their stake in alibaba is currently worth about 38 billion, plus they already sold 9 billion this morning in the IPO. they also own 8 billion worth of stock in yahoo japan a seperate publicly traded entity, and they already had 3-4 billion in cash. Plus the core yahoo is profitable to the tune of 800 million-1 billion a year. despite all this the market cap is only 41 billion, there are some tax concerns when they sell their shares in alibaba and yahoo japan but its way under valued right now in my opinion