This is an off quoted, frequently misunderstood statement. If you assume zero discount of the Alibaba stake due to taxes or other uncertainty, then Yahoo has z

This is an off quoted, frequently misunderstood statement. If you assume zero discount of the Alibaba stake due to taxes or other uncertainty, then Yahoo has zero or negative value. However, there is >0% chance that the Alibaba stake will be taxed or that Yahoo leadership will sell and spend the money instead if returning it to the shareholders. The more accurate statement is that the uncertainty a "core" business brings outweighs the value of said business. Part of that uncertainty is the tax treatment issue of BABA shares, the other part is a vote of (or lack of) confidence in Yahoo leadership. Yahoo itself has plenty of value. Probably not 10B, but probably more than 1B.