Analysts have reacted with scepticism to rumours circulating that Novartis is poised to announce a major acquisition bid, with AstraZeneca and Germany’s Schering both mentioned in dispatches as possible targets.

Such a move would represent an abrupt volte-face for Novartis CEO Daniel Vasella, who said in January that the company was not looking to make any more big transactions, having just spent $14 billion on acquisitions in 2005 including $5.1 billion on Chiron, and instead wanted to grow organically and potentially via small-scale deals.

This is the second occasion this year Novartis has been linked to a bid for AstraZeneca, and earlier reports in February were met with similar scepticism. Indeed, cash-rich Novartis has been a perennial subject of M&A speculation, having also been linked to bids for Serono and SkyePharma in recent months.

The latest rumours suggested Novartis was considering a £40 ($70) a share offer for AZ, Europe’s third-largest drugmaker.

Analysts said that a merger between AZ and Novartis would lead to serious antitrust problems because of the overlap in their product portfolios. A merger between AZ and GlaxoSmithKline may be more likely, they said.

Shares in AZ rose more than 4% in London on the back of the speculation yesterday to close at £28.32.