CNBC' Trading Nation writes ( http://www.cnbc.com/2015/10/29/this...0-and-2007-crashes-and-its-falling-again.html ) Interesting premise, and it may be worth a deeper look. The CNBC piece didn't detail the source of the data for the embedded graphs, but the data may be from this page ( http://us.spindices.com/indices/strategy/sp-500-buyback-index ) on the S&P Dow Jones Indicies ( http://us.spindices.com/ ) web site. Has anyone done any past research on this thinking?