The reference to iceberg stems from the idea that the “tip of the iceberg” is the only visible part of a large mass of ice emerging from a body of water. Accordingly, the term “Iceberg Order” is defined as the practice of breaking an order to buy or sell a large quantity of contracts into multiple smaller orders through the use of automated software. As the futures markets moved from open outcry execution to electronic, this order type has become increasingly more popular. This is because those traders, whether retail or commercial, trading large quantities typically prefer to mask the true volume from view of others. In other words, iceberg orders enable the “public” to see only a small portion of the actual order at a time.
Most futures trading platforms offer the ability to view DOM (Depth of Market) data in which it is possible to observe the working buy limit and sell limit orders of other traders. These working orders on display are often referred to as the “book”. Some traders monitor the trading book for large quantity orders. In theory, large buy orders indicate the market might be inclined to move higher, or at least it suggests that a large player, or players, believes it will. These inferences, whether right or wrong, can influence prices and possibly prevent the entity placing the large quantity to be filled at their desired price. As a result, funds and institutions placing sizable orders have incentive to mask the true quantity of their order. Simply put, those using iceberg orders do so under the belief that it will reduce the impact the order has on price movement as it is absorbed into the market.
When an iceberg order is placed, the trader determines the disclosed volume which will be placed as a regular limit order, and the hidden volume which is only placed once the first tranche is filled. For most retail traders, iceberg orders are not necessary but the ability to execute them is available on most futures trading platforms, so it is a good idea to understand what they are. However, it is typically not a good idea for average retail traders to use this order type. After all, those trading small quantities will have little or no impact on prices so there is no need to disguise the quantity. Furthermore, because the hidden quantity is only placed after the disclosed quantity, it will fall to the bottom of the priority list in the exchanges trade matching system. In other words, traders unnecessarily using iceberg orders are reducing their odds of getting filled at their limit price.
GTC (Good 'Til Canceled)
As the name implies, good ‘til canceled orders, often called open orders, are always considered active until filled, canceled, or replaced by another order. Beginning futures traders have been known to place GTC orders and forget about them only to find that disaster has struck while they weren't watching. If you are gong to use GTC orders make sure that you properly monitor them. Most platforms and commodity brokers assume futures orders are “day orders”, meaning they are canceled at the end of the trading session if they aren’t executed. Consequently, when entering futures orders intended to be active until otherwise canceled, it is necessary to convey it as such.