Shares in Germany’s Merck KGaA dropped yesterday as news of chief executive Bernhard Scheuble’s sudden departure sank in. The surprise move clearly caught investors on the hop, and the firm’s stock was down almost 7% across Europe yesterday – the biggest drop in months.

Analysts have already started speculating that Dr Scheuble has had a disagreement with the Merck family, potentially over the company’s future strategy. The German firm has seen strong performances of late, with a 57% increase in third quarter net income to 182 million euros, and annual sales of almost 6 billion euros. Dr Scheuble headed the firm for five years, ensuring it became the third biggest generics drugmaker in the world. A spokesperson for Merck conceded to Bloomberg News that the move was for “personal reasons,” and was not linked to business performance.

Dr Scheuble will be replaced by board member Michael Roemer.