Dark pools are alternative trading systems (“ATS”) which allow off-exchange trading of securities for institutional investors. While any trades can be executed on a dark pool, they are typically used for block trades and are not accessible to the general public; trades on dark pools are executed anonymously and they do not display price quotes to the public. There are several advantages for dark pool participants executing large block trades on dark pools, rather than exchanges. First, the trades can be executed without the same market impact as if done on an exchange. Additionally, for all trades, there are lower transaction costs for dark pools.