In finance, a basket is a weighted group (a linear combination) of several financial instruments. The purpose could be for example simultaneous buying or selling, for example during program trading. Certain specific specialized "baskets": A stock market index is a basket for all the securities in a particular exchange. A market basket is a basket for all the securities on a particular market. A combination of individual assets, used as an underlying of a basket option. See also Currency basket Securities (finance)