I am trying to understand the dynamics behind how QQQ is priced. It seems to trade based on supply and demand, like any ordinary stock. The 100 individual stocks in the Nasdaq 100 also react to supply and demand. What keeps the two (the QQQ and the Nasdaq 100 as a group) from going in two different directions? How can the QQQ be joined at the hip with the prices of the 100 individual stocks and still react to supply and demand for the QQQ itself? Can you point me toward a source that can explain exactly how this all works? Thanks.