"What I see operating here is the bigger fool theory," he said, the assumption that a year from now, there will be a bigger fool who will pay still more.

The answer is that they all wanted to make money off stocks and collectively drove up the prices in the so-called bigger fool theory: Buy at one price and sell to a bigger fool at a higher one.

And the higher the pop, the more you see the effect of the bigger fool theory, a model of investing that says you're golden so long as you can find someone to take shares off your hands at a higher price.