Valeant and Bill Ackman considering higher offer for Allergan

US pharmaceutical giant Valeant and activist investor Bill Ackman are thought to be planning to sweeten their bid for Allergan from $176 to $191 a share, valuing the Botox maker at $56.8bn.

If the deal completes, it would be the largest of the year so far, ahead of the $54bn price tag in Abbvie's attempted takeover of Shire.

According to the Financial Times and The Wall Street Journal, which both cited people familiar with the matter, Valeant and Ackman's Pershing Square vehicle are attempting to deter a potential approach from other parties, including generic drug manufacturer Actavis.

The $15-a-share boost in the cash-and-stock offer is equivalent to an increase of $4.5bn in the value of Allergan.

The rumoured bid of $191 a share represents a 2.5% premium to Allergan's share price of $186.20 on Tuesday, though is still short of the $200 price that Actavis is said to be considering, according to the FT.

The WSJ said that a new bid still depends on the price Pershing Share is willing to accept for its 9.7% stake in Allergan.