Shire is reportedly making a move on Swiss biotech giant Actelion, according to UK newspaper The Sunday Times.

Citing sources close to the situation, the paper said Shire had already laid an offer of around £12.4 billion on the table, but that this had been rebuffed despite representing a 20% premium on Actelion’s recent stock value.

Both companies remain tight-lipped over the rumours, declining to comment on media speculation.

But the move would fall in line with Shire’s current taste for value-boosting M&A deals to help bolster its cash flow, which has already secured it acquisitions of Meritage Pharma for $70 million (in February) and NPS for £5.2 billion (January).