As an ex-Yahoo!, it's sad to see the market value them so low. Yahoo has stakes in both Alibaba (16.3%) and Yahoo Japan (35%). Taking these out of the market cap, the market currently values Yahoo's core business at $833 million today. And if you look at the chart for the last 3 months, you can see that for much of the time, the core was valued at less than $0. In the first half of Nov, it was valued between negative $2—$6 billion! If I had been paying attention, I would have bought stock then; Seems like an obvious arbitrage opportunity.