Microsoft is considering launching a hostile bid for search provider Yahoo as early next week if Yahoo does not begin talks soon, Chief Financial Officer Chris Liddell said today. Liddell repeated a threat by Chief Executive Steve Ballmer on Wednesday to withdraw Microsoft"s $31 a share cash and stock offer if Yahoo does not start negotiating. According to the CFO, Yahoo management has "unrealistic expectations" of its value. "We have been clear that speed is of the essence to make sense," he told investors on a conference call to discuss quarterly results.