Dark Pools and Short Volume

A dark pool is a privately organized trading forum, which gives certain types of investors the ability to place trades without publicly revealing their intentions. The data offered for short volumes comes from three sources, the Financial Industry Regulatory Authority (FINRA), the Chicago Board Options Exchange (CBOE), and the Nasdaq PSX/BX quote. The short volume displayed is a daily volume figure, shown as a percentage of total trades on the ratio column.