Institutions can place orders that are hidden from Level 2 book. Do these order remain "hidden" after they execute?
AAPL bid and ask are $157.90 and $157.92, and, there is a hidden order for 10M shares to sell at $157.91. Then it's matched by another hidden order to buy 10M shares at $157.91, that is these hidden orders didn't affect all regular orders on L2 book. Will regular/retail traders see the 10M shares in the volume bar, or we won't even know that huge amount of shares changed hands?