Margin Debt

Source: http://www.nyxdata.com/nysedata/asp/factbook/viewer_edition.asp?mode=table&key=3153&category=8

What happens when Margin Debt reaches an all-time high and then declines?  It is either a leading indicator of a stock market crash and recession, or ... nothing.  This is prone to false signals.  But you can't discount the first possibility.

In March 2000, margin debt reached an all-time high of $278.5 billion.  The recession began in March 2001, 12 months later.

In July 2007, margin debt reached an all-time high of $381.4 billion.  The recession began in December 2007, 5 months later.

In April 2015, margin debt reached an all-time high of $507.2 billion.  The recession will begin in .. maybe October?, 6 months later.