Stock Market Adjustments: Fluctuations in the DAX Family Index observed in September

The Deutsche Börse subsidiary ISS Stoxx has announced significant changes to several indices, set to take effect on September 22, 2025. These changes will see some companies moving between the DAX, MDAX, and SDAX, the indices that represent the German stock market's leading, mid-cap, and small-cap stocks, respectively.

One of the most notable changes is the departure of the sports car manufacturer Porsche from the leading DAX index. Porsche, with the ticker symbol PAG911, has been a member of the DAX since December 2022. However, it will move up to the German leading index, replacing Scout24 SE, which is moving in the opposite direction, from the MDAX to the DAX.

Another company moving up from the MDAX to the DAX is GEA Group AG. The pharmaceutical and laboratory supplier Sartorius AG, on the other hand, will leave the DAX index and join the MDAX, the index for mid-cap stocks. Sartorius AG has been struggling with sales issues, and its stock has lost around a third of its value in the past 12 months.

Fielmann, a retailer specialising in eyewear and optics, is moving up from the SDAX to the MDAX. Meanwhile, 1&1, a telecommunications company, is replacing both SGL Carbon and Formycon in the SDAX. In September 2021, Sartorius was added to the DAX as part of an index reform when Deutsche Börse increased the number of stocks to 40.

Evotec, a biotechnology company, is leaving the MDAX. These changes mark the third major index adjustment this year for the DAX family.

It is important to note that index changes can impact stock prices, particularly for funds that physically replicate indices and need to adjust and rebalance their portfolios. These changes in the indices could potentially lead to shifts in the stock prices of the affected companies.

These changes are part of the ongoing evolution of the German stock market, reflecting the shifting fortunes of different sectors and companies. As always, investors are advised to closely monitor their portfolios and make informed decisions based on the latest market developments.