Here's my analysis and estimate of what the buyout could be. The more time before the buyout, the higher it could be assuming that Ali market cap grows and Yahoo shows some growth.
Alibaba at $250 Billion market cap means Yahoo's remaining 18% stake is worth $45 Billion, before taxes.
The overall pretax totals for Yahoo could be as follows:
Net Cash = $10 Billion
Yahoo Japan = $9 Billion
Ali Stake (18%) = $45 billion
Yahoo Core(??) = $8 billion
That total = $72 Billion.
The only way Yahoo is acquired for $72 billion is if it is by Alibaba or Softbank, who would save billions in taxes.
However, if another company comes along and low balls Yahoo let's say for $50 Billion, Ali and Softbank would be silly if they didn't outbid the other buyer. That's why I feel $60+ will be the number. But that's just my opinion.
If you take 35% out of the $45 and $9 billion, you get a reduction of $18+ Billion. So the value of Yahoo would drop to $54 Billion.
But there would definitely be some premium to that, especially with the longer term prospects of Alibaba. That's why, again, I am predicting $60+