Yahoo! Inc., a month after hiring Scott Thompson as chief executive officer, added two directors and announced the departure of Chairman Roy Bostock and three others in a board shakeup aimed at spurring a turnaround.

Alfred Amoroso, a former International Business Machines Corp. executive who ran Rovi Corp. until last year, and Maynard Webb, EBay Inc.'s ex-chief operating officer, will join the board, Yahoo said today in a statement. Bostock, Gary Wilson, Arthur Kern and Vyomesh Joshi, meanwhile, won't stand for re-election as directors.

Yahoo, the biggest U.S. Web portal, has faced mounting pressure from shareholders to revamp management following years of declining sales and market-share losses to Google Inc. and Facebook Inc. The company, in the midst of a strategic review, said today it has weighed proposals for equity investments yet hasn't received an attractive offer. It continues to discuss a possible sale of its holdings in Asian assets, including Alibaba Group Holding Ltd.