The semi-annual review of the Austrian indices by the Index Committee results in a change in the ATX composition.
STRABAG SE $STR (-0,53%) and PORR AG $POS (-0,86%) will be newly included in the leading Austrian index, replacing Telekom Austria AG $TKA (+0%) and Mayr-Melnhof Karton AG $MMK (+1,25%) .
The composition of the ATX is based on two key criteria: the average daily turnover of a share on the stock exchange (liquidity) and the freely tradable share of the company on the market (free float capitalization).
https://www.wienerborse.at/news/wiener-boerse-news/strabag-porr-atx-092025/