Prices go up and they go down, but give stocks enough time and they deliver returns that trounce those of bonds, real estate, commodities or any other asset class.

This led to easy credit and multiple bubbles in the United states-in technology stocks, bonds, real estate.

To balance out the equation, Americans, in the aggregate, either have to sell assets (stocks, real estate) or borrow money from abroad (by issuing Treasury bonds) to pay for the goods they buy.