Full context here (which still doesn't explain the time period depicted in the linked chart): http://www.asymco.com/2011/02/02/making-it-up-in-volume-how-profit

Full context here (which still doesn't explain the time period depicted in the linked chart): http://www.asymco.com/2011/02/02/making-it-up-in-volume-how-profit-and-volumes-traded-off-in-the-fourth-quarter/ http://www.asymco.com/2011/02/02/making-it-up-in-volume-how-...