What is the SMI?

SMI® – THE Blue-Chip Index of the Swiss stock market

The Swiss Market Index or SMI® is the most relevant stock index in Switzerland and includes the 20 largest stocks (blue chips) from the Swiss Performance Index (SPI). The capitalization of the SMI stands for nearly 80% of the entire Swiss equity market.

The weight of each index constituent is also capped to a maximum 20% of the total Index. This makes the SMI fully compliant with the ESMA and therefore it can be used as a reference index for the Swiss equity market in the European Union. 

Since the SMI represents the majority of the Swiss equity market, it is used as an underlying for derivatives and other financial instruments based on the Swiss market, like for instance futures, options, exchange traded funds (ETFs), or structured products.

The SMI is a price index. However, under the designation code SMIC (SMI dividend-adjusted) it is also a performance index.

On June 30th 1988, the SMI was standardized at 1'500 points. The Index owner, the Swiss Stock Exchange (SIX), reviews the composition once a year. During trading hours, the index is calculated in real time, which means that each new trade in the exchange involving a stock included in the SMI triggers a recalculation of the index.

The constituents of the SMI as of September 18th 2020 

smi constituents

Strong Performance of Swiss Stocks

A rebasing analysis (Base 100, Start: 1988) between the SMI and the MSCI World (Price Index) shows that the Swiss stock market has significantly outperformed the Global Stock Market over the last 50 years. 


screenshot graph

Swiss Market Index – SMI


The SMI measures the development of the Swiss Blue Chip equity market. The 20 largest and most liquid equity instruments traded on SIX are selected as components. The index represents more than 75% of the freefloat market capitalization of the entire Swiss market. Compared to the SPI 20 the SMI is calculated with a cap factor to limit the maximum weight of its components and is therefore sufficiently diversified in terms of the UCITS (Undertakings for Collective Investments in Transferable Instruments) guidelines. The SMI is a fixed component index.

Calculation Method

The SMI is calculated as a freefloat market capitalization weighted index using the Laspeyres method. The Laspeyres method and the weighting method are described in detail in section 4.1. For the SMI the rules for ‘Liquid opening’ are applied as described in section

SIX calculates a Final Settlement Value for the SMI.

In addition to the price and the gross return index, the following indices are calculated:

Additional SMI Indices

SMI Ask Index > Measures the development of the SMI components using the lowest ask quotes.

SMI Bid Index > Measures the development of the SMI components using the highest bid quotes.

SMI Current Spread > Outlines the spread between the SMI Ask Index and the SMI Bid Index.

SMI Average Spread > Outlines the arithmetic mean of the SMI Current Spread quotes at the end of each trading day

SMI Monthly Average Spread > Outlines the arithmetic mean of the SMI Average Spread quotes at the end of each month

Index Composition

Ordinary Index Review Frequency and Cut-Off Date

During the annual ordinary index review on the 3rd Friday in September, the index composition is based on the Selection list from June adjusted. For the key dates of March 31st, September 30th and December 31st, a provisional selection list created. It serves as the basis for adapting extraordinary corporate actions.

Component Selection Rules

The index universe of the SMI is the SPI. The following table provides an overview of how the SMI is based on the index

Selection list from which the SPI is selected:

  • Index : SMI
  • Anzahl Indexkomponenten : 20
  • Direktauswahl : Rang 1-18
  • Puffer : Rang 19-22

The 20 index components of the SMI are selected from the index selection list. To increase fluctuations in the index a buffer for ranks 19 to 22 is used. I.e. the first 18 components go directly into the Index added. From the candidates in ranks 19 to 22, those are given priority which are currently already in the index. Then new components are taken from the buffer until the Index has 20 components.

Instruments that are primarily listed on more than one exchange and less than 50% of their total turnover at SIX generate, must also meet a liquidity criterion in order to be selected for the SMI. For this purpose, all index components of the SPI will be submitted to the regular index review in September according to their Cumulative order book turnover of the last 12 months in relation to the total turnover of the index universe ranked in descending order. For this list, only turnover from the exchanges is taken into account on which the instrument is primarily listed. Such an instrument with several primary listings may not be more than 18 on this list to be able to be selected for the index. If a current index member is ranked 23 or lower on this list, it will be removed from the index.

Component Weighting

The SMI is weighted by the freefloat market capitalization of its components. The number of shares and the freefloat factor are reviewed on a quarterly basis as described further below. In the same context each component of the SMI with a freefloat market capitalization larger than 18% of the total market capitalization of the index is capped to the weight of 18%. Additionally, the components of the index are capped to 18% between two ordinary index reviews as soon as two components exceed a weight of 20% each. If such an intra quarter breach is observed after the close of markets, the new cap factors are calculated so that any component has a maximum weight of 18%. This cap factor is set to be effective after the close of the following trading day. If an issuer has issued more than one equity instrument (e.g. registered shares, bearer shares, participation certificates, bonus certificates) it is possible that one issuer is represented in the index with more than one instrument. In this case, the freefloat market capitalization of those instruments is cumulated for the calculation of the cap factors. If the cumulated index weight exceeds the 18% threshold, the weight is capped accordingly. The cumulative, capped index weighting is distributed to the different instruments based on their proportion of the free float market capitalization.

Maintenance of Components

1. Review of Number of Shares and Freefloat

Overview - The reviewed number of shares and freefloat factors are communicated to the market with the Review List. It presents the number of shares and the freefloat factor for each index component. It serves as the basis to calculate the freefloat market capitalization. The communication and implementation of the reviewed shares and freefloat factors follow the schedules shown below: 1st Quarter, 2nd Quarter, 3rd Quarter and 4th Quarter Communication of provisional figures on Monday, one month before effective date. The data cut-off takes place on Friday before communication of the results. The communication of definitive figures is on the Monday preceding the implementation. The implementation take place on Friday 3rd of March, Friday 3rd of June, Friday 3rd of September and Friday 3rd of December. The effective Monday after implementation SIX produces a provisional and a definite Review List. The provisional Review List is published one month before implementation and has an informative character. The definitive figures are published 5 trading days before implementation to ensure that they have the most recent data. SIX may update the figures up until implementation to react on not foreseen market developments, to correct mistakes or to adjust corporate actions.

Then comes the determination of the Freefloat Factor. The freefloat factor is a relative fraction multiplied with the number of shares in order to ensure that only shares that are available for trading are considered in the index calculation. The freefloat factor is only calculated for shares with voting rights. Large stakes that reach or exceed the threshold of 5% and are held in firm hands are subtracted from the total market capitalization. The following stakes are deemed to be held in firm hands:

  • Shareholding that have been acquired by one person or a group of persons who are subject to a shareholder or lockup agreement.
  • Shareholding that have been acquired by one person or a group of persons who according to publicly known facts, have a long-term interest in a company.


Independent from the above, the stakes held by institutions of the following kind are deemed free-floating:

  • Custodian nominees
  • Trustee companies
  • Investment funds
  • Pension funds
  • Investment companies


SIX classifies at its own discretion persons and groups of persons who cannot be clearly assigned because of their area of activity or the absence of important information. In order to calculate the size of a stake SIX uses the reports submitted under the art. 120 of FinfraG. In addition SIX may use data gained from issuer surveys that it conducts itself. Where an issuer has different categories of shares listed, these are considered separately for the freefloat calculation. Fund instruments are set to be freely tradable and therefore the freefloat factor is defined to be 100%.

2. Priority of prices in the reference value calculation

All instrument prices for calculating the index values ​​are unfiltered and are used by the trading platforms received by SIX during official trading hours. The last price paid is used for the index calculation. In order to take into account the different liquidities of the index components and to determine the representative opening value of the index (“open"), there are two opening procedures. For determining the final value of the indices ("close") a standardized closing procedure for all indices of this regulations is used.

Opening procedures

A. Standard opening

If no price was paid on the day of calculation, the bid rate applies. In the absence of the bid price, the price is taken from what was used to calculate the last index tick of the previous day. Only courses that are generated via the SIX electronic order book are taken into account. In order to take possible price fluctuations into account once the trading is opened, the Index calculation begins 3 minutes after the trading start.

B. Liquid opening

If no price was paid on the day of calculation, the price is taken from what was used to calculate the last index tick of the previous day. Only prices are considered which have been established through the electronic SIX order book. In order to take possible price fluctuations into account once the trading is opened, the Index calculation begins 2 minutes after the trading start.

Closing procedure

To calculate the closing price of the index, the definitive daily closing prices of the index components are taken from their closing auction. If there is no daily closing price, the price is used, from what was taken to calculate the last index tick

Final Settlement Value (FSV)

A Final Settlement Value (FSV) is calculated for indices on which derivatives are traded. The calculation of the FSV is based on the first price paid for all index components between 9:00:00 CET and 9:02:15 CET. If no price is available for an index component in this period, the last available price of the previous day will be used instead.

Index Components in a Non-Index Currency

If an index component is traded in a currency other than the index, it will be converted to the currency of the index for its calculation. The conversion takes place in real time (tick-by-tick) with

the last available mean rate of the exchange rate. For the index final value calculation (closing) the last available middle rate of the exchange rate is used.

Sources :


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