A large investor in German energy company RWE is opposing a swift exit from brown coal operations, in a blow to activist investor Enkraft Capital, which has been pushing for the move to improve the valuation.

The Association of Municipal RWE shareholders (VkA), which controls a 14.1% stake worth around 3.6 billion euros ($4 billion), said the divestment of the company’s brown coal division would negatively impact the local economy and jobs.

“The course cannot be altered overnight. Such a path needs to be supported by measures to cushion the impact,” Ingolf Graul, VkA’s co-managing director told Reuters. “A fast exit from coal has consequences for jobs, the regional economy and also on trade tax. Municipalities must always keep this in mind,” he added.

Enkraft has been pushing RWE to get rid of its coal operations, arguing the stock was “no longer investible” for certain ESG investors. Divesting coal could double the stock price, according to Enkraft.

RWE has previously said that selling the brown coal unit would not accelerate Germany’s targeted coal exit.

Last month, Enkraft sent another letter to RWE, saying it was “at least doubtful” whether the board was able to meet the new challenges that have emerged as part of the company’s shift toward renewables. RWE said in response it rejects Enkraft’s “assessment that the supervisory board primarily limits itself to formal aspects of its function.”