As investors' options have grown exponentially, the underlying market structure has become incredibly complex. And according to market structure expert Justin Schack, no one with a blank slate would recreate today's market structure. Schack, a partner at Rosenblatt Securities, says that despite all the complexity, it's not a fundamentally unfair system that should be "blown up". Instead, he believes investors have largely benefitted from the changes in market structure. He also argues that some advocates for structural change have ulterior motives. Filmed on April 9, 2019 in New York.