Carl Icahn has dismissed claims by Amylin Pharmaceuticals that the billionaire investor and shareholder is looking to engineer a quick sale of the company to Eli Lilly.

In a letter made public on Monday, Amylin director James Wilson said that Mr Icahn, who has a 9% in the firm, was pushing for a sale to Lilly, its partner on the diabetes drug Byetta (exenatide) but rejected the idea, saying that “a sale of the company today would dramatically undervalue” the company. He came to this conclusion after phone calls with Mr Icahn but the latter says this “completely mischaracterised what was said during the conversations that took place between us during the past weekend”.

To begin with, Mr Icahn says “I absolutely did not say that Amylin should be sold ‘promptly’." He had pointed out that Lilly paid “a huge premium over market” for ImCloneSystems last year, a firm which Mr Icahn had taken control of two years earlier and Lilly’s chief executive John Lechleiter has recently stated publicly that he was looking for more acquisitions.

However, he goes on to say that “it is a complete misstatement on your part to any way suggest that I wish to sell Amylin to Lilly at today's prices. Quite to the contrary!” Mr Icahn added that “no one has ever accused me of selling cheaply” and he would “certainly not recommend selling Amylin unless we were offered at least over $30 per share, at which time I might recommend selling it.”

Last week, Mr Icahn nominated five new directors in a proxy fight with the Amylin board, and another shareholder, Eastbourne Capital Management, has done the same. In the letter he notes that “for a number of years I have had conversations with CEOs and chairmen, often over a crucial weekend, in order to end or avoid a ‘debilitating’ proxy fight, as you have characterised what is going on at Amylin.

He adds that “often these conversations have become ‘heated’. However, never until today has either side found it necessary to slant and misstate these conversations and then release these misstatements”. Mr Icahn concludes that by asking “do you intend to keep your word and set up the three way meeting between the company, Eastbourne and Icahn as you promised you would” or was this “just another empty promise”?

It looks as though this difference of opinion has plenty of mileage left in it