SDAX® starts directly below the MDAX® index and comprises the next 50 largest companies by market capitalisation and stock exchange turnover from classic sectors in the Prime Standard of the FWB® Frankfurt Stock Exchange.
The index composition is generally reviewed on a quarterly basis and adjusted with effect from March, June, September and December. Criteria for the weighting of the shares in SDAX are: stock exchange turnover and market capitalisation based on the free float.
Source: www.boerse-frankfurt.de