Off-exchange trading today has become defined by its opacity. Indeed, the framing of this symposium on What Happens in the Dark: An Exploration of Dark Pools and High Frequency Trading and its goal of exam[ing] a portion of the modern market that remains largely outside of the public eye l is much in line with contemporary thinking in policymaking, academic, and industry circles alike. Yet, off-exchange trading through dark pools and the like is far more transparent than thought, and exchange trading the opposite. In fact, much trading through off-exchange platforms is even more transparent than that facilitated by exchanges.
Despite these realities, the supposed contrast between exchange and off-exchange trading along this dimension continues to be highlighted-often along with a claim that it poses core securities-law problems. All the while, a clear-cut distinction between these two general types of trading platforms has gone relatively unnoticed: exchanges must welcome all traders, yet off-exchange platforms can engage in targeting and excluding. This trader-access distinction, I argue, should matter for those who care about the chief ends of modern securities law-and a good amount of the current transparency-distinction focus should therefore be reallocated toward the access one
