There is a serious confusion here. What matters is not the amount of new debt this year, but the accumulation of debt. What matters is how much American businesses and individuals owe, not how much new debt they are taking on this year. Measured correctly, the stock of private debt is at historically record high levels. Let's look again at U.S. private debt.
History shows all stock market collapses occur with a heavily indebted private sector.
Indebtedness is a sign of confidence. The lender trusts the debtor will be able to pay the principal and interest on time. The debtor believes he will have the money to repay on time. When over-indebtedness accelerates it becomes a sign of overconfidence, and, in the latter stages, euphoria. Euphoria is rampant before the crash, as Prof. Charles Kindleberger has shown in his historical studies of financial crises.