To put it simply, the price is chosen to allow the biggest number of transactions or, alternatively, the biggest turnover at any given moment. Example: Price

To put it simply, the price is chosen to allow the biggest number of transactions or, alternatively, the biggest turnover at any given moment. Example: Price Buy Sell 124 € 130 pcs 50 pcs 125 € 120 pcs 90 pcs 126 € 70 pcs 90 pcs 127 € 30 pcs 100 pcs In this case, the price would be 125 €. 90 transactions can happen at this price; there is no other price which allows more transactions to happen because of the supply and demand constraints.