Quote from blakpacman:
It's kind of like Star Trek where the US monetary policy is boldly going where no man has gone before. We never had a world reserve currency country in full throttle quantitative easing. If the ES cracks, you already know what Janet Yellen will do. This is where being too tied to history, i.e. historical margin debt to GDP implying a high, may be a mistake. The entire full faith and credit of the US monetary system is being used to prop up risk assets with QE. Since our monetary system and Dollar still has a lot of credibility, one can say stocks can be propped up for a long time ... for many years if FOMC wanted until they get what they want to achieve ... i.e. the self-sustaining economy that has stubbornly failed to materialize thus far.
Hence, I would argue that future margin debt to GDP will make new all-time highs far above levels of previous stock market tops. The level of speculation forthcoming will shatter all previous known records. Let's welcome the forthcoming Tulipmania Squared.