German stock operator Deutsche Boerse, which compiles the index, made the announcement late Monday. The change takes effect on September 19.
Deutsche Boerse periodically reassesses the composition of the index using trading data to measure market value and trading volume as a basis for deciding which companies to include.
Last year, the index went from 30 to 40 companies in the biggest overhaul in its history.
Siemens Energy, which left the DAX earlier this year, has been in the limelight recently as it and Gazprom expressed differences over repair work on the Nord Stream 1 gas pipeline.
Among changes to the MDAX mid-cap index, HelloFresh will make its debut, while utility group Uniper, which recently benefited from a government bailout, will be downgraded to the SDAX small-cap index.