Three major German firms would be added to the country's mid-cap index MDAX after their stocks were floated in the Frankfurt Stock Exchange in the earlier part of the year. The three firms are Osram Licht AG, RTL Group and Evonik Industries. 

Deutsche Boerse, the stock exchange operator, announced late last Wednesday the move to replace three other German firms with the new listings announced. The three German firms that would move from MDAX to SDAX would be BayWa, Puma and SGL. The changes would take effect by September 23.

The performance of the three stocks is what justified the move to the MDAX. Osram, which spun off from Siemens last July, saw their shares gain 30% of value since July. RTL for its part had gained 38% since its debut in the Frankfurt index last April. On the other hand, Evonik had declined by 16% at around the same time. 

Aside from the removal of the three firms from the MDAX, other firms that would be moved are Praktiker, RTL, Highlight Communications, SMT Scharf and SKW Stahl-Metallurgie.