actually possible to buy or sell an index like you would a stock or commodity, as they are indicators of the price movements of several assets and have no actual physical basis to trade. Instead, indices traders use derivatives like index futures to speculate on the movements of various indices.