E-mini futures are futures contracts on the Chicago Mercantile Exchange that are electronically traded. Each e-mini future represents only a small portion of an entire futures contract, explains Investopedia. E-mini futures are available for the Standard & Poor's 500, the Nasdaq 100 and the S&P MidCap 400, among other indexes.
Investors appreciate e-mini futures because of their affordability and liquidity. In addition, round-the-clock trading is available for these futures. While e-mini contracts are also available on metals and commodities, typically the phrase "e-mini futures" refers to trading on stock indexes. The first e-mini future traded was the S&P 500, which the Chicago Mercantile Exchange introduced in September 1997, according to Investopedia.