most models are based on a favorable tax outcome so unfortunately, all estimates will be majorly impacted by this development. i think most on the street will be shocked by this situation as most thought that Mayer's ties to Obama would help the company seamlessly bypass a major tax event. You're looking at cutting the value of the holding by 40% - it's a major haircut and one that will probably run the stock back down to the mid 20s, if BABA continues to suck wind. If Baba goes up, I'm sure YHOO will recover.
The challenge is that Mayer, for all the good that she's done and she's found a way to reignite the company, seems a bit too high on her high horse and that's her reputation . . . she's a tech geek with a pretty face and designer clothes and that, that my friends is a dangerous combination.