2.7.2. Block Trading
A broker-dealer may receive an order to buy or sell a large amount of a single stock at once. This is called a block trade or block order. For NMS stocks, any order for at least 10,000 shares or $200,000 total market value is considered to be a block order. Recall from Chapter 1 that NMS stocks include all exchange-traded stocks.
When a broker-dealer attempts to fulfill a block order on the NYSE, it may need to buy or sell the shares at a price other than what the stock’s DMM is quoting. This is called crossing the market, and