They have an assload of cash on hand and the singularity is coming at us like a freight train. I'd think they were drunk if they weren't snatching up everything relevant in sight.
I wonder if they managed to pay for DeepMind out of funds that are "stuck" offshore (i.e. earnings from outside the US that can't be repatriated without incurring a big tax bill).
Plus, as buffet teaches, its better to reinvest the dividends. Unless the shareholders think they can do better than the management, in which case they're free to divest.
