The investor Carl Icahn has decided to resign from Yahoo’s Administration Board. According to the resignation letter sent by Icahn on Friday, this step is seen as a necessity as Yahoo doesn’t need an “activist” investor. Moreover Icahn mentioned he wants to focus his energy and time on other matters.

The billionaire Carl Icahn, who is amongst the first 50 wealthy people in the world, was last year in a public dispute both with the Board members and with the CEO and co-founder of Yahoo Jerry Yang because of their refuse regarding Microsoft’s taking over of the company. Following negotiations, Icahn managed to increase the number of the Board’s members from 9 to 11, for him and 2 of his councilors along with other 8 of the initial members.

Carl Icahn is well known for his hostile takeovers. A little before of the Yahoo conflict, Icahn sued Motorola (in which he is the second shareholder) in an attempt to impose 4 members in the Board and to determine the company to sell the mobile business.

According to the official letter, the resignation has immediate effect.