Chemical producer Lanxess is set to exit Germany’s DAX 30 index of blue chip stocks on Sept. 21 and move back to the M-DAX of medium-sized companies. The relegation reflects a slump in market capitalization for the world’s largest producer of synthetic rubber.

The company’s share price has been declining steadily over the past year, due to persistent overcapacity in the rubber market, coupled with weak demand and lower selling prices for its products.

Following its carve-out from Bayer in 2004, Lanxess made its stock market debut in Frankfurt’s M-DAX index of medium-sized companies on 31 January 2005, with Bayer shareholders receiving one share in the newly independent company for each ten Bayer shares held.

The chemical company now based in Cologne was admitted to the DAX 30 in September 2013, shortly before then-CEO Axel Heitmann, blaming price weakness and inventory reductions, announced that management had narrowed its guidance for full year 2013.

In January 2014, the supervisory board abruptly dismissed Heitmann, replacing him in April of last year with former CFO Matthias Zachert.

For full year 2014, Lanxess reported a net loss but for 2015 has upgraded its forecast twice, citing progress in its realignment scheme. Zachert is due to reveal the outcome of plans to partner or divest the ailing rubber business later this year.