NASD member firms such as GS have ability to enter quotes, execute orders and send information because they are registered market makers and enjoy Level 3 trading service of Nasdaq. Trading volume of Level 3 service is forever secret. This kind of secret belongs to deepst Dark Pool.
I love AI-Trading but I dont believe my Program can make money because I can only buy "real-time quote" of Level 1 currently. Real-time quotes of Level 1 show me quote but it doesn't show me the order sizes of big player.