Trading Securities - The Specialist / DMM Acting As A Principal
In the absence of public orders the specialist / DMM is required to provide liquidity and price improvement for the stocks in which they are assigned. DMMs are required to trade against the market in the absence of public orders. However, the DMM may now also trade for their own account at prices that would compete with public orders.
If the public market for XYZ is quoted as follows:
|10 X 10||20.45||20.55|
There is a 20.45 bid for 1000 shares and 1000 shares offered at 20.55
If a public sell order came in to sell the stock, the DMM could purchase the stock for their own account at 20.45 because they are on parity with the public. The DMM could also purchase the stock for their own account at 20.50 and would be improving the price that the seller would be receiving. This is known as price improvement. Alternatively, if a public buy order came in, the specialist / DMM could sell the stock from their own account at 20.55, because they are now allowed to compete with the public. They could also sell the stock to the customer at 20.50 because, once again, that would be providing price improvement for the order.The Specialist / DMM Acting As An Agent