The Swiss Market Index (SMI) is Switzerland's blue-chip stock market index and is made up of 20 of the largest and most liquid large- and mid-cap stocks of the Swiss Performance Index (SPI), a collection of all securities traded on the Zurich-based SIX Swiss Exchange from companies based in Switzerland.

Unlike the SPIexternal link, the SMIexternal link is not corrected for dividends. Which shares go into the SMI are examined annually. The stocks traded in the SMI represent 90% of the entire market value and trading volume of all stocks listed on the SIX Swiss Exchangeexternal link, one of Switzerland’s two stock exchanges (the other being the Berne eXchange).

The SMI is considered to be a weather balloon for the Swiss market as a whole and is often used in formulating other financial instruments.