An iceberg order is a purchase or sale of a large number of financial securities. Iceberg orders are split up into numerous smaller orders rather than being recorded as a single large order. Because each little order reflects only "the tip of the iceberg". The term "iceberg" is used to characterize this approach of buying and selling securities. Iceberg orders are commonly used by large, institutional investors as opposed to retail investors that purchase and sell assets in lower volumes. 

When trading stocks or other financial instruments, institutional investors use iceberg orders as a method to achieve the best execution. A major institutional investor wants to avoid putting a massive sale order that might generate panic. A series of smaller limit sell orders may be more appealing and help to mask the existing selling pressure. 

An institutional investor, on the other hand, who wants to acquire shares at the lowest possible price should avoid putting a large buy order. As other market participants may take notice of this volume spike. 

How does an iceberg order work?

Iceberg orders operate by dividing a single large order into installments and putting them on the market in that sequence. Due to the fact that after one phase has been executed, the following phase is promptly reloaded onto the order books, iceberg orders are also referred to as “reloaders”. 

Iceberg orders receive their name from real icebergs because you can only see what's on the surface of the ocean and not what's underneath. This is similar to how this type of order hides the actual volume that is intended to be traded. 

How to detect iceberg orders? 

Iceberg orders can be identified by searching for a sequence of limit orders from a single trader that seems to repeat often. An institutional investor, for example, may divide a one-million-share purchase order into ten separate 100,000-share purchases. 

Traders must keep a careful eye on the pattern to see it and realize that these orders are being completed in real-time. Traders seeking to profit from these dynamics can purchase shares slightly above these levels. Knowing that the iceberg order will provide strong support. This allows them to do scalping trades. 

Hide and seek technique   

Most major exchanges have a system in operation for filing iceberg orders and monitoring their execution. A "max floor" option specifies the greatest slice of the iceberg order that may be shown at any given moment. 

A company can select how soon it replenishes an order from the reserve (even before the prior order is completed) and can randomize order sizes to hide the bigger iceberg order. 

A company can also place a "synthetic" iceberg order, in which a trader or brokerage firm splits the primary order into smaller orders and sends them to the exchange. When businesses submit to exchanges like CME Group, which explicitly marks exchange-generated iceberg orders, this approach is sometimes employed. 

Example of an iceberg order 

Let's suppose a major pension investment fund decides to make a $5 million investment in stock XYZ.  The announcement of the fund's involvement might result in a huge increase in the price of XYZ in a short period of time. To prevent this, the fund creates iceberg orders when it wants to trade high volumes. As it divides its initial order into ten smaller $500,000 units. This allows the pension fund to conceal the true volume of the order. Thus, it does not abruptly influence the price of the stock.

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