Icahn launches fresh attack on Yahoo board

Icahn called on the Yahoo board to scrap an employee retention plan that he claimed drove up the potential costs of a Microsoft takeover attempt to a prohibitive level. In a letter, he labelled the action a "poison-pill" - a corporate term which describes a company policy that deters would-be suitors from buying a company.

Meanwhile, Yahoo chairman Roy Bostock said Icahn's letter "seriously misrepresents and manipulates the facts".

The employee retention plan could trigger payments of up to $2.4bn (£1.2bn) if Microsoft pulled off a successful takeover by ensuring that employees are handed severance payments in the event of a company takeover.

Icahn said that scrapping that plan would encourage Microsoft to come back to the negotiating table.

In his letter he said: "One doesn't have to be a rocket scientist to realise there is a simple method" for luring another offer from Microsoft,. "Simply rescind the ... 'severance plan,' which would free up approximately $2.4bn and possibly even more, which could be added to the bid."

In response, Bostock said that Icahn's assumption that Microsoft will come back to the negotiating table for a full acquisition of Yahoo is "puzzling".

"During this period, their message to us and to the markets has been and remains that they are not interested in pursuing a full acquisition of Yahoo," he said.

"You make reference to our employee retention plan but you significantly mischaracterise its purpose and its effect. In fact, you refer to it as a "poison pill" which could not be further from the truth. To set the record straight, the employee retention program is designed to protect the company's assets and value during a time of uncertainty."