The Microsoft offer was for $45B: http://news.microsoft.com/2008/02/01/microsoft-proposes-acquisition-of-yahoo-for-31-per-share http://news.microsoft.com/2008/0

The Microsoft offer was for $45B: http://news.microsoft.com/2008/02/01/microsoft-proposes-acquisition-of-yahoo-for-31-per-share http://news.microsoft.com/2008/02/01/microsoft-proposes-acqu... The market cap of Yahoo was still around half that when Mayer was appointed. But that was all from their stake in Alibaba, which has already been spun off. The rest of Yahoo had a negative value, I think. So it's gone from 0 (conservatively) to $5B.