A dealer is asked for a price upon which she will transact to trade 100,000 shares of XYZ, makers of zipper examiners for the masses. The dealer will give a price at which it will buy, and a slightly higher price at which it will sell. This is the "firm price" so if the other party says "I buy," then the dealer has to sell at the quoted price. Note that firm prices are only for 1 round lot of 100 shares. In this instance, a trade this large would involve some negotiation on the price.
