SIX has decided to make changes to the index baskets on the basis of a recommendation from the Index Commission and in compliance with the SMI®, SLI®, SPI® and SXI® index rules.

The indices will be adjusted on 19 September 2025 after closing. The adjustment takes effect on 22 September 2025.

The latest additions to SMIM include Swissquote.

The SMIM comprises the 30 largest mid-cap stocks in the Swiss equity market that are not included in the blue-chip SMI index. As in the case of the SMI, the components are selected according to their free-float-adjusted market capitalization and based on their turnover.

The composition of the SMIM is reviewed once a year in September. Calculation takes place in real-time tick-by-tick, i.e. each new transaction involving a stock included in the SMIM causes the index to be recalculated.

The SMIM was standardized at 1,000 points on December 31, 1999.