Electronic Trading: The Role of a Specialist

The NYSE facilitates trading through a human being who is known as the specialist. Each stock listed on the NYSE is allocated to a specialist and all the buying and selling of a stock occurs at the location of this person, known as "the trading post." Buyers and sellers represented by a floor trader will meet at the trading post to learn about the best current bid and ask price for a security. These bid and ask offers are called out loud and indicate the current prices to any interested party. A trade will be executed when the bid and ask orders meet. (For more insight, see Why The Bid-Ask Spread Is So Important.)

The specialist doesn't only match up buyers and sellers. Many specialists are forced to hold an inventory of shares themselves to minimize the imbalance of buy and sell orders. The specialist does this until an equilibrium price is reached, which is when demand and supply are very close. Buying an inventory of stocks is not a common occurrence. In fact, it is estimated that a specialist will be in on only one out of every 10-15 trades.

Another duty that a specialist attends to occurs if a customer's order is priced at a level higher than the lowest ask, or lower than the best bid price (known as a stop order). The specialist will then hold the order and execute it if and when the price of the stock reaches the level specified by the customer. (For related reading, check out Understanding Order Execution and The Basics Of Order Entry.)

A final responsibility of the specialist is to find a fair price for each of the stocks that he or she is responsible for at the beginning of every trading day. This fair price is based on the current supply and demand of the stock. The NYSE opens for trading at 9:30am, but if the specialist can't find a fair price, he or she may delay the opening of trading on a stock until that fair price is found.

It is the specialist's job to act in a way that benefits the public. Because specialists are responsible for keeping the market in equilibrium, they are required to execute all customer orders ahead of their own.