Vienna Stock Exchange News

ATX Prime: New free float factors for Semperit and S Immo, ATX composition unchanged

(Vienna) The Vienna Stock Exchange reviewed the Austrian indices today and announces the change of free float factors. The composition of the national index ATX remains unchanged. The free float factor of Semperit AG Holding decreases from 0.5 to 0.4 following an accumulation by the investor de Krassny GmbH. For S IMMO AG, the free float factor decreases from 0.3 to 0.2 after disclosure of the stakes held by Immofinanz AG and CPI PROPERTY GROUP S.A., respectively. The free float factor expresses how many shares of a company circulate among the public and influences how strongly a share is weighted in the index. The changes will become effective on 20 March 2023. The next scheduled review of the composition of Austrian indices will follow on 5 September 2023, the free float factors will be reviewed again on 6 June 2023.

The calculation of Wiener Börse AG’s indices is based on a quantitative procedure. According to “The Rules for the Austrian Indices of the Vienna Stock Exchange”, the inclusion or exclusion of stocks from the ATX is reviewed twice a year (March and September). Decisions on new additions to the index are based on average daily trading volumes and the free float capitalization of companies. The Vienna Stock Exchange reviews the calculation parameters (number of shares, free float factors, representation factors) of the index on a quarterly basis. Once a month, the ATX watchlist is published. In the Index Committee, which met today and decides on the rules and regulations for the indices, representatives of institutional investors, trading members of the Vienna Stock Exchange, financial institutions that issue financial products on the indices, academic advisors and the Vienna Stock Exchange contribute their experience. A list of the Committee members is available.


For further information, please contact:



Julia Resch

Julia Resch

Head of Corporate Communications & Marketing, Spokesperson

+43 1 531 65-186




Laura Marchler

Laura Marchler

Corporate Communications

+43 1 531 65-153


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Semperit AG Holding