Swiss biotechnology company Serono went on the slide this morning after the firm announced an increase in share capital that has been interpreted in some quarters as a sign that it may be planning an acquisition.

The company said it will ask shareholder approval to sell up to 7.6 million shares over the next two years.

Serono put itself on the block last year but has failed to find a buyer, despite reports of interest from Novartis and GlaxoSmithKline, and the suggestion is that suitors have baulked at the $15 billion price tag set by the company.

Serono said the sale of the shares would give it financial leverage to pursue a number of options, including ‘a sale of, merger of or one or more acquisitions’.

The Swiss company posted 2005 sales of £2.6 billion, but suffered a net loss of $106 million for the year as it was forced to spend $704 million to settle criminal and civil claims that it offered kickbacks to doctors in return for prescribing its AIDS wasting drug Serostim (somatropin).

Serono’s shares were down a little under 5% to 918 Swiss francs in mid-morning trading today.