isn't there another component to the NYSE auction where the DMM has some input into what the closing/opening price actually is?
The price is usually calculated algorithmically by the DMM firm and sent to the person at NYSE to approve. Pretty arcane. Also somewhat shady, as the DMM firm can be and is part of the auction themselves. DMM firms can analyze the order book to see what the imbalance is in the overlapping region, and place an order of their own to correct the imbalance and then set the opening price. I can see how one can profit from this in certain situations