The takeover bid, announced Tuesday, July 15, valued Continental at 11.2 billion euros ($18 billion), with Schaeffler offering 69.37 euros per share in cash.

The board of Continental, which is best known for tires but generates most of its turnover from braking systems and other vehicle safety features, said on Wednesday that the bid was opportunistic and lacked industrial logic.

Tough times for car industry

The Hanover-based company is nearly three times the size of the family-owned Schaeffler Group, which is based in the small Bavarian town of Herzogenaurach.

However, a slump in the car industry combined with an 11-billion-euro acquisition last year has helped drive down Continental's shares, leaving the group exposed to possible takeover attacks. At one point recently, Continental's shares had halved in value over the last 12 months.

Schaeffler said Tuesday it had secured the rights to about 36 percent of Continental's shares, and the bid caused Continental's shares to soar.

If Schaeffler's offer succeeds, the two companies will have a combined turnover of about $33 billion.