"We regard the offer as economically insufficient," Cascade International Investment said in a statement on Wednesday.

Grammer has been at the centre of a power struggle between Bosnia's Hastor family and Ningbo Jifeng, which each hold shares of at least 20 percent in the company.

Cascade, a company controlled by the Hastor family, has accused Grammer's management of market manipulation to help Ningbo Jifeng build a stake.

By contrast, Grammer's management has welcomed Ningbo Jifeng, another supplier of vehicle interior components, as a potential white knight in its conflict with Hastor.

Chinese auto supplier Ningbo Jifeng Auto Parts on Tuesday said it is aiming to bid 61.25 euros per share, valuing the group at around 772 million euros (674.3 million pounds), including dividends.

(Reporting by Edward Taylor; Editing by Ludwig Burger)