is better than the quoted bid price of $68 per share. Therefore, you may find that there are traders who were unwilling to sell their shares at the $68 bid price but are happy to sell shares to you at your higher bid price of $68.10. Until 1997, the minimum tick size on the New York Stock Exchange was $1⁄8. In 1997 the NYSE and all other exchanges began allowing price quotes in $1⁄16 increments. In 2001, the NYSE began to price stocks in decimals (i.e., in dollars and cents) rather than dollars and sixteenths. By April 2001, the other U.S. exchanges are scheduled to adopt decimal pricing as well. In principle, this could reduce the bid-asked spread to as little as one penny, but it is possible that even with decimal pricing, some exchanges could mandate a minimum tick size, for example, of 5 cents. Moreover, even with decimal pricing, the typical bid-asked spread on smaller, less actively traded firms (which already exceeds $1⁄8 and therefore is not constrained by tick size requirements) would not be expected to fall dramatically. Stop-loss orders are similar to limit orders in that the trade is not to be executed unless the stock hits a price limit. In this case, however, the stock is to be sold if its price falls be- low a stipulated level. As the name suggests, the order lets the stock be sold to stop further losses from accumulating. Symmetrically, stop-buy orders specify that the stock should be bought when its price rises above a given limit. These trades often accompany short sales, and they are used to limit potential losses from the short position. Short sales are discussed in greater detail in Section 3.7. Figure 3.4 organizes these four types of trades in a simple matrix. Orders also can be limited by a time period. Day orders, for example, expire at the close of the trading day. If it is not executed on that day, the order is canceled. Open or good-till- canceled orders, in contrast, remain in force for up to six months unless canceled by the customer. At the other extreme, fill or kill orders expire if the broker cannot fill them immediately.     Specialists and the Execution of Trades   A specialist "makes a market" in the shares of one or more firms. This task may require the specialist to act as either a broker or dealer. The specialists role as a broker is simply to ex- ecute the orders of other brokers. Specialists may also buy or sell shares of stock for their own portfolios. When no other broker can be found to take the other side of a trade, spe- cialists will do so even if it means they must buy for or sell from their own accounts. The NYSE commissions these