Billionaire activist investor Carl Icahn has given up his seat on the Yahoo board of directors, closing a tumultuous chapter in the Internet company's 15-year history.
Mr Icahn said in a letter to the board he did not believe Yahoo needed an activist investor as a director at this time, and that his attention was focussed on other matters. Friday's letter said his resignation was effective immediately.
Mr Icahn won his seat on the board in July 2008, in the wake of Yahoo's protracted - and ultimately fruitless - talks with Microsoft, which had offered $47.5 billion to buy Yahoo.
Yahoo chief executive Carol Bartz in January replaced Jerry Yang, who had rebuffed the software giant's offer. Instead, Yahoo and Microsoft announced a 10-year search partnership in July, in which Yahoo will use Microsoft's back-end search technology on its Web portal.
In his letter, Mr Icahn said he believed the Microsoft transaction would provide great long-term benefits to Yahoo and commended Ms Bartz on a great job.
A Yahoo spokeswoman said there were no immediate plans to find a replacement for Mr Icahn, and that the board would operate with 11 directors for the time being.
"Carl has been an important member of our board and has helped us through some significant transitions," Yahoo Chairman Roy Bostock said in a statement. "We are all grateful for his active role shaping the future of Yahoo."
Reuters