"Even the most circumspect friend of the market would concede that the volume of brokers' loans - of loans collateraled by the securities purchased on margin - is a good index of the volume of speculation."
- John Kenneth Galbraith, The Great Crash, 1929
January margin debt figures were recently released (chart below via dshort.com), and almost immediately, prominent pundits jumped to allay the natural concerns regarding the sheer amount of leveraged speculation in the market at present. Their common refrain has been to suggest that it's not the amount that is important, but