the entire SPI capitalization. Thus, trading volume and capitalization are the determining factors in the quarterly rankings. The composition of the index is reviewed annually on the third Friday in September. Fixed number of 20 securities The SMI comprises a fixed number of 20 securities as of the ordinary review date in September 2007. Prior to this date, the index contained 25 listings. It is worth noting that the number of constituents of the index (20) is below the generally accepted minimum sample size of 30 required to reach statistical significance. Capped weightings In 2017, in order to address the issue that the top three constituents (Nestlé, Roche, Novartis) account for more than 60% of the index capitalization, SIX Swiss Exchange changed the rules of the SMI to introduce capped weighting. The weight of any constituent in the SMI index can no longer exceed 18%. Readjusting any weight exceeding 18% down to that value is done, in principle, on a quarterly basis. However, whenever a constituent reaches a weight exceeding 20% during a quarter (intra-quarter breach), then the weight is brought back to 18% without waiting for the next quarterly review. To make the transition smoother, there was an initial transition period during which these changes were progressively implemented, in steps of at most 3% per quarter. Additionally, a new index, the SPI 20, was created to continue indexing the 20 SMI constituents without any caps. SMI constituents Current constituents As of 16 September 2022, the following 20 stocks make up the SMI index. The rank is based on free-float capitalization as of 31 August 2022. The first ten weights are given as of 31 August 2022. The other weights are given as of 23 March 2020. The latest update following the ordinary review was implemented on 16 September 2022, when Sonova replaced SGS. SMI family SMI is also the name of a family of indices encompassing the SMI itself, but also the SMI MID with the next 30 large-caps (2) and mid-caps (28), and the SMI Expanded with all 50 shares. The indices are available in several variations. For example, the SMI, which is a price index, also exists as a performance index, the SMI Cum Dividend (SMIC), which takes into account dividend distributions. History Historical values The following table shows the annual development of the Swiss Market Index since 1988. Milestones The following table shows historic milestones of