The semi-annual review of the Austrian indices by the Index Committee has resulted in a change in the composition of the ATX. Palfinger AG is returning to the Austrian benchmark index for the first time since 2010, replacing CPI Europe AG. There has also been a change in the ATX five, which comprises the five highest-weighted shares in the ATX: voestalpine AG has been added to the index, replacing VERBUND AG. The composition of the ATX is based on two key criteria: average daily share turnover (liquidity) and free float capitalization of the company.
In addition, the index review resulted in a change in the free float factor for STRABAG SE, which will be increased from 0.2 to 0.3. The free float factor reflects the weighting of the free float – i.e. the proportion of freely tradable shares – in the indices of the Vienna Stock Exchange. Holdings of less than 4% are considered free float. The higher the free float and thus the factor, the greater the weighting of the share in the index. All changes will take effect on 23 March. The next scheduled review of the composition of Austrian indices will take place in September 2026. The free float factors will be updated again in June 2026.
The ATX calculation is based on a purely quantitative methodology that is laid down in a set of rules. In accordance with "The Rules for the Austrian Indices of the Vienna Stock Exchange", the Vienna Stock Exchange may add or remove companies after the semi-annual review (March and September). The calculation parameters (number of shares, free float factors and representation factors) are reviewed on a quarterly basis (March, June, September and December). Once a month, the Vienna Stock Exchange publishes the "ATX watchlist", which ranks stocks according to liquidity and capitalised free float. Institutional investors, trading members, issuers of financial products, academics and the Vienna Stock Exchange contribute their expertise to the Index Committee, which decides on the rules governing the indices.
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