FRANKFURT German pump maker Pfeiffer Vacuum's (PV.DE) management and supervisory boards told shareholders to reject a takeover offer from rival Busch as too low.
Family-owned Busch has offered 96.20 euros per share for Pfeiffer, valuing the group at around 949 million euros ($1 billion) and said last week it had secured more than 30 percent of shares in Pfeiffer already.
Pfeiffer said in a statement on Monday that the premium that Busch was offering was well below that paid in comparable transactions and was around a 7.5 percent discount to its share price on Feb. 10, the last trading day before Busch published its offer document.
Management and supervisory boards at German companies make formal recommendations on takeover bids.
Pfeiffer said it believed that Busch could actively interfere with its strategy, as it had already made several attempts to influence decisions that were up to Pfeiffer's boards.
"Adding to this concern is the fact that the Busch Group has been changing its stated intentions with regard to its stake in Pfeiffer Vacuum within a short period of time," it said.
The acceptance period for Busch's bid started on Feb. 13 and runs through to March 13.
Shares in Pfeiffer closed at 101.70 euros on Friday.
Pfeiffer makes pumps used by manufacturers including semiconductor firms and makers of analytical devices such as electron microscopes. Busch describes itself as one of the world's largest makers of vacuum pumps, blowers and compressors supplying all industry sectors.
(Reporting by Maria Sheahan; Editing by Alexander Smith)