Essentially we have not seen these levels aside from right before the historical crash of 1987 ("Black Monday"), the height of the NASDAQ bubble in 1999, and a few weeks in 2003-2004. Excluding 1987 one parallel to today and 1999 and 2003-2004 was a Fed gunning the system with easy money (Y2K money in 99, and at the time historic 1% rates that set the seeds of the housing fiasco in 2003-2004). Who says the Fed does not move markets?
We are now above any level in the post March 2009 period by a long shot, and even above the mood that hung over investors at the market peak in fall 2007. Our world shall be very interesting if the Fed ever takes its peddle off the metal.
Have a good Christmas.