(Bloomberg) -- Lonza Group AG, the Swiss supplier for pharma and nutrition companies, said Chief Executive Officer Pierre-Alain Ruffieux will leave at the end of the month, the third surprise CEO departure in about five years.

The company didn’t give a reason for the change. Chairman Albert Baehny will take over as CEO on an interim basis while Lonza seeks a permanent successor to Ruffieux. The shares fell as much as 10% in Zurich trading, doubling their loss during the CEO’s almost three-year tenure.

The board decision likely reflects “a lack of confidence in execution,” Jefferies analysts Lucy Codrington and Peter Welford wrote in a note. 

Lonza expanded aggressively during the pandemic, adding staff in order to fulfill a supply agreement with Covid vaccine developer Moderna Inc. As demand for shots has waned, the Swiss company in July cut its earnings guidance.  

Recent months “have undoubtedly been challenging,” Baehny said in a statement. The company also supplies capsules for health supplements, where demand is declining. Baehny already became acting CEO in 2019 when Marc Funk stepped down after eight months in the role. Ruffieux then joined from drugmaker Roche Holding AG in November 2020. 

A spokesman declined to give the reasons for Ruffieux’s departure. He said Lonza would discuss its future at the capital markets day planned for Oct. 17. The sentiment on the stock could remain negative until more clarity emerges on the growth outlook, Citi analyst Vineet Agrawal wrote in a note. 

--With assistance from Lisa Pham.

(Updates with Lonza spokesman comment in sixth paragraph)

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