Annual meeting of German pharmaceutical and chemical maker Bayer AG in Leverkusen
Werner Baumann, CEO of Bayer AG arrives at the BayKomm Communication Center, Germany, April 28, 2020. Reuters

A top-10 shareholder in Bayer on Tuesday called on the group's supervisory board to replace chief executive Werner Baumann quickly, adding to investor pressure to restore trust and revive the German drugmaker's sagging share price.

Despite recent improvements in the company's agriculture business and drug development prospects, Bayer shares have been weighed down by litigation related to a product it acquired through its 2018 takeover of Monsanto. Shareholders have also cited a lack of market trust in its top management.

"When it comes to CEO succession we say: the sooner the better," Markus Manns, a portfolio manager at Union Investment, one of Bayer's 10 biggest shareholders, told Reuters.

The demand comes within days of another major German portfolio manager saying that Supervisory Board Chairperson Norbert Winkeljohann must speed up the search for the successor to Baumann, who has led the company for nearly seven years.

Ingo Speich, head of sustainability and corporate governance at Deka, was quoted in Saturday's Frankfurter Allgemeine Sonntagszeitung newspaper as saying Baumann had lost market credibility and so could no longer initiate strategic changes.

The mutual funds firm is among Bayer's 20 largest shareholders.

"The Bayer stock is in a crisis of trust which the executive board is responsible for," Speich told Reuters on Tuesday.

"Bayer has to take investor demands more seriously going forward. The Bayer stock is currently reacting more strongly to news from investors than to operating results. That's a clear sign that something is wrong," Speich added.

Union Investment's Manns cautioned that the non-executive supervisory board may need time to find a qualified candidate.

"I'm sure the board is aware of the urgency of this personnel issue," said Manns.

Baumann, who engineered the troubled Monsanto deal, was given a new contract in 2020 that runs until 2024 and said at the time he would leave the company when that term expires.

A spokesperson said Bayer was always open to a constructive dialogue with shareholders and declined to comment further.

Bayer is also facing demands from activist investor Bluebell Capital Partners to break up the company, including selling off its consumer health unit and later separating its pharmaceuticals and agricultural businesses.

Another activist investment fund, hedge fund veteran Jeffrey Ubben's Inclusive Capital Partners, said this month it had also acquired a stake in Bayer, whose products include painkiller Aspirin, Yasmin contraceptives and stroke prevention pill Xarelto.

A stalwart of German industry with a nearly 160-year history, Bayer has lost over 40% of its market value since the Monsanto deal, which was followed by a string of lawsuits over allegations that Monsanto's Roundup weedkiller causes cancer.

($1 = 0.9308 euros)

Graphic: Bayer has lost almost half its value since buying Monsanto