Hidden Order
A hidden order (also called a dark order or iceberg order) is an order placed on a stock exchange where all or most of the order quantity is not visible to other market participants. Only a small portion (the displayed quantity) is shown in the public order book, while the rest is hidden.
What Is a Hidden Order?
In most exchanges, the order book is visible to all participants, showing buy and sell orders with their quantities and prices. A hidden order shows either:
– Zero quantity (fully hidden): the order’s existence is known only when it executes
– Partial quantity (iceberg order): only the disclosed portion is visible; as each tranche executes, the next tranche appears
This prevents other traders from detecting large buying or selling interest that could move the market.
Hidden Orders vs Disclosed Quantity Orders
These terms are closely related:
– **Disclosed quantity orders**: show only a portion; as one tranche fills, the next is revealed at the original price
– **Fully hidden orders**: not visible in the order book at all; execute only when a matching order appears
Why Use Hidden Orders?
– **Institutional investors**: prevent price discovery of their large trades before execution
– **Reduce market impact**: announcing a large buy or sell often causes prices to move against the order
– **Competitive trading**: prevent front-running by high-frequency traders who detect large orders
Regulatory Perspective
SEBI allows disclosed quantity orders on NSE and BSE with a minimum display requirement (usually 10% of total order). Fully dark or hidden orders are less common on Indian exchanges; institutional dark pools operate through alternative mechanisms.
Practical Example
A mutual fund wants to accumulate 5 lakh shares of a small-cap stock over a week. Showing the full order would cause the price to spike as other traders anticipated the demand. Instead, the fund uses iceberg orders showing only 5,000 shares at a time. The large order is gradually filled without significantly alerting the market.
Key Takeaways
– Hidden orders conceal all or most of the order quantity from the public order book
– Iceberg orders show only a portion (disclosed quantity); the rest is hidden and revealed tranche by tranche
– Used by institutional investors to prevent market impact and front-running of large orders
– SEBI requires a minimum disclosed quantity of 10% for equity orders on Indian exchanges
– Dark liquidity and hidden orders are more prevalent in international markets; India requires partial disclosure
