Goldman Sachs, which worked on the aborted auction of Serono nearly six months ago, has retained its position as adviser to the Swiss biotech company on its Sfr16.6bn (€10.5bn) takeover by Merck, the German pharmaceuticals company.

A spokeswoman for Merck, which lost out to domestic rival Bayer in a €17bn battle to acquire Schering in June, said the company had advised itself.